NeurometPlus

Incidence

It is an autosomal recessive phenotype. Screening surveys of neonatal urine samples have estimated the prevalence of cystathioninuria at 1 per 14,000 live births.

Clinical Characteristics

Cystathionuria is an autosomal recessive disorder due to cystathionine gama-lyase deficiency. It is usually pyridoxino-dependent, but in very rare cases it may be non-dependent. Clinical presentations are variable, ranging from mental retardation to asymptomatic. As a result there is a debate as to whether the disorder is pathogenic or not. Screening surveys of neonatal urine samples have estimated the prevalence of cystathioninuria at 1 per 14,000 live births. The defect involves cystathionase that does not properly bind its coenzyme, pyridoxal phosphate. In vitro studies suggested that high pyridoxine would be therapeutically beneficial. Some patients with abnormal findings have been reported. One was a severely retarded female, aged 64 years at the time of study. Another case was studied at The New York Hospital. Other clinical manifestations have been clubfoot, developmental defects about the ears, convulsions, and thrombocytopenia. Urinary lithiasis also occurs. In summary, cystathioninuria, an autosomal recessive phenotype with no striking pathologic features, is characterized by abnormal accumulation of plasma cystathionine, leading to increased urinary excretion. Because of the inconsistency and wide variety of disease associations, cystathioninuria is considered to be a benign biochemical anomaly.

Precipitants

None

Provocation Tests

None

Diagnostic Procedures

Urine and plasma aminoacid quantitative measurement show abnormal accumulation of plasma cystathionine, leading to increased urinary excretion.