Mutations in the histamine N-methyltransferase gene, HNMT, are associated with nonsyndromic autosomal recessive intellectual disability.
نویسندگان
چکیده
Histamine (HA) acts as a neurotransmitter in the brain, which participates in the regulation of many biological processes including inflammation, gastric acid secretion and neuromodulation. The enzyme histamine N-methyltransferase (HNMT) inactivates HA by transferring a methyl group from S-adenosyl-l-methionine to HA, and is the only well-known pathway for termination of neurotransmission actions of HA in mammalian central nervous system. We performed autozygosity mapping followed by targeted exome sequencing and identified two homozygous HNMT alterations, p.Gly60Asp and p.Leu208Pro, in patients affected with nonsyndromic autosomal recessive intellectual disability from two unrelated consanguineous families of Turkish and Kurdish ancestry, respectively. We verified the complete absence of a functional HNMT in patients using in vitro toxicology assay. Using mutant and wild-type DNA constructs as well as in silico protein modeling, we confirmed that p.Gly60Asp disrupts the enzymatic activity of the protein, and that p.Leu208Pro results in reduced protein stability, resulting in decreased HA inactivation. Our results highlight the importance of inclusion of HNMT for genetic testing of individuals presenting with intellectual disability.
منابع مشابه
A Missense Mutation in the HMNT Gene Responsible for Autosomal Recessive Intellectual Disability in an Iranian Family with Consanguineous Marriage
Background and Aims: One of the neurotransmitters in the brain is Histamine which acts as several biological mechanism regulators like inflammation, gastric acid secretion, and neuromodulation. Inactivation of Histamine occurs by histamine N-methyltransferase (HNMT) enzyme. The HNMT transfers a methyl group from S-adenosyl-L-methionine to Histamine and is the main process for the termination of...
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ورودعنوان ژورنال:
- Human molecular genetics
دوره 24 20 شماره
صفحات -
تاریخ انتشار 2015