MYT1L gene mutation chimerism with autism as the predominant phenotype: a case report and literature review / 中华实用儿科临床杂志

ABSTRACT

The clinical phenotypes and genotypes of a child with autism spectrum disorder (ASD) concomitant with MYT1L gene mutation were analyzed retrospectively, who was admitted to the Department of Rehabilitation Medicine of Henan Children′s Hospital in April 2019.Whole genome sequencing and copy number variations detection were performed on the child and relevant articles about MYT1L mutation were subjected to a literature review.It was found that this child had a missense mutation of MYT1L gene (c.2186T>G, p.Met729Arg) in 15 exon and was in a state of chimera, with about 10% of the mutation rate.This mutation was not identified in the parents and brother of this patient.A total of 18 reports of MYT1L-related genetic abnormalities were retrieved, including 53 patients in total (including this case), including 22 patients with point mutations and 30 patients containing MYT1L gene region with 2p25.3 chromosomal microdeletions.The incidence of autism was 45.0% (18/40 cases), that of overweight/obesity was 70.2% (33/47 cases) and that of dysnoesia/hypoevolutism was 96.2%(51/53 cases). However, chimeras had relatively mild symptoms.It indicates that the mutation of MYT1L is an important risk factor of ASD, but chimeras have mild symptoms.The children with ASD who are obese or overweight should be alerted to the possible presence of MYT1L mutation, and genetic testing can be performed to confirm the diagnosis and the possibility of chimerism.The spectrum of genetic mutations in ASD was expanded in this study.