3 ms·

From farther down in the article: "'I’ve seen 700 patients with FOP around the world, and it’s clear that there’s a lot of different ways to divide patients,' K

From farther down in the article: "'I’ve seen 700 patients with FOP around the world, and it’s clear that there’s a lot of different ways to divide patients,' Kaplan said. One identical twin might be only mildly affected, while the other would be trapped in a wheelchair. Some patients developed a frenzy of bones as children, and then inexplicably stopped. 'I’ve seen it go quiet for years and years.'" Wow. That's an important clinical clue, that discordance between identical twins. That suggests that the disease is not best described by a single-gene mutation, strong expressivity http://www.nature.com/scitable/topicpage/same-genetic-mutation-different-genetic-disease-phenotype-938 http://www.nature.com/scitable/topicpage/same-genetic-mutati... simple Mendelian model. And that means that there is something else going on in the clinical expression of the disease besides the gene mutation, which might provide some traction for effective treatment. The last part of the article sums up some interesting ways that insights from rare disease research can help physicians better understand human physiology and perhaps come up with ways to treat more common diseases. A very interesting read.

caycep 13y ago
Yes - I think people refer to this as penetrance. I.e. there may be an overall inheritance pattern but additional factors (environment, additional genes, exposures) are needed to cause the expression of the abnormal gene. A lot of conditions are autosomal dominant but incomplete penetrance, and researchers can roughly quantify the percent penetrance of specific conditions.
fallous 13y ago
It could also be difference in circumstance. Note that the bone growth occurs as a response to muscle damage, so a more active child who suffers a higher incidence of standard bumps and bruises would be more likely to have more ossification.

caycep 13y ago

Yes - I think people refer to this as penetrance. I.e. there may be an overall inheritance pattern but additional factors (environment, additional genes, exposures) are needed to cause the expression of the abnormal gene. A lot of conditions are autosomal dominant but incomplete penetrance, and researchers can roughly quantify the percent penetrance of specific conditions.

fallous 13y ago

It could also be difference in circumstance. Note that the bone growth occurs as a response to muscle damage, so a more active child who suffers a higher incidence of standard bumps and bruises would be more likely to have more ossification.