Iminoglycinuria.
Incidence
Autosomal recessive. Very rare. May not have clinical relevance.
Clinical Characteristics
It is a benign inborn error of amino acid transport. The imino acids, proline and hydroxyproline, share a renal tubular reabsorptive mechanism with glycine. Iminoglycinuria occurs as part of the generalized aminoaciduria of the Fanconi renotubular syndrome. It also is a normal finding in neonates and infants under 3 to 6 months of age. Iminoglycinuria may be more frequent in Ashkenazim than in others. Further heterogeneity is suggested by description of associated mental retardation (Statter et al., 1976). Saito et al. (1981) described atypical gyrate atrophy in a 44-year-old woman whose parents were first cousins and who showed strikingly increased urinary excretion of proline, hydroxyproline, and glycine. They suggested that the occurrence of gyrate atrophy with ornithinemia (258870), together with this observation, indicates that proline deficiency in chorioretinal tissues may be the mechanism of gyrate atrophy. The deafness associated in the case of Rosenberg et al. (1968) and the blindness in the cases of Tancredi et al. (1970) and Fraser (1971) were probably coincidental associations related to the populations screened.
Precipitants
None
Provocation Tests
None
Diagnostic Procedures
Aminoacids in urine quantitative. Iminoglycinuria also is a normal finding in neonates and infants under 3 to 6 months of age.