Accidental_Ouroboros

Odd, but it may be that your case is one of the ones not generated by the gene variants endemic to Asian populations, or it could be a one-off (de novo) mutation.

Also, the great-uncle that died, was he on your mother's side or your father's side? The disease itself seems less genetically penetrant in females than males, but if on your father's side, he might want to get checked out if he has not already - he could have a lower-grade version of it, as the disease is generally autosomal dominant.

This is one of the things I distinctly remember reading about in cardiopathology in medical school, and I am very glad that it was caught before you had a cardiac event. Along with undiagnosed congenital cardiac abnormalities, this is one of the big reasons behind trying to get AEDs installed in as many schools as possible.

Now for a question: We were primarily taught that this was most common in Asian populations. You look Caucasian in the picture, do you happen to have any Asian ancestors?

For PKU, it is more a question of phenylalanine over time.

For instance, if untreated, most babies seem normal for the first few months of life, but start to suffer serious neurological issues (seizures, intellectual disabilities, etc) at around 6 months.

The reason for this is that there is a secondary, minor pathway (a transaminase pathway that converts phenylalanine into phenylacetate, phenylpyruvate and phenethylamine) that can take care of a small amount of Phe. With a normal diet in a person with PKU, it simply can't work quickly enough to get rid of all the phenylalanine that they eat - so it builds up.

So, in reality, it is all a question of intake vs. how quickly you can convert it via the minor pathway. That is a big reason why different PKU patients can deal with different levels of phenylalanine - for some individuals the minor pathway is more robust, and they get a bit more leeway.

As in: One extra dose of protein in an adult is not going to kill them, but the whole thing is a balancing act: It means they have to make sure they take in less phenylalanine elsewhere to compensate.

Eunuchoidism, essentially. He may be that tall (at least in part) because of the lack of puberty. Although the growth spurt in the early teens happens at the same time as puberty, it is not strictly speaking driven by puberty. In fact, puberty leads to the closure of the growth plates at the ends of long bones. Though if he is on meds now, those growth plates will close. He might still get a bit taller before that happens though.

It is actually a classic result of several diseases that lead to a failure to undergo puberty.

Nope - torn urethra. That is internal damage.