Cystathioninuria, renal iminoglycinuria and α ₁-antitrypsin deficiency in the same family: relevance in medical practice

Cystathioninuria, a benign condition, has been reported in association with other Mendelian disorders. Renal iminoglycinuria is either a transient normal finding in the newborn or a persistent benign inborn error of amino acid transport. The gene frequency for the latter is about 1.0% in the general population and probably higher among Ashkenazi Jews. While inherited α ₁-antitrypsin deficiency is prevalent and the frequency of the various α ₁-antitrypsin alleles usually exceeds 1.0% in many populations, the adaptive significance if any, of this genetic polymorphism is still under investigation. Meanwhile with a knowledge of Mendel's laws and with access to published data on the clinical significance of the 3 mutations observed in this family, we have been able to offer the family specific useful information during genetic counselling.