Hyperlysinuria is an inborn error of metabolism, characterized by high amounts of the amino acid lysine in the urine causing a heavy load on the renal tubules. This condition arises due to the deficiency of the aminoadipic semialdehyse synthase enzyme that is involved in the metabolism of lysine. Apart from the high levels of lysine in the urine, usually, no other clinical signs can be seen. Thus, the condition is a benign one, with no adverse physical or mental effects.
Yadav et al. (1992) performed a quatitative HPLC analysis to detect any cases of aminoacidopathies among a group of 187 institutionalized mentally retarded patients (118 females) in Kuwait, during a 4-year period. One patient (0.23%) was detected to have hyperlysinuria.
In a retrospective analysis of IEMs diagnosed over a 12-year period (1998-2010) in a hospital in Lebanon, Karam et al. (2013) found one patient diagnosed with hyperlysinemia. The patient was diagnised at the age of 4-years.