Under primary<unk> , the inherited mutation of<unk>  gene, there are two forms. There is vitamin B6 – unresponsive and vitamin B6 – responsive<unk> . The vitamin B6 – unresponsive form is thought to be from a lack of the synthesis of cystathionase. This means that the mutation in<unk>  from this form of<unk> , results in the absence of cystathionase. It could also result from the synthesis of a cystathionase that is so greatly mutated it cannot function at all. On the other hand, vitamin B6 – responsive form still has synthesis of cystathionase. However, the cystathionase has an altered ability to bind to vitamin B6, its coenzyme. This changed interaction lowers the efficiency of cystathionase, so it cannot convert cystathionine as well.
Cystathioninuria
Hawkinsinuria
Orotic aciduria
Aspartylglucosaminuria
Urocanic aciduria
Alkaptonuria
Alpha-aminoadipic and alpha-ketoadipic aciduria
Tyrosinemia