Abstract

MARQUES, Cristina Joana et al. Heritable Genomic Imprinting defects in infertile patients with Oligozoospermia and Azoospermia. Arq Med [online]. 2007, vol.21, n.2, pp.41-45. ISSN 2183-2447.

Introduction: We studied infertile patients with oligozoospermia and azoospermia to determine if these conditions of decreased sperm production are associated with defective genomic imprinting. Methods: We included 23 semen samples from men undergoing investigation of infertility as follows: 7 with normozoospermia (controls) and 16 with oligozoospermia (9 moderate; 7 severe); and 7 testicular biopsies, before intracytoplasmic sperm injection: 3 with conserved spermatogenesis (controls: 2 anejaculation, 1 secondary obstructive azoospermia) and 4 with hypospermatogenesis (HP). Sperm DNA was decondensed, purified and treated with sodium bisulfite. The differential methylated region (18 CpGs) of the H19 gene (paternally methylated) was amplified by PCR (Polymerase Chain Reaction), including the CTCF (parental-allele specific CCCTC-binding factor) binding site-6 that also controls the expression of IGF2 (Insulin-like Growth Factor 2) gene. PCR fragments were then cloned in plasmids and the methylation status of each cytosine was determined by automated sequencing. Results: We found a significant higher proportion of 1) global H19 hypomethylation in HP (p=0.001), 2) attainment of ≥3 CpGs in severe oligozoospermia and HP (pimprinting is defective in the male germ line of patients with severe oligozoospermia and hypospermatogenesis, being aggravated as the testicular injury worsens.

Keywords : azoospermia; oligozoospermia; genomic imprinting; H19; male infertility; spermatozoa.

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