Lysinuric protein intolerance, an autosomal recessive disease

Lysinuric protein intolerance (LPI) is characterized by failure to thrive, diarrhea and vomiting associated with protein intake, aversion to protein-rich food, growth retardation, hepatomegaly, hyperammonemia, and deficient urea formation after an amino nitrogen load, and increased urinary excretion of basic amino acids, especially lysine. LPI has been diagnosed in 16 patients of 10 families in Finland and in one Finnish immigrant in Sweden. In this study data were evaluated to test the autosomal recessive transmission of LPI.
In 6 families out of 10 the occurrence was familial. The sex ratio of those affected was 6 : 10. The proportion of affected sibs, corrected by Apert's a priori method, was 0.26. In 5 families the parental marriage was consanguineous, and in two groups of two families all four parents were descendants of one ancestor pair. The geographical distribution of the LPI ancestors was uneven as is true for many rare recessive diseases in Finland. No heterozygous effects of the LPI gene could be detected with certainty. These finclings constitute evidence in favor of the autosomal recessive transmission of LPI.