Compound heterozygous splice site variants in the SCLT1 gene highlight an additional candidate locus for Senior-Løken syndrome

Sci Rep. 2018 Nov 13;8(1):16733. doi: 10.1038/s41598-018-35152-6.

Abstract

Senior Løken syndrome (SLS) is a heterogeneous disorder characterized by severe retinal degenerations and juvenile-onset nephronophthisis. Genetic variants in ten different genes have been reported as the causes of SLS. Clinical evaluation of a patient with SLS and her unaffected parents revealed that the patient had infantile-onset retinal dystrophy and juvenile-onset nephronophthisis. Other systemic abnormalities included hepatic dysfunction, megacystis, mild learning disability, autism, obesity, and hyperinsulinemia. Whole-exome sequencing identified compound heterozygous SCLT1 variants (c.1218 + 3insT and c.1631A > G) in the patient. The unaffected parents were heterozygous for each variant. Transcript analysis using reverse transcription PCR demonstrated that the c.1218 + 3insT variant leads to exon 14 skipping (p.V383_M406del), while the other variant (c.1631A > G) primarily leads to exon 17 skipping (p.D480EfsX11) as well as minor amounts of two transcripts (6 bps deletion in the last of exon 17 [p.V543_K544del] and exons 17 and 18 skipping [p.D480E, S481_K610del]). Immunohistochemical analysis demonstrated that the Sclt1 protein was localized to the distal appendage of the photoreceptor basal body, indicating a ciliary protein. In conclusion, we identified compound heterozygous splice site variants of SCLT1 in a patient with a new form of ciliopathies that exhibits clinical features of SLS.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Child
  • Ciliopathies / genetics*
  • Exons / genetics
  • Female
  • Genetic Loci / genetics*
  • Heterozygote*
  • Humans
  • Infant
  • Kidney / metabolism
  • Kidney Diseases, Cystic / genetics*
  • Leber Congenital Amaurosis / genetics*
  • Mice
  • Optic Atrophies, Hereditary / genetics*
  • Protein Transport
  • RNA Splice Sites / genetics*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Retina / metabolism
  • Sodium Channels / genetics*
  • Sodium Channels / metabolism

Substances

  • RNA Splice Sites
  • RNA, Messenger
  • SCLT1 protein, human
  • Sodium Channels

Supplementary concepts

  • Senior Loken Syndrome