An increased concentration of lysine in the urine.

An increased level of a dibasic amino acid in the urine. Dibasic amino acids are usually refered to simply as basic aminoacids because they contain basic side chains at neutral pH. These are arginine (Arg), lysine (Lys), and histidine (His).

A deficiency or slowing down of growth pre- and postnatally.

Impaired ability to absorb one or more nutrients from the intestine.

Complete absence of wakefulness and content of conscience, which manifests itself as a lack of response to any kind of external stimuli.

A state of disinterestedness, listlessness, and indifference, resulting in difficulty performing simple tasks or concentrating.

Subnormal intellectual functioning which originates during the developmental period. Intellectual disability, previously referred to as mental retardation, has been defined as an IQ score below 70.

An increased concentration of ammonia in the blood.

Hyperlysinemia type I is an autosomal recessive metabolic condition with variable clinical features. Some patients who present in infancy with nonspecific seizures, hypotonia, or mildly delayed psychomotor development have been found to have increased serum lysine and pipecolic acid on laboratory analysis. However, about 50% of probands are reported to be asymptomatic, and hyperlysinemia is generally considered to be a benign metabolic variant (summary by Tondo et al., 2013; Houten et al., 2013). The AASS gene encodes a bifunctional enzyme: lysine alpha-ketoglutarate reductase and saccharopine dehydrogenase. In hyperlysinemia type I, both enzymatic functions of AASS are defective; in hyperlysinemia type II, also known as saccharopinuria (268700), some of the first enzymatic function is retained (Cox, 1985; Cox et al., 1986).