Clinical characterization and further confirmation of the autosomal recessive SLC12A2 disease

J Hum Genet. 2021 Jul;66(7):689-695. doi: 10.1038/s10038-021-00904-2. Epub 2021 Jan 27.

Abstract

Heterozygous pathogenic variants in SLC12A2 are reported in patients with nonsyndromic hearing loss. Recently, homozygous loss-of-function variants have been reported in two patients with syndromic intellectual disability, with or without hearing loss. However, the clinical and molecular spectrum of SLC12A2 disease has yet to be characterized and confirmed. Using whole-exome sequencing, we detected a homozygous splicing variant in four patients from two independent families with severe developmental delay, microcephaly, respiratory abnormalities, and subtle dysmorphic features, with or without congenital hearing loss. We also reviewed the reported cases with pathogenic variants associated with autosomal dominant and recessive forms of the SLC12A2 disease. About 50% of the cases have syndromic and nonsyndromic congenital hearing loss. All patients harboring the recessive forms of the disease presented with severe global developmental delay. Interestingly, all reported variants are located in the c-terminal domain, suggesting a critical role of this domain for the proper function of the encoded co-transporter protein. In conclusion, our study provides an additional confirmation of the autosomal recessive SLC12A2 disease.

MeSH terms

  • Brain / diagnostic imaging
  • Brain / pathology
  • Child
  • Child, Preschool
  • Deafness / complications
  • Deafness / diagnostic imaging
  • Deafness / genetics*
  • Deafness / pathology
  • Exome / genetics
  • Exome Sequencing
  • Female
  • Genes, Recessive / genetics
  • Genetic Predisposition to Disease*
  • Homozygote
  • Humans
  • Infant
  • Intellectual Disability / complications
  • Intellectual Disability / diagnostic imaging
  • Intellectual Disability / genetics*
  • Intellectual Disability / pathology
  • Male
  • Mutation / genetics
  • Pedigree
  • Phenotype
  • RNA Splicing / genetics
  • Solute Carrier Family 12, Member 2 / deficiency
  • Solute Carrier Family 12, Member 2 / genetics*

Substances

  • SLC12A2 protein, human
  • Solute Carrier Family 12, Member 2

Supplementary concepts

  • Nonsyndromic Deafness