Multiple morphological abnormalities of sperm flagella (MMAF) is a severe form of asthenoteratozoospermia, characterized by morphological abnormalities and reduced motility of sperm, causing male infertility. Although approximately 60% of MMAF cases can be explained genetically, the etiology of the remaining cases is unclear. Here, we identified two novel compound heterozygous variants in the gene, dynein axonemal heavy chain 10 (DNAH10), in three patients from two unrelated Pakistani families using whole-exome sequencing (WES), including one compound heterozygous mutation (DNAH10: c.9409C>A [p.P3137T]; c.12946G>C [p.D4316H]) in family 1 and another compound heterozygous mutation (DNAH10: c.8849G>A [p.G2950D]; c.11509C>T [p.R3687W]) in family 2. All the identified variants are absent or rare in public genome databases and are predicted to have deleterious effects according to multiple bioinformatic tools. Sanger sequencing revealed that these variants follow an autosomal recessive mode of inheritance. Hematoxylin and eosin (H&E) staining revealed MMAF, including sperm head abnormalities, in the patients. In addition, immunofluorescence staining revealed loss of DNAH10 protein signals along sperm flagella. These findings broaden the spectrum of DNAH10 variants and expand understanding of the genetic basis of male infertility associated with the MMAF phenotype.

Keywords: asthenoteratozoospermia; DNAH10; male infertility; multiple morphological abnormalities of sperm flagella

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