Histidinuria due to renal tubular defect
Incidence
The inheritance is presumably autosomal recessive. Only 5 patients reported, all males.
Clinical Characteristics
Sabater et al. (1976) described 2 brothers, aged 9 and 11 years, with mild mental retardation and histidinuria despite normal blood levels. Histidine loading showed impaired intestinal absorption. The inheritance is presumably autosomal recessive because both parents showed intermediate intestinal absorption. Holmgren et al. (1974) had reported 1 patient with renal histidinuria associated with myoclonic seizures. Kamoun et al. (1981) likewise reported 1 patient with associated histidinuria and myoclonic seizures. Nyhan and Hilton (1992) described a 7-year-old boy with histidinuria without histidinemia. Low concentrations of histidine in plasma were consistent with impaired intestinal and renal tubular absorption of histidine. The patient was developmentally delayed and had some minor anomalies: bilateral nerve deafness of moderate severity; protuberant large and somewhat simple oracles; very short thick fingers and toes with hypoplasia of the toenails; and broad nasal bridge with long shallow philtrum and thin upper lip. Roentgenograms showed that the shortness of the 5th digit resulted from a short rounded middle phalanx that was abnormal in shape. All 5 patients who have been reported have been male.
Precipitants
none.
Provocation Tests
None.
Diagnostic Procedures
There is Histidinuria with low Histidine serum levels.