Author(s): Houten SM, Te Brinke H, Denis S, Ruiter JP, Knegt AC,
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Abstract BACKGROUND: Hyperlysinemia is an autosomal recessive inborn error of L-lysine degradation. To date only one causal mutation in the AASS gene encoding α-aminoadipic semialdehyde synthase has been reported. We aimed to better define the genetic basis of hyperlysinemia. METHODS: We collected the clinical, biochemical and molecular data in a cohort of 8 hyperlysinemia patients with distinct neurological features. RESULTS: We found novel causal mutations in AASS in all affected individuals, including 4 missense mutations, 2 deletions and 1 duplication. In two patients originating from one family, the hyperlysinemia was caused by a contiguous gene deletion syndrome affecting AASS and PTPRZ1. CONCLUSIONS: Hyperlysinemia is caused by mutations in AASS. As hyperlysinemia is generally considered a benign metabolic variant, the more severe neurological disease course in two patients with a contiguous deletion syndrome may be explained by the additional loss of PTPRZ1. Our findings illustrate the importance of detailed biochemical and genetic studies in any hyperlysinemia patient.
This article was published in Orphanet J Rare Dis
and referenced in Journal of Analytical & Bioanalytical Techniques