Novel inactivating mutations of the DCAF17 gene in American and Turkish families cause male infertility and female subfertility in the mouse model

Genetic epidemiology of Woodhouse-Sakati Syndrome in the Greater Middle East region and beyond: a systematic review

BACKGROUND

Woodhouse-Sakati syndrome (WSS) is a rare, autosomal recessive genetic disorder with variable clinical manifestations mainly affecting the endocrine and nervous systems. The aim of this study was to systematically review the genetic basis of WSS and report the genetic variants and clinical phenotypes associated with the disease.

METHODS

PubMed, Science Direct, Scopus, and Web of Science databases were searched from the time of inception until June 2022. Broad search terms were used to capture the literature describing all genetic variants associated with WSS. The search keywords used are "Woodhouse Sakati" along with the term "mutation" OR "gene" OR "variant" OR "polymorphism".

RESULTS

Twenty-five eligible studies were included in this study. One hundred and eighty-five patients in 97 families from 12 different countries were diagnosed with WSS. In patients from the Greater Middle East (GME) region, consanguineous marriages were common (67%). Thirteen different DCAF17 variants were associated with WSS development (including 8 identified in the GME region). The most frequent variant was a frameshift deletion variant (c.436delC, p.Ala147Hisfs*9) unique to Arabs that was reported in 11 cases from Tunisia, Kuwait, Qatar, Bahrain, and Saudi Arabia. There were no clear genotype-phenotype correlations for the different variants.

CONCLUSIONS

This systematic review highlights the molecular basis and clinical manifestations of WSS globally, including the GME region, where the disease is prevalent due to consanguinity. Additional studies are now needed to understand the genotype-phenotype correlation for different DCAF17 variants and their impact on the phenotypic heterogeneity observed in WSS patients.

Whole exome sequencing and transcript analysis discover a novel pathogenic splice site mutation in DCAF17 gene underlying Woodhouse-Sakati syndrome

Woodhouse-Sakati syndrome (WSS) is an extremely rare multisystemic disorder with neuroendocrine dysfunctions. It is characterized by hypogonadism, alopecia, diabetes mellitus, intellectual disability and progressive extrapyramidal syndrome along with radiological features of small pituitary gland, progressive frontoparietal white matter changes and abnormal accumulation of iron on globus pallidus. WSS is caused by mutations in DCAF17 gene that encodes for DDB1 and CUL4 associated factor 17. In this study, we report a 17-year-old boy with clinical and radiological features of WSS including mild global developmental delay, mild intellectual disability, sensorineural hearing loss, progressive extrapyramidal syndrome, alopecia, hypogonadotropic hypogonadism and dysmorphic features. Whole exome sequencing analysis revealed a novel potentially pathogenic splice donor site variant (c.458+1G>T) on the intron 4 of DCAF17 gene. Transcript analysis revealed splicing ablation resulting in aberrant splicing of exons 3 and 5 and skipping of exon 4 (c.322_458del). This results in a frameshift and is predicted to cause premature termination of protein synthesis resulting in a protein product of length 120 amino acids (p.[Gly108Ilefs*14]). Our study identified a novel pathogenic variant causing WSS in a patient and expands the spectrum of clinical and genetic characteristics of patients with WSS.

Causal and Candidate Gene Variants in a Large Cohort of Women With Primary Ovarian Insufficiency

CONTEXT

A genetic etiology likely accounts for the majority of unexplained primary ovarian insufficiency (POI).

OBJECTIVE

We hypothesized that heterozygous rare variants and variants in enhanced categories are associated with POI.

DESIGN

The study was an observational study.

SETTING

Subjects were recruited at academic institutions.

PATIENTS

Subjects from Boston (n = 98), the National Institutes of Health and Washington University (n = 98), Pittsburgh (n = 20), Italy (n = 43), and France (n = 32) were diagnosed with POI (amenorrhea with an elevated follicle-stimulating hormone level). Controls were recruited for health in old age or were from the 1000 Genomes Project (total n = 233).

INTERVENTION

We performed whole exome sequencing (WES), and data were analyzed using a rare variant scoring method and a Bayes factor-based framework for identifying genes harboring pathogenic variants. We performed functional studies on identified genes that were not previously implicated in POI in a D. melanogaster model.

MAIN OUTCOME

Genes with rare pathogenic variants and gene sets with increased burden of deleterious variants were identified.

RESULTS

Candidate heterozygous variants were identified in known genes and genes with functional evidence. Gene sets with increased burden of deleterious alleles included the categories transcription and translation, DNA damage and repair, meiosis and cell division. Variants were found in novel genes from the enhanced categories. Functional evidence supported 7 new risk genes for POI (USP36, VCP, WDR33, PIWIL3, NPM2, LLGL1, and BOD1L1).

CONCLUSIONS

Candidate causative variants were identified through WES in women with POI. Aggregating clinical data and genetic risk with a categorical approach may expand the genetic architecture of heterozygous rare gene variants causing risk for POI.

Integrated analysis of prognostic immune-related genes in the tumor microenvironment of ovarian cancer

Background

Ovarian cancer (OC) is a major cause of most gynecological cancer deaths, and the rates of incidence and mortality are increasing worldwide. However, factors in the tumor microenvironment (TME) related to OC and certain prognostic markers of OC are still unknown. We aimed to identify biomarkers connected to prognostic immunity based on clinical patients’ data from The Cancer Genome Atlas (TCGA).

Methods

We used the ESTIMATE algorithm to compute the immune and matrix scores of OC patients from TCGA. Next, differentially expressed genes (DEGs) according to the immune and matrix scores were obtained. Subsequently, genes (GZMB, C2orf37, CXCL13, and UBD) connected with prognostic immunity were determined. Moreover, functional enrichment analysis and the protein-protein interaction network showed that these genes were enriched in many biological processes related to immune function. The Tumor Immune Estimation Resource (TIMER) algorithm was also used to analyze the immune prognostic genes according to six immuno-infiltrating cells.

Results

According to high/low immune-scores and matrix-score groups, 682 common genes were identified, within 420 upregulated genes and 262 downregulated genes. Gene ontology (GO) analysis of biological process primarily enriched in T cell activation, regulation of lymphocyte activation and lymphocyte differentiation. OS analysis showed 45 genes (6.6%) were relevant in the final results. The Kaplan-Meier plotter database verified the top 10 genes related to prognosis, but only GZMB, C2orf37, CXCL13 and UBD were related to overall survival (OS).

Conclusions

GZMB, CXCL13, and UBD may influence prognosis via their effects on the infiltration of immune cells and therefore represent potential targets for OC immunotherapy.

Novel splicing-site mutation in DCAF17 gene causing Woodhouse-Sakati syndrome in a large consanguineous family

Background

Woodhouse‐Sakati syndrome is a rare autosomal recessive disease with endocrine and neuroectodermal aberrations with heterogeneous phenotypes and disease course. The most common phenotypes of the disease are progressive sensorineural hearing loss and alopecia, mild‐to‐moderate mental retardation and hypogonadism. The disease results from mutations in the DCAF17 gene.

Method

Here, we reported a large consanguineous pedigree with multiple affected individuals with Woodhouse‐Sakati syndrome phenotypes. Laboratory tests confirmed the endocrine perturbance in affected individuals. To find out the underlying genetic change, whole‐exome sequencing was carried out.

Result

Analysis of the exome data identified a splicing‐site deletion NM_025000.3:c.1423‐1_1425delGACA in DCAF17 gene. Sanger sequencing confirmed the co‐segregation of the variant with the disease phenotypes in the family.

Conclusion

The variant is predicted to cause aberrant splicing, i.e., exon skipping, resulting in the translation of a truncated functionless protein which results in appearance of typical phenotypic features and clinical laboratory findings of Woodhouse‐Sakati syndrome in affected members of the family.

Expanding on the phenotypic spectrum of Woodhouse-Sakati syndrome due to founder pathogenic variant in DCAF17: Report of 58 additional patients from Qatar and literature review

Woodhouse-Sakati syndrome (WSS) is a rare autosomal recessive neuroendocrine and ectodermal disorder caused by variants in the DCAF17 gene. In Qatar, the c.436delC variant has been reported as a possible founder pathogenic variant with striking phenotypic heterogeneity. In this retrospective study, we report on the clinical and molecular characteristics of additional 58 additional Qatari patients with WSS and compare them to international counterparts' findings. A total of 58 patients with WSS from 32 consanguineous families were identified. Ectodermal and endocrine (primary hypogonadism) manifestations were the most common presentations (100%), followed by diabetes mellitus (46%) and hypothyroidism (36%). Neurological manifestations were overlapping among patients with intellectual disability (ID) being the most common (75%), followed by sensorineural hearing loss (43%) and both ID and aggressive behavior (10%). Distinctive facial features were noted in all patients and extrapyramidal manifestations were uncommon (8.6%). This study is the largest to date on Qatari patients with WSS and highlights the high incidence and clinical heterogeneity of WSS in Qatar due to a founder variant c.436delC in the DCAF17 gene. Early suspicion of WSS among Qatari patients with hypogonadism and ID, even in the absence of other manifestations, would shorten the diagnostic odyssey, guide early and appropriate management, and avoid potential complications.

Comparison of single euploid blastocyst transfer cycle outcome derived from embryos with normal or abnormal cleavage patterns

RESEARCH QUESTION

To assess incidence of abnormal cleavage among biopsied blastocysts; to compare euploidy rates of the blastocysts with abnormal and normal cleavage; and to compare single euploid blastocyst transfer (SEBT) outcome derived from embryos with normal or abnormal cleavage.

DESIGN

Retrospective analysis of prospectively collected data in a private IVF clinic. Consecutive 554 patients (749 cycles) undergoing preimplantation genetic testing for aneuploidy (n = 497; 671 cycles) or monogenic diseases (n = 57; 78 cycles) were included. All assessments for abnormal cleavage were carried out retrospectively; presence of abnormal cleavage was not a factor in deciding which euploid embryo to transfer. A total of 1015 blastocysts were biopsied and 295 SEBT procedures were carried out. Main outcome measure was live birth rate (LBR).

RESULTS

Incidence of reverse cleavage, direct cleavage, and reverse plus direct cleavage, were 7.7%, 6.4% and 2.3%, respectively. Of the 1015 biopsied blastocysts, 35.0% were euploid. Blastocysts with abnormal cleavage, in total, had a significantly higher euploidy rate compared with blastocysts with normal cleavage (44.6% [74/166] versus 33.1% [281/849]; P = 0.017). The LBR after SEBT with normal, reverse and direct cleavage, and direct cleavage plus reverse cleavage, was 133/238 (55.9%), 6/26 (23.1%), 8/24 (33.3%) and 0/3 (0.0%) (P < 0.001). Generalized estimating equation analysis showed that the presence of abnormal cleavage pattern was the only independent predictor of LBR (OR 0.316; 95% CI 0.115 to 0.867; P = 0.013).

CONCLUSIONS

Blastocysts with direct or reverse cleavage should be biopsied in preimplantation genetic testing cycles if they are morphologically eligible. Euploid blastocysts with abnormal cleavage, however, have approximately half the LBR of those euploid blastocyst with normal cleavage, hence, blastocysts with abnormal cleavage should have lower priority for transfer.

Mitochondrial Dysfunction, Oxidative Stress and Neuroinflammation in Neurodegeneration with Brain Iron Accumulation (NBIA)

The syndromes of neurodegeneration with brain iron accumulation (NBIA) encompass a group of invalidating and progressive rare diseases that share the abnormal accumulation of iron in the basal ganglia. The onset of NBIA disorders ranges from infancy to adulthood. Main clinical signs are related to extrapyramidal features (dystonia, parkinsonism and choreoathetosis), and neuropsychiatric abnormalities. Ten NBIA forms are widely accepted to be caused by mutations in the genes PANK2, PLA2G6, WDR45, C19ORF12, FA2H, ATP13A2, COASY, FTL1, CP, and DCAF17. Nonetheless, many patients remain without a conclusive genetic diagnosis, which shows that there must be additional as yet undiscovered NBIA genes. In line with this, isolated cases of known monogenic disorders, and also, new genetic diseases, which present with abnormal brain iron phenotypes compatible with NBIA, have been described. Several pathways are involved in NBIA syndromes: iron and lipid metabolism, mitochondrial dynamics, and autophagy. However, many neurodegenerative conditions share features such as mitochondrial dysfunction and oxidative stress, given the bioenergetics requirements of neurons. This review aims to describe the existing link between the classical ten NBIA forms by examining their connection with mitochondrial impairment as well as oxidative stress and neuroinflammation.

Oocyte competence is maintained by m6A methyltransferase KIAA1429-mediated RNA metabolism during mouse follicular development

KIAA1429 (also known as vir-like m⁶A methyltransferase-associated protein (VIRMA)), a newly identified component of the RNA m⁶A methyltransferase complex, plays critical roles in guiding region-selective m⁶A deposition. However, in mammals, whether KIAA1429 mediates RNA m⁶A regulatory pathway functions in vivo remains unknown. Here, we show that the Kiaa1429-specific deficiency in oocytes resulted in female infertility with defective follicular development and fully grown germinal vesicle (GV) oocytes failing to undergo germinal vesicle breakdown (GVBD) and consequently losing the ability to resume meiosis. The oocyte growth is accompanied by the accumulation of abundant RNAs and posttranscriptional regulation. We found that the loss of Kiaa1429 could also lead to abnormal RNA metabolism in GV oocytes. RNA-seq profiling revealed that Kiaa1429 deletion altered the expression pattern of the oocyte-derived factors essential for follicular development. In addition, our data show that the conditional depletion of Kiaa1429 decreased the m⁶A levels in oocytes and mainly affected the alternative splicing of genes associated with oogenesis. In summary, the m⁶A methyltransferase KIAA1429-mediated RNA metabolism plays critical roles in folliculogenesis and the maintenance of oocyte competence.

A novel DCAF17 homozygous mutation in a girl with Woodhouse-Sakati syndrome and review of the current literature

Background Woodhouse-Sakati syndrome (WSS) (OMIM#241080) is an extremely rare multisystemic disease. Alopecia, hypogonadism, loss of hearing, hypothyroidism, diabetes mellitus (DM) and neurological disorders are the components of this syndrome. The syndrome is caused by homozygous or compound heterozygous mutations in DCAF17, and has recently been implicated in the development of both male and female gonads, thus resulting in hypogonadism. Case report A 16-year-old girl with consanguineous parents was admitted to our hospital with absence of breast development and amenorrhea. Hypogonadism was detected, in the form of hypergonadotropic hypogonadism. Whole-exome sequencing was used to identify the genetic etiology underlying the hypogonadism. A novel homozygous variant c.1091 + 1G > A was detected in DCAF17. Both parents were sequenced and identified as heterozygous for the same mutation. Conclusions We report a novel mutation detected in the DCAF17 gene and discuss the clinical findings in patients with previously reported mutations. Various manifestations of WSS, such as alopecia, endocrinological and neurological disorders, do not emerge until later in life, and therefore this situation can be challenging to diagnose particularly in pediatric cases, as in the present report. Careful attention should be paid to these additional findings, which may lead to early diagnosis and reduced genetic analysis costs, in patients with hypogonadism. In addition, there was no obvious genetic-phenotype correlation in reported cases.

Genetics of human female infertility†

About 10% of women of reproductive age are unable to conceive or carry a pregnancy to term. Female factors alone account for at least 35% of all infertility cases and comprise a wide range of causes affecting ovarian development, maturation of oocytes, and fertilization competence, as well as the potential of a fertilized egg for preimplantation development, implantation, and fetal growth. Genetic abnormalities leading to infertility in females comprise large chromosome abnormalities, submicroscopic chromosome deletion and duplications, and DNA sequence variations in the genes that control numerous biological processes implicated in oogenesis, maintenance of ovarian reserve, hormonal signaling, and anatomical and functional development of female reproductive organs. Despite the great number of genes implicated in reproductive physiology by the study of animal models, only a subset of these genes is associated with human infertility. In this review, we mainly focus on genetic alterations identified in humans and summarize recent knowledge on the molecular pathways of oocyte development and maturation, the crucial role of maternal-effect factors during embryogenesis, and genetic conditions associated with ovarian dysgenesis, primary ovarian insufficiency, early embryonic lethality, and infertility.

Neurodegeneration with Brain Iron Accumulation Disorders: Valuable Models Aimed at Understanding the Pathogenesis of Iron Deposition

Neurodegeneration with brain iron accumulation (NBIA) is a set of neurodegenerative disorders, which includes very rare monogenetic diseases. They are heterogeneous in regard to the onset and the clinical symptoms, while the have in common a specific brain iron deposition in the region of the basal ganglia that can be visualized by radiological and histopathological examinations. Nowadays, 15 genes have been identified as causative for NBIA, of which only two code for iron-proteins, while all the other causative genes codify for proteins not involved in iron management. Thus, how iron participates to the pathogenetic mechanism of most NBIA remains unclear, essentially for the lack of experimental models that fully recapitulate the human phenotype. In this review we reported the recent data on new models of these disorders aimed at highlight the still scarce knowledge of the pathogenesis of iron deposition.