Next-generation sequencing for patients with non-obstructive azoospermia: implications for significant roles of monogenic/oligogenic mutations

Andrology. 2017 Jul;5(4):824-831. doi: 10.1111/andr.12378.

Abstract

Azoospermia affects up to 1% of adult men. Non-obstructive azoospermia is a multifactorial disorder whose molecular basis remains largely unknown. To date, mutations in several genes and multiple submicroscopic copy-number variations (CNVs) have been identified in patients with non-obstructive azoospermia. The aim of this study was to clarify the contribution of nucleotide substitutions in known causative genes and submicroscopic CNVs in the genome to the development of non-obstructive azoospermia. To this end, we conducted sequence analysis of 25 known disease-associated genes using next-generation sequencing and genome-wide copy-number analysis using array-based comparative genomic hybridization. We studied 40 Japanese patients with idiopathic non-obstructive azoospermia. Functional significance of molecular alterations was assessed by in silico analyses. As a result, we identified four putative pathogenic mutations, four rare polymorphisms possibly associated with disease risk, and four probable neutral variants in 10 patients. These sequence alterations included a heterozygous splice site mutation in SOHLH1 and a hemizygous missense substitution in TEX11, which have been reported as causes of non-obstructive azoospermia. Copy-number analysis detected five X chromosomal or autosomal CNVs of unknown clinical significance, in addition to one known pathogenic Y chromosomal microduplication. Five patients carried multiple molecular alterations. The results indicate that monogenic and oligogenic mutations, including those in SOHLH1 and TEX11, account for more than 10% of cases of idiopathic non-obstructive azoospermia. Furthermore, this study suggests possible contributions of substitutions in various genes as well as submicroscopic CNVs on the X chromosome and autosomes to non-obstructive azoospermia, which require further validation.

Keywords: copy-number variation; infertility; mutation; next-generation sequencer; oligogenic disorder.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Azoospermia / diagnosis
  • Azoospermia / genetics*
  • Azoospermia / physiopathology
  • Basic Helix-Loop-Helix Transcription Factors / genetics
  • Chromosomal Proteins, Non-Histone / genetics
  • Chromosomes, Human, X
  • Chromosomes, Human, Y
  • Comparative Genomic Hybridization*
  • DNA Copy Number Variations
  • DNA Mutational Analysis / methods*
  • Fertility / genetics*
  • Gene Dosage
  • Genetic Predisposition to Disease
  • Genome-Wide Association Study
  • High-Throughput Nucleotide Sequencing*
  • Humans
  • Japan
  • Male
  • Multifactorial Inheritance*
  • Mutation*
  • Phenotype
  • Polymorphism, Genetic*
  • Predictive Value of Tests

Substances

  • Basic Helix-Loop-Helix Transcription Factors
  • Chromosomal Proteins, Non-Histone
  • SOHLH1 protein, human
  • TEX11 protein, human

Supplementary concepts

  • Azoospermia, Nonobstructive