inheritance.<unk>  is inherited in an autosomal recessive manner. This means the defective gene responsible for the disorder is located on an autosome, and two copies of the defective gene (one inherited from each parent) are required in order to be born with the disorder. The parents of an individual with an autosomal recessive disorder both carry one copy of the defective gene, but usually do not experience any signs or symptoms of the disorder. Interestingly, homozygotes and heterozygotes were able to be distinguished in one study through both plasma and urinary levels of cystathionine. The homozygote individuals had cystathionine levels greater than 0.5 moles per milligram of creatinine. Each of the homozygote individuals had a significant amount of cystathionine in the plasma as well. In contrast, the heterozygote individuals excreted approximately one tenth the amount of cystathionine as the homozygote individuals. The heterozygote individuals also had no detectable amounts of cystathionine in their plasma. The gene for cystathionase,<unk> , has been sequenced and multiple mutations have been shown to be associated with the development of<unk> . Two nonsense mutations were found in exon 8 and exon 11 of<unk> . Two missense mutations were also found, mainly in exon 2 and exon 7. In addition, a common non-synonymous single nucleotide polymorphism in exon 12 was also identified. The presence of various<unk>  mutations is consistent with the various categories associated with<unk> .
Cystathioninuria
Hawkinsinuria
Orotic aciduria
Aspartylglucosaminuria
Urocanic aciduria
Alkaptonuria
Alpha-aminoadipic and alpha-ketoadipic aciduria
Tyrosinemia