osteogenesis imperfecta is rare. it's also called oi. affecting between 25 to 50,000 americans, with various degrees of severity. hannah's condition is among the serious. >> do you think your body is used to the pain? >> no. >> sometimes they hurt. can you describe what the pain is like when it's bad? >> on a scale of one to 10 it was off the scale. like 40. >> this doctor is one of the top paediatric specialists and showed us how the disease ravaged hannah's body. here in happena's leg the knee is here, this is the middle of the tibia fractures healed here. my whole career i try to straighten crooked bones. it's frustrating that hannah we have not been successful. it's the bone disease that defeats us. it's a challenge and is frustrating. >> what is it about hannah that you find special. >> hannah has a bright spirit. ? if any one of awes was in her black of us was in her situation, we would be negative. she is bright, cheery, accepts her fate and moves on. >> the outside world can be a scary place for hannah, a crack in the sidewalk or

i featured her in a report about the rare disease, osteogenesis, brittle bones. >> first time we met, you were like six. now, hanna is growing up. she is 13 years old with the same vibrant spirit and an unforgettable laugh. >> but sadly, hanna's condition has not gotten better. she has suffered more than 126 bone fractures from things as simple as bumping into a wall or just rolling over in bed. >> make it quick. >> on this day, she is getting a check-up on her broken arm. >> osteogenesis imperfecta, called oi, is extremely rare. affecting between 25 to 50,000 americans with various degrees of severity. hanna's condition is among the most serious. >> do you think your body has just gotten used to the pain? >> no. >> no? sometimes they really do hurt? >> uh-huh. >> can you describe what the pain is like when it's bad? >> on a scale of 1 to 10? >> yeah. >> like off of the scale. like 40. >> hanna banana, how are you? >> dr. hersenberg is one the the top pediatric orthopedic specialists. he showed us how the disease has ravaged hanna i had boy. >> body. >> the most obvious example is the

. >> reporter: while hannah has brought some attention to osteogenesis, it's ignored in the scientific community. they have a small annual budget. >> what are the challenges that you have? >> i think that the challenges relate to research. >> reporter: every year hundreds of families with oi request help, but resources are stretched thin. >> how often do you have to say know because you don't have enough money? >> unfortunately, we are to say no a lot. we would like to have millions of dollars every year, somebody said i can't get out of my house because i don't have a ramp, and we would like to do everything. >> reporter: despite optimism that some like hannah can be cured, every day challenges are the reality, both physically and emotionally. >> some people scare me, and some say baby, and the kids say i'm a baby, and mom has to tell them, no, i'm a teenager, so it's weird. can't you see i'm not one? >> i know you're hungry, come on now, you know better. >> reporter: shortly after this exchange, the normally cheerful hannah asked us to stop the interview. >> you are tearing up, why?