MLPA and sequence analysis of DPY19L2 reveals point mutations causing globozoospermia

Area of Science:

• Genetics
• Reproductive Biology
• Male Infertility

Background:

• Globozoospermia, a rare infertility phenotype, involves round-headed spermatozoa lacking acrosomes.
• Previous studies identified homozygous DPY19L2 gene deletions as a primary cause.
• The DPY19L2 pseudogene complicates specific gene amplification and sequencing.

Purpose of the Study:

• To investigate if heterozygous deletions and point mutations in DPY19L2 contribute to globozoospermia.
• To develop methods for detecting DPY19L2 variants despite pseudogene interference.

Main Methods:

• A cohort of 34 globozoospermia patients was studied.
• Multiplex Ligation-dependent Probe Amplification (MLPA) was used to detect heterozygous deletions.
• Specific amplification and sequencing of DPY19L2 exons and boundaries were performed.
• In silico analysis evaluated mutation pathogenicity.

Main Results:

• 84% of analyzed patients (n=31) showed DPY19L2 molecular alterations.
• Two heterozygous deletions and three point mutations were identified.
• Homozygous DPY19L2 deletion was found in 23 patients (67.6%).
• Identified mutations included nonsense (p.Q342*) and missense (p.R290H, p.M358K) variants.

Conclusions:

• Genetic alterations in DPY19L2 are the primary cause of globozoospermia.
• Molecular diagnostics for DPY19L2 should not be limited to homozygous deletions.
• DPY19L2 mutations are found across ethnic backgrounds, not just North African populations.
• Further research is needed to assess treatment outcomes for mutated vs. undiagnosed patients.