Objective: To explore the genetic basis of a child with idiopathic mental retardation.
Methods: 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).
Results: 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.
Conclusion: A novel pathogenic variant of the LINS1 gene has been identified, which probably underlies the MRT 27 in the patient.