Hartnup Disease

A SPECIFIC hyperaminoaciduria affecting certain neutral alpha-amino acids is believed to be the one constant finding in all homozygous patients who have the autosomal recessive hereditary condition called Hartnup disease.1 , 2 There are three groups of alpha-amino acids whose transport is not abnormal in Hartnup disease: a neutral group, including the two "imino acids," proline and hydroxyproline, and the amino acid, glycine; the diaminomonocarboxylic amino acids, lysine, orthinine and arginine (cystine, which is a diaminodicarboxylic amino acid, is also included in the group, for reasons still to be clarified, although its excretion in association with the "basic" amino acids is abnormal . . .