grained, true or not, will not go away. and tom and his children make a life as best they can. that's all for this edition of "dateline." i'm craig melvin. thank you for watching. >> i'm craig melvin. >> and i'm natalie morales. >> and this is "dateline." sheer exhilaration, pure joy. there's nothing like the freedom of summer camp, and there's no other camp like this. >> feels like i'm a normal person. >> here, night is day, day is night. because for these kids, the sun is the enemy. >> you can see when people are pointing. >> yeah. >> that must be kind of hard. >> called names. >> i said how dare you?

>> they live with rare conditions. >> it's so isolating. imagine if you have a child and they can never go outside. >> i don't think people understand the severity of it. i could potentially die. >> in this hour, an extraordinary look inside their world. >> she's more adventurous at night. >> shielded from the sun. >> he jumps from shadow to shadow, always on the lookout for the next safe place. >> welcome to "dateline." they live by night. they have no choice, because for the remarkable kids you will meet over the next hour, even a few minutes in the sun can cause serious harm, but as you'll see, they do have light in their lives.

it just comes from within. here is kate snow. >> most people would describe this day as beautiful. clear, blue skies. warm sunlight. you could gaze out into these waters for hours. that is, until your eyes catch a glimpse of this young girl, enjoying the day the only way she can. >> i like going outside to get fresh air instead of being stuffy inside. >> covered from head to toe, wearing a shiny face shield that seemed to reflect an entirely different world. >> it's kind of hard to let people in when they stare. >> her name is mckenzie. she lives here on an island off the coast of vancouver, canada. because of a unique medical condition, she has often worn this face shield. we first met her in 2014 when she was 13, very shy, a little guarded. >> some of them are looking. i don't know if it's because of

the camera or what you're wearing. do you notice people looking at you? >> i do, but i try not to focus on that. i kind of look at the ground so i don't really focus on people. >> you can see when people are pointing? >> yeah. >> that must be kind of hard. her outfit certainly wasn't what her mom, shannon, had in mind on the day she found out one of her twins was a girl. >> what did you dream you would do together? >> the dresses. kind of a lifetime of dress-up and makeup and everything else and shoes, hair, all that. >> but her vision of mckenzie's future would fall apart quickly and dramatically. it all started when mckenzie was almost a year old. shannon and her husband, shawn, noticed a rash on her face. >> it started to spread down her face and then spread down into her lip and her chin. >> mckenzie's pediatrician didn't know what it was. shannon took her to two different dermatologists. they, too, were baffled. >> stuff that we're using in the

house. household chemicals or something like that. i remember feeling helpless for that seven months. >> mckenzie also cried more, slept less than her twin brother. but as these difficult months went on, shannon noticed a pattern. >> it actually gets worse when we take her outside. >> she told mckenzie's doctor who then ran a special blood test and finally the doctor discovered the cause of mckenzie's bewildering illness. the sun. >> i was terrified. you don't expect a doctor to tell you that your daughter is allergic to the sunlight. >> technically, it's not an allergy. though people shorthand it that way. mckenzie was diagnosed with erythropoietic protoporphyria, known as epp. it's a rare genetic disorder that's extremely complicated. though the doctor's instructions to shannon on the day mckenzie was diagnosed were very clear. >> it was a matter of taking off

my jacket to cover her. >> you weren't even prepared to cover her up in the car. >> no, not at all. my mom and dad in i in the elevator scrambling to cover her up, get her in the car and get her home. >> that was in 2002. after that, mckenzie would have to spend time in her room with her thick black curtains drawn. >> the worst experience is the guy calling me a vampire. it's just like one of those things, you can't really do much about it. >> if the sunlight hits her skin for too long, she suffers extreme pain, itching and swelling. >> it will be like a burning kind of feeling like you got stung by a whole bunch of bees. >> some patients said it was like dipping their hand in boiling water or being stabbed by a hundred knives. >> one of the few doctors in the u.s. who specialize in treating epp. she estimates there are fewer

than 500 diagnosed cases in the united states. though she believes many more are undiagnosed or misdiagnosed. there is no cure for epp which can be life-threatening. >> small percentage of patients will get liver failure, from the literature about 5% or so. >> the long-term implications of epp are still not entirely clear, but one thing is. once a full-blown reaction to the sun starts, it's extremely painful and can last for days. this video shows a young person with epp after too much sun. >> what's burning? >> she's in the bath trying to lessen her pain but it's not helping. >> you can't just take a tylenol? >> you cannot take a tylenol. even stronger pain medications don't really work for the pain. >> young brady knows all about that. for years he hasn't jumped into a sun-lit pool or dashed out onto the playground for recess.

>> do you remember what it was like when you didn't know and you stayed out in the sun? >> yes. it was not pleasant. because i didn't know what was happening. >> neither did brady's mom, kristen. >> i was thinking what the heck is going on with my kid? you go to the e.r. with someone who is writhing in pain but there's nothing visible. >> that's the thing with epp. there are often no visible signs during or even after a reaction, which makes epp even harder to diagnose. >> and it was actually his pediatrician that had referred us to a pediatric dermatology specialist. he had seen one previous case. >> how lucky were you that that doctor had happened to see another case? >> so lucky. >> every case of epp is different. brady feels the tingling and stinging coming on after less than a minute in the sun. but he can tolerate shade and wearing a thick, long-sleeved hoodie gives him enough

protection. >> we've seen him, he jumps from shadow to shadow. >> he does. he shadow hops. you walk out any door out of school, out of the car and there's always a line. here is the shade and here is the sun. and brady stops. he's always on lookout for the next safe place. >> safest place for brady, of course, is indoors. so, every day at school during recess, brady picks three friends to join him in the school gym. >> i feel bad for him because he doesn't get to do what like others get to do. >> does it ever bug you that you have to sit in the shade? >> sometimes. i wish i could just be like them, my friends. >> brady and mckenzie. their parents not only have to shield them from the sun, but also from the stares and pain of isolation that sometimes hurt even more. growing up with such little

light makes their future that much harder to see. it's a journey that will require more strength than creativity than these families ever imagined. >> coming up, is there a way to let these kids into the light? >> i was outside all the time with short sleeves. it was great, no reactions. >> a tremendous ray of hope when "dateline" continues. ♪ happiness is powerful flea and tick protection from nexgard. nexgard kills fleas and ticks all month long. and it comes in an easy-to-give tasty chew. and that makes dogs and owners happy. no wonder vets love it too. reported side effects include vomiting, itching, diarrhea, lethargy and lack of appetite. see your vet for more information on flea and tick protection you and your dog will love. nexgard. the vet's #1 choice. let's talk about haribo goaloha.s. i can't stop eating this orange one. the red one is more gooder to me

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because she has a condition called epp, mckenzie has to apply special sun block before she walks out of her house. she wears uv-resistant clothing and a hat even when she's inside since certain overhead lights can also cause a painful reaction in mckenzie. while her face shield is needed for prolonged sun exposure, mckenzie's special has has protected her every single day since she was 2. >> i'm the most embarrassed when we have to do the national anthem and i'm the only one with a hat on and i can't take it off and everybody stares and i'm like, oh, no. >> a few days before she started high school, mckenzie, shy already, had fears that even more kids would stare. but her mom had more concerns. she met with the vice presence pal to make sure the windows and lights were safe for mckenzie. >> i'm getting a one. what are you getting?

>> for extra protection mckenzie has a special chair with a canopy, but eating lunch in the sunlight on a bright warm day, mckenzie has never done that. >> if i could not go out in the sun, what is life? >> isn't the one girl -- >> she's allergic to it so she has to have special lighting. >> i would like to go outside and eat with my friends that are eating outside. unfortunately i have to stay in here. luckily some of my friends are very thoughtful and they stay in here with me. >> but when the sun goes down, mckenzie and her friends can go anywhere they want. shut out from the sunlight, boxed in all day, mckenzie finds her radiance at night. >> i make sure i have like a night wedding. >> she's more adventurous at

night. >> at home in bethesda, maryland, brady's life is similar. he, too, can play more freely after dark. >> throw it as hard as you can. >> i throw as hard as i can, i'm going to hurt you. >> please don't. but he doesn't seem to appreciate the night as much as mckenzie does. that's because brady would rather play in the daylight, and his mom, kristen, thinks there may be a way to bring him out of the shadows. >> all i want for my son is that some day he may be able to feel the warmth of the sun. >> kristen is hopeful. there's an experimental treatment out there designed to give people with epp temporary protection from the sun. the drug is afamelanotide, implanted beneath the skin increase skin pigmentation for two months. basically it would give brady a medicinal tan. >> a protected layer. >> like a coat of armor. >> great way of looking at it.

>> the drug hasn't been approved by the fda, kristen is telling her son about the treatment since it went through a drug trial in 2011. how does it make you feel inside when you think about the possibility of having a drug that could help? >> makes me happy. >> in epp's small community, brady's mom got to know a young man named andrew terrell who had the treatment for several months during that drug trial. he has been waiting for the drug's availability, too. >> i coached baseball that summer. i was outside all the time. there was no reaction. >> we arranged for him to speak with brady about the implant. >> how did it feel? >> it was great. so it was really easy to get. 20 minutes in the doctor's office. it works for two months. i got really, really tanned. >> does it hurt? >> when they injected it? >> yeah. >> it hurts for a couple of seconds maybe but so worth it. how did you hear about this new treatment? >> my mom told me.

when i get it, i can finally go in the sun for a while. >> the implant seemed to work for andrew, but it's never been tested for children. >> do you ever worry that even though the drug shows so much promise that maybe it wouldn't work in brady? >> i've never thought about that. haven't gone there in my mind. >> what if you're giving him false hope? >> that could be. that could be. i hope not. brady did a picture at school of a kid on a lounge chair and a huge sun in the background and the only words on it were hope. this is what he wants. >> this drug might help mckenzie, too, since she has brady's same condition. her mom, shannon, has a different attitude. she doesn't want her daughter to hold out hope for a treatment and certainly not for a cure. >> i don't want her to get her hopes up and then just never see that light at the end of the tunnel. i want her to live with it and

live healthy with it. >> she's taught mckenzie to know her limits, like on this foggy morning during pe, when mckenzie played for about 30 minutes with just her special hat and sunblock on. >> i was able to play soccer today because it was not too sunny and cooler this morning. >> but back inside, she knew her mom would want her to sit under that canopy. >> do you ever worry that maybe you're being too overprotective? >> i don't think there's any such word as that when you're a mother. i would rather be too cautious than not cautious enough. >> even if it means she has to wear a lot of gear and people point fingers? >> i would rather people point fingers at her for the next 50 years than her be sick. >> there is one place where no one points fingers, no one stares, where mckenzie and brady can feel like any other kid. a place full of life. in the dead of night. >> coming up -- >> it feels like i'm a normal person. >> and later --

>> the night is kind of special to me. >> her name is paris, and her struggle -- >> not to get morbid, but i could potentially die. >> life and death every day when "dateline" continues. as a control enthusiast, i'm all-business when i travel... even when i travel... for leisure. so i go national, where i can choose any available upgrade in the aisle - without starting any conversations- -or paying any upcharges. what can i say? control suits me. go national. go like a pro. and sometimes, i don't eat the way i should. so, i drink boost. boost high protein nutritional drink has 15 grams of protein to help maintain muscle and 26 essential vitamins and minerals, including calcium and vitamin d. look for savings on boost in your sunday paper.

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but at this camp in upstate new york, the only sound came from the wind and the trees. but inside, we found them. chatting in the hallways. taking a nap. one kid was still in bed at 11:00 am. though they had legos to build and pictures to draw, it often seemed they were just killing time until, finally, the stars came out and the moon watched over them. this is a camp for kids who can't be outside during the day, can't play in the sunlight. a camp where everything glows. where the lakes are as dark as the night, and brady jumped right in. camp sundown started more than 20 years ago by parents of a

child who also couldn't be in the sun, flips the world upside down. kids play when they should be in bed, sleep when they should be outside. no one here gets a lot of rest. mckenzie flew almost 3,000 miles to be here. >> i like to come out and play softball. it's really fun. >> it was here where brady realized for the first time that he wasn't alone in the dark. >> it feels like i'm a normal person. >> it was close to 2:00 am when the campers were coming back from a field trip. >> i didn't think the fireworks show would be that good, but it was really good. >> while mckenzie and brady have epp, many here have different illnesses that make them sensitive to the sun. the camp welcomes family members, too, like mckenzie's twin brother, dawson and brady's two older brothers.

when the sun comes back up, every kid at camp has to go back inside. >> i had one wish, i would probably want to stay at camp sundown forever with all my friends. >> kids here say the best thing about camp is that everyone gets it. so when one camper talked about wanting to play football for his school one day, it became a conversation that could only happen here. >> my doctor said no, but i'm going to do it anyway. >> you know, if you crack your helmet, the sunlight could go through that and right into your face. >> remember that visor i wear? >> yeah. >> i could take an old one of those, stretch it out and put it under it and tape it so it will cover up the little slits. >> i wouldn't take the risk. >> kevin, that's you. i just want to play sports wherever i go. >> when camp was over, mckenzie was back in her face shield, back in the harsh reality of the

daylight as she headed home. her mom, shannon, recalled one time at the airport when a group of people just wouldn't stop staring at mckenzie. what did you say? >> i just said how dare you? it's rude. it's rude and it's ignorant. she has a condition and if you had any class, you would ask instead of pointing. those are the days i wish i could trade places with her, in a heartbeat. >> shannon says her shy, quiet daughter would rather hide behind her shield than talk to people about her condition. she thinks mckenzie needs to learn how to speak up for herself. >> her father and i won't always be there to explain or to help people understand. that's why i tell her it's important to find her voice. >> while mckenzie was trying to find her voice, brady, back home with his mom in bethesda, was still dreaming about this vision and waiting for that experimental treatment that could make being in the sun a

reality. >> it's his hope. i let him have that hope that some day he will get to lead a normal life without this struggle. >> while children with epp do struggle, there's another disease out there that's more serious, more deadly. for this young girl named paris, every drop of sunlight that touches her skin is a matter of life and death. >> i don't think people understand the severity of it. not to get morbid, but i could potentially die. >> going out at night is the easiest way for paris to avoid the hot desert sun of st. george, utah. that's where her family's remarkable story begins, a journey with twists and turns that no one could have anticipated. >> we had to flip things upside down. >> jennifer and todd feltner's dream was to have a large family. their first child was parker and then came paris, two years later.

she was an adorable baby. but at 6 months, she had freckles. >> we went back for the 9-month checkup, and that's when the doctor said there are more and they're darker. >> they were referred to a specialist. >> we were looking things up in books. they were calling people on the phone. and the longer we sat there, the more our hearts dropped. >> then finally a diagnosis. >> paris tested positive for xp. and that's the last thing i heard. >> xp is xeroderma pigmentosa. >> dr. barry cunningham has been treating the rare disorder for years says any one of us can get skin cancer. in fact, one in five of us will. but for paris, who had to wear this full bodysuit after she was diagnosed as a baby, the odds are much worse. she lacks the enzyme that repairs dna damage caused by sunlight every day. that means she's 20,000 times more likely to develop cancer when unprotected.

>> if you have a kid who is wearing a hood and some joker on the playground comes over and rips the hood off as a joke, can that damage in just a couple of minutes -- >> yes. >> -- cause cancer? >> yes. absolutely. >> when children with xp aren't protected early, the consequences are severe. >> oh, my goodness. >> dr. cunningham showed us photos of some of her young patients in guatemala, disfigured from numerous skin cancers. >> oh, my goodness. it's hard to look at. >> i really felt like it was a death sentence and she would be lucky to live into her teens. >> shielding paris from the bright utah sun was the only way to save her. but, believe it or not, that was only the first of many challenges this family would face. >> one child with a deadly condition. would they risk having another? >> coming up -- >> they tested. >> and another.

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i'm gigi stone woods with the top stories. the u.s. state department is monitoring claims that government forces launched a deadly chemical attack on civilians in eastern gu at that. the charity group white helmets is reporting up to 40 killed. a crash between a truck and a bus carrying a hockey team in canada has risen to 15 have died. it was carrying the humboldt broncos. a junior hockey league. now, back to "dateline." welcome back to "dateline." i'm craig melvin. children with verve and life-threatening sun sensitiv y

sensitivities have to make big adjustments, as the parents of paris felton found out, their struggle was about to multiply. >> like lots of young women, paris loves to shop. >> hold that up. >> she says she could spend hours in a mall. but when a sidewalk sale brings her outside, we're reminded why paris is forced to think differently. because she has xp, paris has to protect herself from sunlight. >> i really do feel like the odd one out when everybody is in their shorts and t-shirts and i'm sweating to death. >> her hood may be uncomfortable to wear on a hot, sunny day in utah, but it's clear uv-resistant plastic is a huge breakthrough for people with xp and a big improvement from that first suit she had to wear. but when we last sat down with her, paris said wearing that hood has gotten

harder for paris as she has gotten older, especially with all the social pressures of high school, dating and dances. >> someone has told me that like i'm ugly in my hood. >> someone said that? >> it hurts really bad because sometimes i do think that. >> but no matter how self-conscious she feels, paris knows how dangerous it would be to take off her hood. >> anything that you notice on your skin? >> she sees a dermatologist at least twice a year to check for skin cancer. >> on my nose, can you see that? >> yeah. >> on this visit, it was nothing serious. but when paris was 8 she felt a bump on her head. she was so frightened of going to the doctor that she didn't tell her mom about it for weeks. >> i was so scared. i was so scared. if i would have left it for a long time, it could have spread. >> it turned out to be melanoma, the most deadly skin cancer. though it was successfully removed, the scare made paris even more vigilant. >> my friends that i've known for years, they don't understand

that if i did not wear my hood, i could die from skin cancer. >> having a child with such a serious disease made it hard for jennifer and todd to think about having another child. and they didn't, for five years. but as they saw paris thriving as a young girl, despite her limitations, they began to think again about their dream of a big family. >> i don't know. we just -- we always knew we wanted more than two. >> the couple got advice from a geneticist. since both mom and dad carry a defective recesssive gene, the doctor said their children have a one in four chance of having xp. >> basically you have a 75% chance of not having another one with xp. >> but you have a 25% chance. >> 25% chance. >> that your next baby is going to have the same thing. >> yeah. so we had to be prepared. >> when paris was 5, jennifer and todd, devout mormons, decided to have another child. >> i had prayed and i had felt like my answer was everything is

going to be okay. >> she had a boy named paxton. and at birth, he tested positive for xp. >> i did go through a time where i said, i did this to him. you know, it was. it was a feeling of guilt. i have to say that i was pretty mad at god for a little while. it tested my faith. >> jennifer knew she would be tested every day. now with two of her three kids with xp, she decided no more children. >> three was good and we were happy and then todd came to me and he said, we need to have another baby and i said oh, my gosh, you're crazy. no! >> i'm an accountant. i think analytically. i thought, okay, we have two. i just don't think we'll have another child with xp. >> oh, okay. well, here we go again. >> nine months later, peyton was born.

their fourth child. and they had him tested immediately. the doctor called with the results. >> he said, i can't believe that i have to tell you this. and i said well, you don't even have to say it now because i know. >> peyton also tested positive with xp. >> and i just sobbed. and i just couldn't believe it. >> did you think a lot of people are going to hear your story -- >> yeah. >> -- and think, why? >> are you stupid? yeah. >> what do you say? >> i say you have to meet my kids. >> growing up with xp together, paxton and peyton were inseparable, spending hours in an enclosed playground off their basement. >> you and your brother are so close in age, do you do a lot together? >> yeah. bee we do a lot together. it was kind of like oh, i have two buddies. >> paris and peyton. >> yeah, paris and peyton. >> it was then that jennifer and todd chose surgery in order to prevent another pregnancy.

>> i thought okay, i'm done having kids. i'm going to get my body back in shape and just couldn't get that belly to go away. and then the thought hit me -- oh, it could not be. coming up -- more news from the doctors and no one can believe it. >> i've had this for five years of my life and now you tell me? >> a life-changing moment for all of them when "dateline" continues. flea and tick protection from nexgard. nexgard kills fleas and ticks all month long. and it comes in an easy-to-give tasty chew. and that makes dogs and owners happy. no wonder vets love it too. reported side effects include vomiting, itching, diarrhea, lethargy and lack of appetite. see your vet for more information on flea and tick protection you and your dog will love. nexgard. the vet's #1 choice.

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after three of their four children were diagnosed with xp, a deadly genetic disease that forces their children to avoid sunlight, jennifer and todd feltner said they were done taking risks. >> we should not go to vegas. our odds -- we don't roll the dice well. >> but despite taking measures to avoid a pregnancy, jennifer discovered she was carrying a baby yet again. though there was a 75% chance that her child would not have the disease, jennifer was almost resigned to her family's extraordinary bad luck. >> just have him tested at birth, and this time we got our 75% chance, and he didn't have it. >> no xp? >> no xp. >> this is their youngest child, porter, who loves to laugh. but astonishingly, the world of the feltners would flip over yet again.

national institutes of health asked the feltners to come to their headquarters so the doctors could study their unusual family, with three kids with xp. at that point paris was 13, paxton was 8 and peyton was 5. >> they do all sorts of tests. >> shortly after they returned home, the doctors discovered something unexpected. they ran more tests and called the family with some incredible news. >> and they said peyton does not have xp. >> does not? >> peyton, the third child diagnosed with xp was actually misdiagnosed at birth. >> as crazy as it seems, it's another devastating day. >> he does not have xp? >> right. he does not have xp. >> why is that devastating? >> you would think that he would be so happy, but i'm going to have to tell two of my children that they're not the lucky ones. >> jennifer and her husband

decided to tell the two that had xp first, paxton and paris. paris cried. paxton worried he lost his best friend to the daylight. >> i felt like we're not going to get to do a lot of things together anymore because he's going to be outside. >> then they told peyton, who was just 5 years old at the time. >> i was like, i've had this for 5 years of my life and now you tell me i don't have it? >> so we said, do you want to go outside? he said, okay. >> and my friend was playing right over there. he yelled at me and he said, peyton, what are you doing? you don't have your hood on. i know! i don't have xp anymore. feeling like shocked, kind of scared and happy. >> it was scary? >> yeah, it was scary. >> because that was all you ever knew. >> yeah, really, that was all i ever knew, was to stay out of

the sun. >> this is a disease that has no cure. and yet you are maybe the closest anyone has ever come to having a child cured. >> yeah, yeah. yeah, you're right. >> the whole family was watching this magical scene of peyton playing openly in the sun for the very first time in his life. everyone except one person. >> i thought i could do it. you know, i thought i could stand there and watch him. at the last moment i just couldn't take it. so i just slipped out and went to my room and started crying. i know how awful it can be to have this disease, you know. so i was so happy that he was able to play baseball. he's able to run out with his friends. he's able to, you know, do all the things that we aren't able to do. but then i was sad because it wasn't me. it kind of hit me that, oh, i'm stuck with this my whole life. >> a lot of times when i was little, i would dream about

being out in the sun, you know. run and play with my friends outside in the daytime. but now i don't really dream about that. >> once in a while, paxton says he still feels a little bummed about peyton's new life in the sun. >> i miss having a brother that has xp. i'm happy for him. >> when he says that stuff, it kind of makes me like want to have xp, but i don't wish i had xp. it feels kind of -- >> kind of guilty? >> yeah, guilty a little bit. >> paxton used to wait for the sun to go down with his brother but now he waits alone. >> what's it like to sit here and kind of wait? >> you get really bored. and you just wish you could go out right now. >> without protective gear on, paxton can't safely measure the intensity of the sunlight himself. so i checked it, using his light meter. ten or below is safe for him. hey, paxton, it's seven. >> all right. >> that's really good, right?

>> yeah. >> now it's a six. >> though he would rather have this freedom all day, paxton enjoys having a special time to look forward to. >> i'm seriously getting dizzy now. >> his older sister was thinking about a special time, too. one that most high school girls dream about. the prom. but she was worried. your mom said that someone once said to you that you would never go to prom. >> yes. this person was a boy, and that's hard to hear from a boy, because i think about boys. not that i'm all that boy crazy, because i'm not. it kind of lurks in my mind like, oh, you'll never get asked to a dance. >> for paris, the social pressures are mounting, just like they are for mckenzie, the quiet one from canada, and brady, still dreaming of a magic pill that will let him play in the sun. but will it ever be within reach? coming up -- >> are you in central park?

>> i'm actually outside in the sun now. >> brady, mckenzie -- >> everybody was listening. >> they were all listening, weren't they? >> paris. >> have some exciting news. >> they all have something to share when "dateline" continues. ♪ protect your pets from fleas and ticks with frontline plus for dogs and frontline plus for cats. its two killer ingredients work fast and keep working all month long preventing new flea infestations on your pet. frontline plus. the number 1 name in flea and tick protection. claritin and relief from of non-drowsy symptoms caused by over 200 allergens. like those from buddy. because stuffed animals are clearly no substitute for real ones. feel the clarity and live claritin clear.

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because being exposed to the sun can cause serious harm,

brady, mackenzie and paris were three kids doing their best to live a daylight-free life. but would any of them find that just maybe they would be able to come out of the shadows? here with the conclusion of our story is cay stone. >> in 2015, brady and mackenzie spent time at school the way most kids do, hanging out with friends and looking toward to summer carp, but with one difference, avoiding the sun. because sunlight exposure can cause a painful reaction in kids with epp, brady was still hoping for that experimental drug, the one that would darken his skin and make it more resistant to sunlight. do you think one day you'll be able to get that medicine? >> yeah. >> and then brady and his mom heard some encouraging news. the drug was finally approved in december 2014 but in europe. >> it opens a door that had not been opened before. so, it's amazing.

>> the drug still wasn't available for kids. >> welcome to terminal four. >> she was delighted to find out that their new friend, andrew terrell, was getting on a flight. >> i'm heading to switzerland. i'm very excited to get back on the treatment. >> when andrew was part of a drug trial, each treatment protected him for two months. it worked so well, he didn't think twice about traveling 4,000 miles to zurich to get another implant. >> are you okay? >> totally painless. >> two weeks later, kristen and brady received a skype call. >> i hear you went to switzerland. >> i got a drug treatment. yeah. it's great. i'm actually out in the sun now. >> are you in central park? >> yep. i'm right here. lots of people out enjoying the day. >> do you want to ask him if he thinks you should do it some day? >> should i do it some day? >> absolutely. as soon as you have the chance. i'm hoping it comes to the states soon. >> in 2016 the drug got a

fast-track from the fda but it is not approved. but since there's no guarantee that the drug will ever be developed for pediatric use, brady was looking forward to one special birthday, his 18th. >> i let him do a countdown. i hope it was really good for him to see what can be for him. >> on the west coast of canada, shannon was also thinking about her child's future living with epp. she sometimes is concerned about mackenzie's extreme shyness. >> it definitely made it harder for her to come out of her shell. >> so it was a big day at school when mackenzie decided to do something the thought she could never do. speak in front of her whole class. >> most of you guys know me. but if you don't, i'm mackenzie and i have epp, which means i'm allergic to the sunlight and ultra violet light. there's a canopy on my chair

that protects me from ultra violet light in the room so i can stay here. >> it was the first time she gave a speech about what she has and who she is. she did it to raise awareness about camp sundown. >> and we do fun activities only at nighttime. and the mosquitos are really bad there, but if you want to know more about the camp you can check online. if you have any questions for me, i would be happy to answer them for you guys. it wasn't as bad as i thought it would be like. everybody was listening and i didn't think they were going to. >> they were all listening, weren't they? >> uh-huh. >> i think that's what your mom is talking about when she says that you're going to find your voice. >> i'm so happy that she is finding it. because that's the hard part. >> the limit takeses -- limitations she has, they don't

stop her from doing anything. she does things differently and does them mostly at night. >> i love the night because i can watch all the stars. >> we should probably get off the middle of the road. >> in fact, mackenzie says she's adapted so well to her limitations that she rarely thinks about having a cure one day. >> i know how to deal with it, so it's all good. >> for paxton, living in utah with a more serious disease, the cancer-causing xp, there is no cure. no breakthrough treatment. and when his younger brother, peyton, found out four years ago that he was misdiagnosed as having xp, paxton thought the sunlight had taken away his best friend, too. >> i can't go to some of his games. i just go to the night ones. it was hard at first. now i've gotten used to it. >> i said you know what it was like firsthand to live with xp. and after you've played outside with your friends all day and it finally gets dark and paxton can go outside, i want you to make yourself go outside. there have been a few times when

he has been watching tv and he has been outside and i'll say, peyt. and he'll say, i know, mom. i'll get my coat. >> dr. cunningham thinks a cure for xp is possible some day. >> patients of xp are missing an enzyme. it's completely plausible that that enzyme could be created and applied to the skin. i'm extremely optimistic that in my lifetime there will be a cure. >> paxton and peyton's sister, paris, now a high school junior, also hopes for a cure. it hasn't been the first thing on her mind lately. she was still wondering if someone would ask her to the prom. >> sometimes i just think, what if somebody doesn't want to ask me because i have xp? >> and then one day, paris got her answer. >> i have some exciting news. i got asked to junior prom the

other day. and i'm really excited about it. i think it's going to be a great time. >> i'm in love with this dress so much. >> i think it makes me feel a lot more normal just because it's something that everybody else does and it's something that i can do that everybody else does. because i can get dressed up. i can, you know, go on a date like a normal person. >> you're not nervous at all, are you? >> just a tad. >> i think that if i can make these adjustments and do when i need to do to make myself safe -- >> no, no, not yet. >> it's a good indicator that i can deal with the changes and roll with the punches. >> i metered outside. it's a 25. so she is going to have to wear her hood to get out to the car. >> i think i'm going to just

kind of not stress about something that doesn't need to be stressed about right now. >> why stress on tomorrow when tomorrow hasn't even come? >> did you see her when she went to the prom? how did she look? >> she looked beautiful. >> you would never recognize that she has xp. >> yeah. for real, though. >> these kids all hope for a brighter future, but look around at where they are now and you realize, they're already in a special place that's just as bright. that's all for this edition of "dateline." i'm lester holt. thanks for watching. good morning. i'm gigi stone woods in new york at msnbc world headquarters. it is 7:00 out east, 4:00 out west. here's what is happening. breaking news out of syria where the state department is monitoring reports of a chemical attack that may have killed dozens. we'll have the latest. and a deadly fire in trump tower in new york. details on where the first family was when the flames broke out. and is john kelly coming undone? new reports of the chief of staff blowing up,