Two ovarian candidate enhancers, identified by time series enhancer RNA analyses, harbor rare genetic variations identified in ovarian insufficiency.

The genetic regulation of ovarian development remains largely unclear. Indeed, in most cases of impaired ovarian development-such as 46,XX disorders of sex development (DSD) without SRY, and premature ovarian insufficiency (POI)-the genetic causes have not been identified, and the vast majority of disease-associated sequence variants could lie within non-coding regulatory sequences. In this study, we aimed to identify enhancers of five ovarian genes known to play key roles in early ovarian development, basing our analysis on the expression of enhancer derived transcripts (eRNAs), which are considered to characterize active enhancers. Temporal expression profile changes in mouse WT1-positive ovarian cells were obtained from cap analysis of gene expression at E13.5, E16.5 and P0. We compared the chronological expression profiles of ovarian-specific eRNA with expression profiles for each of the ovarian-specific genes, yielding two candidate sequences for enhancers of Wnt4 and Rspo1. Both sequences are conserved between mouse and human, and we confirmed their enhancer activities using transient expression assays in murine granulosa cells. Furthermore, by sequencing the region in patients with impaired ovarian development in 24 patients, such as POI, gonadal dysgenesis and 46,XX DSD, we identified rare single nucleotide variants in both sequences. Our results demonstrate that combined analysis of the temporal expression profiles of eRNA and mRNA of target genes presents a powerful tool for locating cis-element enhancers, and a means of identifying disease-associated sequence variants that lie within non-coding regulatory sequences, thus advancing an important unmet need in forward human genetics.

Biallelic FANCA variants detected in sisters with isolated premature ovarian insufficiency.

Premature ovarian insufficiency is a common form of female infertility affecting up to 4% of women and characterised by amenorrhea with elevated gonadotropin before the age of 40. Oocytes require controlled DNA breakage and repair for homologous recombination and the maintenance of oocyte integrity. Biallelic disruption of the DNA damage repair gene, Fanconi anemia complementation group A (FANCA), is a common cause of Fanconi anaemia, a syndrome characterised by bone marrow failure, cancer predisposition, physical anomalies and POI. There is ongoing dispute about the role of heterozygous FANCA variants in POI pathogenesis, with insufficient evidence supporting causation. Here, we have identified biallelic FANCA variants in French sisters presenting with POI, including a novel missense variant of uncertain significance and a likely pathogenic deletion that initially evaded detection. Functional studies indicated no discernible effect on DNA damage sensitivity in patient lymphoblasts. These novel FANCA variants add evidence that heterozygous loss of one allele is insufficient to cause DNA damage sensitivity and POI. We propose that intragenic deletions, that are relatively common in FANCA, may be missed without careful analysis, and could explain the presumed causation of heterozygous variants. Accurate variant curation is critical to optimise patient care and outcomes.

Deficiency of the mitochondrial ribosomal subunit, MRPL50, causes autosomal recessive syndromic premature ovarian insufficiency.

Premature ovarian insufficiency (POI) is a common cause of infertility in women, characterised by amenorrhea and elevated FSH under the age of 40 years. In some cases, POI is syndromic in association with other features such as sensorineural hearing loss in Perrault syndrome. POI is a heterogeneous disease with over 80 causative genes known so far; however, these explain only a minority of cases. Using whole-exome sequencing (WES), we identified a MRPL50 homozygous missense variant (c.335T > A; p.Val112Asp) shared by twin sisters presenting with POI, bilateral high-frequency sensorineural hearing loss, kidney and heart dysfunction. MRPL50 encodes a component of the large subunit of the mitochondrial ribosome. Using quantitative proteomics and western blot analysis on patient fibroblasts, we demonstrated a loss of MRPL50 protein and an associated destabilisation of the large subunit of the mitochondrial ribosome whilst the small subunit was preserved. The mitochondrial ribosome is responsible for the translation of subunits of the mitochondrial oxidative phosphorylation machinery, and we found patient fibroblasts have a mild but significant decrease in the abundance of mitochondrial complex I. These data support a biochemical phenotype associated with MRPL50 variants. We validated the association of MRPL50 with the clinical phenotype by knockdown/knockout of mRpL50 in Drosophila, which resulted abnormal ovarian development. In conclusion, we have shown that a MRPL50 missense variant destabilises the mitochondrial ribosome, leading to oxidative phosphorylation deficiency and syndromic POI, highlighting the importance of mitochondrial support in ovarian development and function.

Dominant TP63 missense variants lead to constitutive activation and premature ovarian insufficiency.

Premature ovarian insufficiency (POI) is a leading form of female infertility, characterised by menstrual disturbance and elevated follicle-stimulating hormone before age 40. It is highly heterogeneous with variants in over 80 genes potentially causative, but the majority of cases having no known cause. One gene implicated in POI pathology is TP63. TP63 encodes multiple p63 isoforms, one of which has been shown to have a role in the surveillance of genetic quality in oocytes. TP63 C-terminal truncation variants and N-terminal duplication have been described in association with POI, however, functional validation has been lacking. Here we identify three novel TP63 missense variants in women with nonsyndromic POI, including one in the N-terminal activation domain, one in the C-terminal inhibition domain, and one affecting a unique and poorly understood p63 isoform, TA*p63. Via blue-native page and luciferase reporter assays we demonstrate that two of these variants disrupt p63 dimerization, leading to constitutively active p63 tetramer that significantly increases the transcription of downstream targets. This is the first evidence that TP63 missense variants can cause isolated POI and provides mechanistic insight that TP63 variants cause POI due to constitutive p63 activation and accelerated oocyte loss in the absence of DNA damage.

Pseudodicentric Chromosome Originating from an X-Autosome Translocation in a Male Patient with Cryptozoospermia.

Genetic factors are responsible for 15% of male infertility conditions. Numerical and structural chromosomal anomalies are validated genetic factors leading to spermatogenic quantitative defects, with a frequency depending on the severity of the phenotype. Among the structural chromosomal rearrangements, dicentric chromosomes are generally observed in robertsonian translocations or in cases of Y chromosome isodicentrics. In X-autosome translocations, male carriers are generally infertile, regardless of the position of the breakpoint, due to interrupted spermatogenesis. We report an infertile man bearing an unusual balanced (X;22) translocation, with a centromeric X breakpoint generating a derivative pseudodicentric chromosome psu dic(22;X). Extensive cytogenetic analyses were necessary to determine the precise nature of the derivative chromosome. The likely cause of the reproductive phenotype of the patient is discussed based on meiotic chromosomal conformation.

Genomic testing in premature ovarian insufficiency: proceed with caution.

Genomic testing has the potential to transform outcomes for women with infertility conditions, such as premature ovarian insufficiency (POI), with growing calls for widespread diagnostic use. The current research literature, however, often uses poor variant curation leading to inflated diagnostic claims and fails to address the complexities of genomic testing for this condition. Without careful execution of the transition from research to the clinic, there is danger of inaccurate diagnoses and poor appreciation of broader implications of testing. This Forum outlines the benefits of genomic testing for POI and raises often overlooked concerns.

A recessive variant in TFAM causes mtDNA depletion associated with primary ovarian insufficiency, seizures, intellectual disability and hearing loss.

Mitochondrial disorders are collectively common, genetically heterogeneous disorders in both pediatric and adult populations. They are caused by molecular defects in oxidative phosphorylation, failure of essential bioenergetic supply to mitochondria, and apoptosis. Here, we present three affected individuals from a consanguineous family of Pakistani origin with variable seizures and intellectual disability. Both females display primary ovarian insufficiency (POI), while the male shows abnormal sex hormone levels. We performed whole exome sequencing and identified a recessive missense variant c.694C > T, p.Arg232Cys in TFAM that segregates with disease. TFAM (mitochondrial transcription factor A) is a component of the mitochondrial replisome machinery that maintains mtDNA transcription and replication. In primary dermal fibroblasts, we show depletion of mtDNA and significantly altered mitochondrial function and morphology. Moreover, we observed reduced nucleoid numbers with significant changes in nucleoid size or shape in fibroblasts from an affected individual compared to controls. We also investigated the effect of tfam impairment in zebrafish; homozygous tfam mutants carrying an in-frame c.141_149 deletion recapitulate the mtDNA depletion and ovarian dysgenesis phenotypes observed in affected humans. Together, our genetic and functional data confirm that TFAM plays a pivotal role in gonad development and expands the repertoire of mitochondrial disease phenotypes.

Genomic sequencing highlights the diverse molecular causes of Perrault syndrome: a peroxisomal disorder (PEX6), metabolic disorders (CLPP, GGPS1), and mtDNA maintenance/translation disorders (LARS2, TFAM).

Perrault syndrome is a rare heterogeneous condition characterised by sensorineural hearing loss and premature ovarian insufficiency. Additional neuromuscular pathology is observed in some patients. There are six genes in which variants are known to cause Perrault syndrome; however, these explain only a minority of cases. We investigated the genetic cause of Perrault syndrome in seven affected individuals from five different families, successfully identifying the cause in four patients. This included previously reported and novel causative variants in known Perrault syndrome genes, CLPP and LARS2, involved in mitochondrial proteolysis and mitochondrial translation, respectively. For the first time, we show that pathogenic variants in PEX6 can present clinically as Perrault syndrome. PEX6 encodes a peroxisomal biogenesis factor, and we demonstrate evidence of peroxisomal dysfunction in patient serum. This study consolidates the clinical overlap between Perrault syndrome and peroxisomal disorders, and highlights the need to consider ovarian function in individuals with atypical/mild peroxisomal disorders. The remaining patients had variants in candidate genes such as TFAM, involved in mtDNA transcription, replication, and packaging, and GGPS1 involved in mevalonate/coenzyme Q10 biosynthesis and whose enzymatic product is required for mouse folliculogenesis. This genomic study highlights the diverse molecular landscape of this poorly understood syndrome.

STAG3 homozygous missense variant causes primary ovarian insufficiency and male non-obstructive azoospermia.

Infertility, a global problem affecting up to 15% of couples, can have varied causes ranging from natural ageing to the pathological development or function of the reproductive organs. One form of female infertility is premature ovarian insufficiency (POI), affecting up to 1 in 100 women and characterised by amenorrhoea and elevated FSH before the age of 40. POI can have a genetic basis, with over 50 causative genes identified. Non-obstructive azoospermia (NOA), a form of male infertility characterised by the absence of sperm in semen, has an incidence of 1% and is similarly heterogeneous. The genetic basis of male and female infertility is poorly understood with the majority of cases having no known cause. Here, we study a case of familial infertility including a proband with POI and her brother with NOA. We performed whole-exome sequencing (WES) and identified a homozygous STAG3 missense variant that segregated with infertility. STAG3 encodes a component of the meiosis cohesin complex required for sister chromatid separation. We report the first pathogenic homozygous missense variant in STAG3 and the first STAG3 variant associated with both male and female infertility. We also demonstrate limitations of WES for the analysis of homologous DNA sequences, with this variant being ambiguous or missed by independent WES protocols and its homozygosity only being established via long-range nested PCR.

TP63-truncating variants cause isolated premature ovarian insufficiency.

Premature ovarian insufficiency involves amenorrhea and elevated follicle-stimulating hormone before age 40, and its genetic basis is poorly understood. Here, we study 13 premature ovarian insufficiency (POI) patients using whole-exome sequencing. We identify PREPL and TP63 causative variants, and variants in other potentially novel POI genes. PREPL deficiency is a known cause of syndromic POI, matching the patients' phenotype. A role for TP63 in ovarian biology has previously been proposed but variants have been described in multiorgan syndromes, and not isolated POI. One patient with isolated POI harbored a de novo nonsense TP63 variant in the terminal exon and an unrelated patient had a different nonsense variant in the same exon. These variants interfere with the repression domain while leaving the activation domain intact. We expand the phenotypic spectrum of TP63-related disorders, provide a new genotype:phenotype correlation for TP63 and identify a new genetic cause of isolated POI.

Pseudodicentric Chromosome Originating from Autosomes 9 and 21 in a Male Patient with Oligozoospermia.

Genetic factors are responsible for 15% of male infertility conditions. Numerical and structural chromosomal anomalies (related to the Y chromosome or to the autosomes) are validated genetic factors leading to spermatogenic quantitative defects with a frequency depending on the severity of the phenotype. The most frequent structural chromosomal rearrangements of autosomes are translocations and inversions, whereas dicentric chromosomes involving autosomes are rare. We report a man bearing a pseudodicentric chromosome (9;21) and presenting with oligozoospermia. Extensive cytogenetic analyses were necessary to determine the precise nature of the derivative chromosome and to discount the presence of interstitial telomeric sequences. Defects in spermatogenesis and abnormal segregation at meiosis for existing spermatozoa are proposed and are the likely cause of the reproductive phenotype of the patient.

22q11.2 rearrangements found in women with low ovarian reserve and premature ovarian insufficiency.

Ovarian reserve represents the number of available follicles/oocytes within ovaries and it can be assessed by follicle stimulating hormone levels, anti-Müllerian hormone levels, and/or antral follicle count determined by ultrasounds. A low ovarian reserve is defined by an abnormal ovarian reserve test. This condition can be considered premature if it occurs before the age of 40, leading to premature ovarian insufficiency. Despite the growing knowledge concerning the genetic basis of ovarian deficiency, the majority of cases remain without a genetic diagnosis. Although 22q11.2 deletions and duplications have been associated with genitourinary malformations, ovarian deficiency is not a commonly reported feature. We report here four patients bearing a 22q11.2 rearrangement, identified during the clinical assessment of their low ovarian reserve or premature ovarian insufficiency, and discuss the molecular basis of the ovarian defects.

ATAD3 gene cluster deletions cause cerebellar dysfunction associated with altered mitochondrial DNA and cholesterol metabolism.

Although mitochondrial disorders are clinically heterogeneous, they frequently involve the central nervous system and are among the most common neurogenetic disorders. Identifying the causal genes has benefited enormously from advances in high-throughput sequencing technologies; however, once the defect is known, researchers face the challenge of deciphering the underlying disease mechanism. Here we characterize large biallelic deletions in the region encoding the ATAD3C, ATAD3B and ATAD3A genes. Although high homology complicates genomic analysis of the ATAD3 defects, they can be identified by targeted analysis of standard single nucleotide polymorphism array and whole exome sequencing data. We report deletions that generate chimeric ATAD3B/ATAD3A fusion genes in individuals from four unrelated families with fatal congenital pontocerebellar hypoplasia, whereas a case with genomic rearrangements affecting the ATAD3C/ATAD3B genes on one allele and ATAD3B/ATAD3A genes on the other displays later-onset encephalopathy with cerebellar atrophy, ataxia and dystonia. Fibroblasts from affected individuals display mitochondrial DNA abnormalities, associated with multiple indicators of altered cholesterol metabolism. Moreover, drug-induced perturbations of cholesterol homeostasis cause mitochondrial DNA disorganization in control cells, while mitochondrial DNA aggregation in the genetic cholesterol trafficking disorder Niemann-Pick type C disease further corroborates the interdependence of mitochondrial DNA organization and cholesterol. These data demonstrate the integration of mitochondria in cellular cholesterol homeostasis, in which ATAD3 plays a critical role. The dual problem of perturbed cholesterol metabolism and mitochondrial dysfunction could be widespread in neurological and neurodegenerative diseases.

A founder mutation in PET100 causes isolated complex IV deficiency in Lebanese individuals with Leigh syndrome.

Leigh syndrome (LS) is a severe neurodegenerative disorder with characteristic bilateral lesions, typically in the brainstem and basal ganglia. It usually presents in infancy and is genetically heterogeneous, but most individuals with mitochondrial complex IV (or cytochrome c oxidase) deficiency have mutations in the biogenesis factor SURF1. We studied eight complex IV-deficient LS individuals from six families of Lebanese origin. They differed from individuals with SURF1 mutations in having seizures as a prominent feature. Complementation analysis suggested they had mutation(s) in the same gene but targeted massively parallel sequencing (MPS) of 1,034 genes encoding known mitochondrial proteins failed to identify a likely candidate. Linkage and haplotype analyses mapped the location of the gene to chromosome 19 and targeted MPS of the linkage region identified a homozygous c.3G>C (p.Met1?) mutation in C19orf79. Abolishing the initiation codon could potentially still allow initiation at a downstream methionine residue but we showed that this would not result in a functional protein. We confirmed that mutation of this gene was causative by lentiviral-mediated phenotypic correction. C19orf79 was recently renamed PET100 and predicted to encode a complex IV biogenesis factor. We showed that it is located in the mitochondrial inner membrane and forms a ∼300 kDa subcomplex with complex IV subunits. Previous proteomic analyses of mitochondria had overlooked PET100 because its small size was below the cutoff for annotating bona fide proteins. The mutation was estimated to have arisen at least 520 years ago, explaining how the families could have different religions and different geographic origins within Lebanon.

Mutations in the UQCC1-interacting protein, UQCC2, cause human complex III deficiency associated with perturbed cytochrome b protein expression.

Mitochondrial oxidative phosphorylation (OXPHOS) is responsible for generating the majority of cellular ATP. Complex III (ubiquinol-cytochrome c oxidoreductase) is the third of five OXPHOS complexes. Complex III assembly relies on the coordinated expression of the mitochondrial and nuclear genomes, with 10 subunits encoded by nuclear DNA and one by mitochondrial DNA (mtDNA). Complex III deficiency is a debilitating and often fatal disorder that can arise from mutations in complex III subunit genes or one of three known complex III assembly factors. The molecular cause for complex III deficiency in about half of cases, however, is unknown and there are likely many complex III assembly factors yet to be identified. Here, we used Massively Parallel Sequencing to identify a homozygous splicing mutation in the gene encoding Ubiquinol-Cytochrome c Reductase Complex Assembly Factor 2 (UQCC2) in a consanguineous Lebanese patient displaying complex III deficiency, severe intrauterine growth retardation, neonatal lactic acidosis and renal tubular dysfunction. We prove causality of the mutation via lentiviral correction studies in patient fibroblasts. Sequence-profile based orthology prediction shows UQCC2 is an ortholog of the Saccharomyces cerevisiae complex III assembly factor, Cbp6p, although its sequence has diverged substantially. Co-purification studies show that UQCC2 interacts with UQCC1, the predicted ortholog of the Cbp6p binding partner, Cbp3p. Fibroblasts from the patient with UQCC2 mutations have deficiency of UQCC1, while UQCC1-depleted cells have reduced levels of UQCC2 and complex III. We show that UQCC1 binds the newly synthesized mtDNA-encoded cytochrome b subunit of complex III and that UQCC2 patient fibroblasts have specific defects in the synthesis or stability of cytochrome b. This work reveals a new cause for complex III deficiency that can assist future patient diagnosis, and provides insight into human complex III assembly by establishing that UQCC1 and UQCC2 are complex III assembly factors participating in cytochrome b biogenesis.

Mutations in LYRM4, encoding iron-sulfur cluster biogenesis factor ISD11, cause deficiency of multiple respiratory chain complexes.

Iron-sulfur clusters (ISCs) are important prosthetic groups that define the functions of many proteins. Proteins with ISCs (called iron-sulfur or Fe-S proteins) are present in mitochondria, the cytosol, the endoplasmic reticulum and the nucleus. They participate in various biological pathways including oxidative phosphorylation (OXPHOS), the citric acid cycle, iron homeostasis, heme biosynthesis and DNA repair. Here, we report a homozygous mutation in LYRM4 in two patients with combined OXPHOS deficiency. LYRM4 encodes the ISD11 protein, which forms a complex with, and stabilizes, the sulfur donor NFS1. The homozygous mutation (c.203G>T, p.R68L) was identified via massively parallel sequencing of >1000 mitochondrial genes (MitoExome sequencing) in a patient with deficiency of complexes I, II and III in muscle and liver. These three complexes contain ISCs. Sanger sequencing identified the same mutation in his similarly affected cousin, who had a more severe phenotype and died while a neonate. Complex IV was also deficient in her skeletal muscle. Several other Fe-S proteins were also affected in both patients, including the aconitases and ferrochelatase. Mutant ISD11 only partially complemented for an ISD11 deletion in yeast. Our in vitro studies showed that the l-cysteine desulfurase activity of NFS1 was barely present when co-expressed with mutant ISD11. Our findings are consistent with a defect in the early step of ISC assembly affecting a broad variety of Fe-S proteins. The differences in biochemical and clinical features between the two patients may relate to limited availability of cysteine in the newborn period and suggest a potential approach to therapy.

Pharmacogenomic studies of fertility outcomes in pediatric cancer survivors - A systematic review.

For the same age, sex, and dosage, there can be significant variation in fertility outcomes in childhood cancer survivors. Genetics may explain this variation. This study aims to: (i) review the genetic contributions to infertility, (ii) search for pharmacogenomic studies looking at interactions of cancer treatment, genetic predisposition and fertility-related outcomes. Systematic searches in MEDLINE Ovid, Embase Classic+Embase, and PubMed were conducted using the following selection criteria: (i) pediatric, adolescent, and young adult cancer survivors, below 25 years old at the time of diagnosis, (ii) fertility outcome measures after cancer therapy, (iii) genetic considerations. Studies were excluded if they were (i) conducted in animal models, (ii) were not published in English, (iii) editorial letters, (iv) theses. Articles were screened in Covidence by at least two independent reviewers, followed by data extraction and a risk of bias assessment using the Quality in Prognostic Studies tool. Eight articles were reviewed with a total of 29 genes. Outcome measures included sperm concentration, azoospermia, AMH levels, assessment of premature menopause, ever being pregnant or siring a pregnancy. Three studies included replication cohorts, which attempted replication of SNP findings for NPY2R, BRSK1, FANCI, CYP2C19, CYP3A4, and CYP2B6. Six studies were rated with a high risk of bias. Differing methods may explain a lack of replication, and small cohorts may have contributed to few significant findings. Larger, prospective longitudinal studies with an unbiased genome-wide focus will be important to replicate significant results, which can be applied clinically.

A Human Homozygous HELQ Missense Variant Does Not Cause Premature Ovarian Insufficiency in a Mouse Model.

Disruption of meiosis and DNA repair genes is associated with female fertility disorders like premature ovarian insufficiency (POI). In this study, we identified a homozygous missense variant in the HELQ gene (c.596 A>C; p.Gln199Pro) through whole exome sequencing in a POI patient, a condition associated with disrupted ovarian function and female infertility. HELQ, an enzyme involved in DNA repair, plays a crucial role in repairing DNA cross-links and has been linked to germ cell maintenance, fertility, and tumour suppression in mice. To explore the potential association of the HELQ variant with POI, we used CRISPR/Cas9 to create a knock-in mouse model harbouring the equivalent of the human HELQ variant identified in the POI patient. Surprisingly, Helq knock-in mice showed no discernible phenotype, with fertility levels, histological features, and follicle development similar to wild-type mice. Despite the lack of observable effects in mice, the potential role of HELQ in human fertility, especially in the context of POI, should not be dismissed. Larger studies encompassing diverse ethnic populations and alternative functional approaches will be necessary to further examine the role of HELQ in POI. Our results underscore the potential uncertainties associated with genomic variants and the limitations of in vivo animal modelling.

Diverse genetic causes of amenorrhea in an ethnically homogeneous cohort and an evolving approach to diagnosis.

RESEARCH QUESTION: Premature ovarian insufficiency (POI) is characterised by amenorrhea associated with elevated follicle stimulating hormone (FSH) under the age of 40 years and affects 1-3.7% women. Genetic factors explain 20-30% of POI cases, but most causes remain unknown despite genomic advancements. DESIGN: We used whole exome sequencing (WES) in four Iranian families, validated variants via Sanger sequencing, and conducted the Acyl-cLIP assay to measure HHAT enzyme activity. RESULTS: Despite ethnic homogeneity, WES revealed diverse genetic causes, including a novel homozygous nonsense variant in SYCP2L, impacting synaptonemal complex (SC) assembly, in the first family. Interestingly, the second family had two independent causes for amenorrhea - the mother had POI due to a novel homozygous loss-of-function variant in FANCM (required for chromosomal stability) and her daughter had primary amenorrhea due to a novel homozygous GNRHR (required for gonadotropic signalling) frameshift variant. WES analysis also provided cytogenetic insights. WES revealed one individual was in fact 46, XY and had a novel homozygous missense variant of uncertain significance in HHAT, potentially responsible for complete sex reversal although functional assays did not support impaired HHAT activity. In the remaining individual, WES indicated likely mosaic Turners with the majority of X chromosome variants having an allelic balance of ∼85% or ∼15%. Microarray validated the individual had 90% 45,XO. CONCLUSIONS: This study demonstrates the diverse causes of amenorrhea in a small, isolated ethnic cohort highlighting how a genetic cause in one individual may not clarify familial cases. We propose that, in time, genomic sequencing may become a single universal test required for the diagnosis of infertility conditions such as POI.

LARS2 variants can present as premature ovarian insufficiency in the absence of overt hearing loss.

Premature ovarian insufficiency (POI) affects 1 in 100 women and is a leading cause of female infertility. There are over 80 genes in which variants can cause POI, with these explaining only a minority of cases. Whole exome sequencing (WES) can be a useful tool for POI patient management, allowing clinical care to be personalized to underlying cause. We performed WES to investigate two French sisters, whose only clinical complaint was POI. Surprisingly, they shared one known and one novel likely pathogenic variant in the Perrault syndrome gene, LARS2. Using amino-acylation studies, we established that the novel missense variant significantly impairs LARS2 function. Perrault syndrome is characterized by sensorineural hearing loss in addition to POI. This molecular diagnosis alerted the sisters to the significance of their difficulty in following conversation. Subsequent audiology assessment revealed a mild bilateral hearing loss. We describe the first cases presenting with perceived isolated POI and causative variants in a Perrault syndrome gene. Our study expands the phenotypic spectrum associated with LARS2 variants and highlights the clinical benefit of having a genetic diagnosis, with prediction of potential co-morbidity and prompt and appropriate medical care, in this case by an audiologist for early detection of hearing loss.