Benign inborn error of metabolism caused by a defect
in renal tubular amino acid transport resulting in abnormal urinary
excretion of glycine, proline, and hydroxyproline.
Homozygotes: 1:15,000 live births; heterozygotes: 2:100
in the general population.
Usually autosomal recessive, heterozygotes may
be “hyperglycinuric” (incomplete recessive), or silent (completely
Benign condition in which glycine and the imino
acids proline and hydroxyproline have a decreased renal tubular
reabsorption. Results from a specific inborn error of metabolism involving
the common membrane carrier of these amino acids in the renal tubule.
Individuals with familial iminoglycinuria are
asymptomatic. Excessive urinary proline, hydroxyproline, and glycine are
normal findings in the first 6 months of life. In iminoglycinuria, urinary
glycine excretion exceeds 150 mg in 24 hours, or endogenous renal clearance
rate exceeds 8.6 ml/min/1.73 m2.
No specific precautions required for
Chesney RW: Iminoglycinuria, in Scriver CR, Beaudet AL, Sly WS, Valle D:
The Metabolic and Molecular Bases of Inherited Disease. 7th ed. New York, McGraw-Hill, 1995, p 3643.