Rare missense variant inMSH4associated with primary gonadal failure in both 46, XX and 46, XY individuals

Abstract

STUDY QUESTION Can whole-exome sequencing (WES) reveal a shared pathogenic variant responsible for primary gonadal failure in both male and female patients from a consanguineous family? SUMMARY ANSWER Patients with primary ovarian insufficiency (POI) and non-obstructive azoospermia (NOA) were homozygous for the rare missense variant p. S754L located in the highly conserved MSH4 MutS signature motif of the ATPase domain. An oligozoospermic patient was heterozygous for the variant. WHAT IS KNOWN ALREADY MSH4 is a meiosis-specific protein expressed at a certain level in the testes and ovaries. Along with its heterodimer partner MSH5, it is responsible for double-strand Holliday junction recognition and stabilization, to ensure accurate chromosome segregation during meiosis. Knockout male and female mice for Msh4 and Msh5 are reportedly infertile due to meiotic arrest. In humans, MSH4 is associated with male and female gonadal failure, with distinct variations in the MutS domain V. STUDY DESIGN, SIZE, DURATION This was a retrospective genetics study of a consanguineous family with multiple cases of gonadal failure in both genders. The subject family was recruited in Iran, in 2018. PARTICIPANTS/MATERIALS, SETTING, METHODS The proband who is affected by POI, an NOA brother, a fertile sister and their parents were subjected to WES. The discovered variant was validated in these individuals, and the rest of the family was also genotyped by Sanger sequencing. The variant was not detected in 800 healthy Iranian individuals from the Iranome database nor in 30 sporadic NOA and 30 sporadic POI patients. Suggested effect in aberrant splicing was studied by RT-PCR. Moreover, protein homology modeling was used to further investigate the amino acid substitution in silico. MAIN RESULTS AND THE ROLE OF CHANCE The discovered variant is very rare and has never been reported in the homozygous state. It occurs in the ATPase domain at Serine 754, the first residue within the highly conserved MutS signature motif, substituting it with a Leucine. All variant effect prediction tools indicated this variant as deleterious. Since the substitution occurs immediately before the Walker B motif at position 755, further investigations based on protein homology were conducted. Considering the modeling results, the nature of the substituted amino acid residue and the distances between p. S754L variation and the residues of the Walker B motif suggested the possibility of conformational changes affecting the ATPase activity of the protein. LARGE SCALE DATA We have submitted dbSNP entry rs377712900 to ClinVar under SCV001169709, SCV001169708 and SCV001142647 for oligozoospermia, NOA and POI, respectively. LIMITATIONS, REASONS FOR CAUTION Studies in model organisms can shed more light on the role of this variant as our results were obtained by variant effect prediction tools and protein homology modeling. WIDER IMPLICATIONS OF THE FINDINGS Identification of variants in meiotic genes should improve genetic counseling for both male and female infertility. Also, as two of our NOA patients underwent testicular sperm extraction (TESE) with no success, ruling out the existence of pathogenic variants in meiotic genes in such patients prior to TESE could prove useful. STUDY FUNDING/COMPETING INTEREST(S) This study was financially supported by Royan Institute in Tehran, Iran, and Institut Pasteur in Paris, France. The authors declare no competing interests. TRIAL REGISTRATION NUMBER N/A

Non-invasive biomarkers for sperm retrieval in non-obstructive patients: a comprehensive review

“…Among the genes mutated in NOA reported by Kherraf et al. ( 14 ), and others ( 41 ), several (e.g. C14orf 39, HFM1 , MCM8 , MEIOB , MSH4 , DMC142 , STAG3, KASH5 ) are also associated with female infertility, underscoring common mechanisms in male and female meiosis.…”

Identification of compound heterozygous variants in MSH4 as a novel genetic cause of diminished ovarian reserve

“… c.2222_2225del p.Lys741Argfs*2 frameshift male/female NOA, POI 1,256,044 Li P et al, 2022 [ 18 ]. c.2261 C > T p.Ser754Leu missense male/female NOA,POI 869,115 Krausz et al, 2020 [ 21 ]; Akbari A et al, 2021 [ 20 ]. c.2355 + 1G > A —— splice site female POI 1,693,499 Carlosama C et al, 2017 [ 17 ].…”

Novel bi-allelic MSH4 variants causes meiotic arrest and non-obstructive azoospermia

“…The loss of Msh4 or Msh5 in mice resulted in defects of prophase I progression, with almost complete failure of homologous synapsis [ 9 – 11 ]. To date, WES of pedigree studies reported only two types of homozygous mutation in MSH4 (NM_002440.4: c.2261C > T and c.1552C > T) were associated with NOA [ 12 , 13 ]. MutS heterodimers are characterized by five distinct MutS domains (I-V), and each domain is responsible for a specific function.…”

“…It has been demonstrated that loss of Msh4 or Msh5 results in defects of prophase I progression in mice, with almost complete failure of homologous synapsis, and cell death prior to pachynema [ 9 – 11 ]. Also, up to now, whole-exome sequencing (WES) of pedigree studies reported that only two types of homozygous mutation in MSH4 (NM_002440.4: c.2261C > T and c.1552C > T) were associated with NOA [ 12 , 13 ]. Thus, many other types of mutation in MSH4 which were associated with NOA remain to be elucidated.…”