jubears09 t1_ja9kp9y wrote
Reply to comment by AbouBenAdhem in Is there a genetic disease where the heterozygote has more severe disease symptoms than the homozygote? by Altranite-
Sort of. Protocadherins are like address codes in the developing brain. So the problem is having 2 different sets of instructions for migrating neurons. Hence heterozygotes have disease and homozygotes (even if mutant) are normal. even if co-expressed absent mosiacism the prediction would be disease. However, for reasons I mentioned in the original post human examples would be hard to find because the event of 2 identical yet independent mutations would be highly improbable.
In diseases with recurrent mutations there is usually a mechanistic reason (Gain of function in achondroplasia) that wouldn't apply here.
Here is an even older paper describing this before we found any examples.
Droopy1592 t1_jaa720x wrote
This is so damn interesting. I would have never seen anything like this in my normal studies. I never would have thought heterozygous could be worse.
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