<unk> , also called cystathionase deficiency, is an autosomal recessive metabolic disorder. It is characterized by an abnormal accumulation of plasma cystathionine leading to excess cystathionine in the urine. Hereditary<unk>  is associated with the reduced activity of the enzyme cystathionine gamma-lyase. It is considered a biochemical anomaly. This is because it associated with a wide range of diseases and its inconsistency. Cystathionase catalyzes cystathionine to cysteine and α-ketobutyrate. Cysteine is an essential amino acid and its conversion from cystathionine occurs in the trans-sulfuration pathway. The availability of cysteine is necessary for the synthesis of an important anti-oxidant, glutathione. Cystathionase has a co-enzyme, pyridoxal phosphate, which is the active form the vitamin B6. This means that vitamin B6 is essential for the function of cystathionase.<unk>  can be broken down into two main categories. Primary<unk>  is caused by the recessive inherited deficiency of cystathionase enzyme. Secondary<unk>  is described by non-genetic conditions of excess cystathionine. Secondary<unk>  includes temporary excess cystathionine of premature infants, severe generalized liver damage, thyrotoxicosis, hepatoblastoma, or neuroblastoma. Cases of secondary<unk>  are not responsive to vitamin B6 administration.
Cystathioninuria
Hawkinsinuria
Orotic aciduria
Aspartylglucosaminuria
Urocanic aciduria
Alkaptonuria
Alpha-aminoadipic and alpha-ketoadipic aciduria
Tyrosinemia