An unusual familial Xp22.12 microduplication including EIF1AX: A novel candidate dosage-sensitive gene for premature ovarian insufficiency.

We report on the results of array-CGH and Whole exome sequencing (WES) studies carried out in a Tunisian family with 46,XX premature ovarian insufficiency (POI). This study has led to the identification of a familial Xp22.12 tandem duplication with a size of 559.4 kb, encompassing only three OMIM genes (RPS6KA3, SH3KBP1and EIF1AX), and a new heterozygous variant in SPIDR gene: NM_001080394.3:c.1845_1853delTATAATTGA (p.Ile616_Asp618del) segregating with POI. Increased mRNA expression levels were detected for SH3KBP1 and EIF1AX, while a normal transcript level for RPS6KA3 was detected in the three affected family members, explaining the absence of intellectual disability (ID). To the best of our knowledge, this is the first duplication involving the Xp22.12 region, reported in a family without ID, but rather with secondary amenorrhea (SA) and female infertility. As EIF1AX is a regulatory gene escaping X-inactivation, which has an extreme dosage sensitivity and highly expressed in the ovary, we suggest that this gene might be a candidate gene for ovarian function. Homozygous nonsense pathogenic variants of SPIDR gene have been reported in familial cases in POI. It has been suggested that chromosomal instability associated with SPIDR molecular defects supports the role of SPIDR protein in double-stranded DNA damage repair in vivo in humans and its causal role in POI. In this family, the variant (p.Ile616_Asp618del), present in a heterozygous state, is located in the domain that interacts with BLM and might disrupt the BLM binding ability of SPIDR protein. These findings strengthen the hypothesis that the additional effect of this variant could lead to POI in this family. Although the work represents the first evidence that EIF1AX duplication might be responsible for POI through its over-expression, further functional studies are needed to clarify and prove EIF1AX involvement in POI phenotype.

Relationship between nuclear DNA fragmentation, mitochondrial DNA damage and standard sperm parameters in spermatozoa of infertile patients with leukocytospermia.

The association of leukocytospermia with male fertility is still under debate. Our objective was to evaluate the association of leukocytospermia with sperm parameters, mitochondrial DNA (mtDNA) variations, and seminal concentration of several oxidative stress and inflammatory cytokines in Tunisian infertile men. The studied patients were divided into two groups: patients without leukocytospermia (Group 1) and patients with leukocytospermia (Group 2). DNA fragmentation significantly increased in group 2 (31.41 %) compared to group 1 (14.68 %) ; (p < 0.001). A total of 115 nucleotide substitutions in mitochondrial DNA were depicted, among which 113 were previously identified. The number of substitutions was more elevated in group 2. Leukocytospermic group had significantly higher MDA (nmole/mL) levels than patients without leukocytospermia (34±24.43 vs 18.94±15.96 ; p=0.001), GSH (µg/mL) levels were also higher compared to the control group (126.53±22.87 vs 79.4±19.38 ; p < 0.001), SOD (U/mg of protein) levels were higher but without reaching the statistical significance (89.74±74.85 vs 67.56±37.11 ; p = 0.25) ; whereas seminal CAT (µmole H2O2/min/mg of protein) levels were lower in this group (10.66±14.32 vs 27.35±25.28 ; p = 0.012). No statistically significant differences between the two groups of patients were found in the levels of inflammatory cytokines. However, IL-8 level was positively correlated with DNA fragmentation and negatively correlated with vitality. These findings confirm the association between leukocytospermia and sperm DNA damage.