Molecular diagnosis in a cohort of 114 patients with rare skeletal dysplasias

Am J Med Genet C Semin Med Genet. 2021 Sep;187(3):396-408. doi: 10.1002/ajmg.c.31937. Epub 2021 Sep 16.

Abstract

Molecular diagnosis is important to provide accurate genetic counseling of skeletal dysplasias (SD). Although next-generation sequencing (NGS) techniques are currently the preferred methods for analyzing these conditions, some of the published results have not shown a detection rate as high as it would be expected. The present study aimed to assess the diagnostic yield of targeted NGS combined with Sanger sequencing (SS) for low-coverage exons of genes of interest and exome sequencing (ES) in a series of patients with rare SD and use two patients as an example of our strategy. This study used two different in-house panels. Of 93 variants found in 88/114 (77%) patients, 57 are novel. The pathogenic variants found in the following genes: B3GALT6, PCYT1A, INPPL1, LIFR, of four patients were only detected by SS. In conclusion, the high diagnostic yield reached in the present study can be attributed to both a good selection of patients and the utilization of the SS for the insufficiently covered regions. Additionally, the two case reports-a patient with acrodysostosis related to PRKAR1A and another with ciliopathy associated with KIAA0753, add new and relevant clinical information to the current knowledge.

Keywords: KIAA0753 gene; PRKAR1A gene; exome sequencing; skeletal ciliopathy; skeletal dysplasia; targeted NGS.

Publication types

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

MeSH terms

  • Choline-Phosphate Cytidylyltransferase
  • Dysostoses*
  • Exome Sequencing
  • Galactosyltransferases
  • Genetic Counseling
  • High-Throughput Nucleotide Sequencing
  • Humans
  • Osteochondrodysplasias*

Substances

  • B3GALT6 protein, human
  • Galactosyltransferases
  • Choline-Phosphate Cytidylyltransferase
  • PCYT1A protein, human