[Identification of LINS1 gene variant in a patient with severe mental retardation]

To explore the genetic basis of a child with idiopathic mental retardation.

Clinical data and peripheral blood sample of the child were collected. Genomic DNA was extracted and subjected to copy number analysis using single nucleotide polymrophism array comparative genome hybridization (SNP-aCGH) and targeted capture and next generation sequencing (NGS).

No microdeletion/microduplication were detected by SNP-aCGH. NGS has detected homozygous c.722delA (p.Asp241fs) variant of the LISN1 gene, which is known to underlie autosomal recessive mental retardation-27 (MRT 27). Both parents are carriers of the variant, conforming to the autosomal recessive inheritance.

A novel pathogenic variant of the LINS1 gene has been identified, which probably underlies the MRT 27 in the patient.