A biallelic loss of function variant in HORMAD1 within a large consanguineous Turkish family is associated with spermatogenic arrest.

STUDY QUESTION: Can the analysis of a large Turkish consanguineous family via whole exome sequencing (WES) identify novel causative genetic variation responsible for nonobstructive azoospermia (NOA) characterized by arrest at primary spermatocyte stage? SUMMARY ANSWER: WES analysis revealed a homozygous nonsense variant in HORMAD1 in three affected brothers of a Turkish family. WHAT IS KNOWN ALREADY: Studying patient cohorts in small or large consanguineous families using high-throughput sequencing allows the identification of genetic causes of different pathologies, including infertility. Over the last two decades, a number of genes involved in human male infertility have been discovered, but only 14 genes have been identified as being at least moderately linked to isolated NOA or oligozoospermia in men. STUDY DESIGN, SIZE, DURATION: The study included a Turkish family comprising three brothers with NOA. Two brothers had a normal karyotype, normal hormonal levels and no Yq microdeletion. The testicular histopathology analysis revealed the complete arrest of spermatogenesis at the primary spermatocyte stage. PARTICIPANTS/MATERIALS, SETTING, METHODS: We recruited a consanguineous Turkish family where parents were first-degree cousins and had seven children; three sons who had NOA, two sons who were fertile and two daughters for whom no information was available. Saliva samples from the index patient, his two affected brothers, parents and two nonaffected brothers (seven samples in total) were collected. Prior to WES, the index patient underwent targeted genetic testing using an infertility panel, which includes 133 infertility genes. No pathogenic variations were identified. WES was then performed on the DNA of the seven family members available. Bioinformatics analysis was performed using an in-house pipeline. Detected variants were scored and ranked, and copy number variants were called and annotated.The consequences of mutation on protein expression and localization were investigated by cell transfection followed by immunofluorescence or immunoblotting. MAIN RESULTS AND THE ROLE OF CHANCE: WES revealed a homozygous nonsense variant chr1:150675797G>A; HORMAD1 (NM_032132.5): c.1021C>T, p.Gln341* in exon 13, which was confirmed in all three affected brothers. HORMAD1 encodes the HORMA domain-containing protein 1. The parents as well as the two fertile brothers were carriers of this variant. This variant may lead to the production of a truncated protein lacking the nuclear localization signal; therefore, human cells were transfected with the wild-type and mutated form, in fusion with green fluorescent protein. Immunoblotting experiments confirmed the production of a truncated HORMAD1 protein, and immunofluorescence microscopy revealed that the mutated protein displayed cytoplasmic localization while the wild type protein located to the nucleus. Altogether, our findings validate HORMAD1 as an essential genetic factor in the meiotic process in human. LIMITATIONS, REASONS FOR CAUTION: According to one scoring system used to evaluate the clinical validity of male infertility genes, this study would classify HORMAD1 as displaying limited clinical evidence of being involved in male infertility. However, such a score is the maximum possible when only one family is analyzed and the addition of one patient showing a pathogenic or likely pathogenic variant would immediately change this classification to 'moderate'. Thus, this report should prompt other researchers to screen patients with NOA for this genetic variant. WIDER IMPLICATIONS OF THE FINDINGS: Identification of new genetic factors involved in the human meiosis process will contribute to an improvement of our knowledge at the basic level, which in turn will allow the management of better care for infertile patients. Since Hormad1-/- knock-out female mice are also infertile, HORMAD1 could also be involved in human female infertility. Our findings have direct implications for the genetic counseling of patients and their family members. STUDY FUNDING/COMPETING INTEREST(S): The study was funded by Fondation Maladies Rares (High Throughput Sequencing and Rare Diseases-2018, 'GenOmics of rare diseases'). The authors declare that they have no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.

Identification and structural characterization of a pathogenic ARSA missense variant in two consanguineous families from Jammu and Kashmir (India) with late infantile metachromatic leukodystrophy.

BACKGROUND: Metachromatic leukodystrophy (MLD) is a rare lysosomal storage disorder caused by a deficiency of Arylsulfatase A (ARSA) enzyme activity. Its clinical manifestations include progressive motor and cognitive decline. ARSA gene mutations are frequent in MLD. METHODS AND RESULTS: In the present study, whole exome sequencing (WES) was employed to decipher the genetic cause of motor and cognitive decline in proband's of two consanguineous families from J&K (India). Clinical investigations using radiological and biochemical analysis revealed MLD-like features. WES confirmed a pathogenic variant in the ARSA gene. Molecular simulation dynamics was applied for structural characterization of the variant. CONCLUSION: We report the identification of a pathogenic missense variant (c.1174 C > T; p.Arg390Trp) in the ARSA gene in two cases of late infantile MLD from consanguineous families in Jammu and Kashmir, India. Our study utilized genetic analysis and molecular dynamics simulations to identify and investigate the structural consequences of this mutation. The molecular dynamics simulations revealed significant alterations in the structural dynamics, residue interactions, and stability of the ARSA protein harbouring the p.Arg390Trp mutation. These findings provide valuable insights into the molecular mechanisms underlying the pathogenicity of this variant in MLD.

KIF1A novel frameshift variant p.(Ser887Profs*64) exhibits clinical heterogeneity in a Pakistani family with hereditary sensory and autonomic neuropathy type IIC.

Background: Hereditary sensory and autonomic neuropathies (HSANs) are rare heterogeneous group of neurological disorders caused by peripheral nerve deterioration. The HSANs sub-clinical classes have clinical and genetic overlap which often lead to misdiagnosis. In the present study a Pakistani family with five affected members suffering from severe neuropathy were genetically analyzed to identify the disease causative element in the family.Methods: Genome wide high-density single nucleotide polymorphism (SNP) microarray analysis was carried out followed by whole exome sequencing of the affected proband and another affected sibling. Shared homozygous regions in all severely affected members were identified through homozygosity mapping approach.Results: The largest homozygous region of 14.1 Mb shared by the five severely affected members of the family was identified on chromosome 2. Subsequent exome sequencing identified a novel single nucleotide deletion c.2658del; p.(Ser887Profs*64) in KIF1A. Segregation analysis revealed that this mutation was homozygous in all five affected individuals of the family with severe clinical manifestation, while members of the family that were heterozygous carriers shared abnormal skin features (scaly skin) only with the homozygous affected members.Conclusions: A novel frameshift mutation p.(Ser887Profs*64) in KIF1A is the potential cause of severe HSANIIC in a Pakistani family along with incomplete penetrance in mutation carriers. We demonstrate that using a combination of different techniques not only strengthens the gene finding approach but also helps in proper sub-clinical characterization along with identification of mutated alleles exhibiting incomplete penetrance leading to intrafamilial clinical variability in HSAN group of inherited diseases.

Giant axonal neuropathy with novel GAN pathogenic variant in a patient of consanguineous origin from Poonch Jammu and Kashmir-India.

Giant axonal neuropathy (GAN) is a severe and rare autosomal recessive neurodegenerative disorder of childhood affecting both the peripheral and central nervous systems (CNS). It is caused by mutations in the GAN (gigaxonin) gene linked to chromosome 16q24. Here, we present a 15-year-old male patient with GAN from a consanguineous family of Poonch, Jammu and Kashmir (J&K)-India. Whole-exome sequencing (WES) was employed to unravel the genetic cause of GAN in the proband. Pathogenic variant identified with WES was confirmed in other affected sibling using Sanger sequencing. Magnetic resonance imaging (MRI) and detailed clinical investigation was also carried out on proband. WES revealed a novel homozygous stopgain GAN mutation (NM_022041, c.C1028G, p.S343X) in the patient. MRI of brain displayed bilateral symmetrical confluent areas of deep white matter signal changes affecting periventricular regions (with sparing of subcortical U-fibers), posterior limbs of internal capsules, thalami, external capsules, and semioval centers. The patient was initially suspected to be a case of metachromatic leukodystrophy. However, WES analysis revealed a pathogenic variant in GAN gene as causative. No other pathogenic variant relevant to any other type of dystrophy was reported in WES. Our findings extend the geographical distribution of GAN to even a very remote region in India, extend the mutational and imaging spectrum of GAN and substantiate the need for introducing genetic testing and counselling in primary referral centers/district hospitals in India.

PDCD6IP, encoding a regulator of the ESCRT complex, is mutated in microcephaly.

Primary microcephaly (PM) is a highly heterogeneous neurodevelopmental disorder with many contributing risk genes and loci identified to date. We report a consanguineous family with PM, intellectual disability and short stature. Using whole exome sequencing, we identified a homozygous frameshift variant in programmed cell death 6 interacting protein (PDCD6IP, c.154_158dup; p.Val54Profs*18). This gene, PDCD6IP, plays an important role in the endosomal sorting complexes required for transport (ESCRT) pathway in the abscission stage of cytokinesis and apoptosis, and is required for normal brain development in mice. The clinical features observed in our patient were similar to the phenotypes observed in mouse and zebrafish models of PDCD6IP mutations in previous studies. This study provides evidence that clinical manifestations of PDCD6IP mutations as seen in our patients with PM and ID may be a novel cause for neurodevelopmental disorders.

A report of congenital adrenal hyperplasia due to 17α-hydroxylase deficiency in two 46,XX sisters.

Congenital adrenal hyperplasia (CAH) is a group of rare orphan disorders caused by mutations in seven different enzymes that impair cortisol biosynthesis. The 17α-hydroxylase deficiency (17OHD) is one of the less common forms of CAH, corresponding to approximately 1% of the cases, with an estimated annual incidence of 1 in 50,000 newborns. Cases description - two phenotypically female Ecuadorian sisters, both with primary amenorrhea, absence of secondary sexual characteristics, and osteoporosis. High blood pressure was present in the older sister. Hypergonadotropic hypogonadism profile was observed: decreased cortisol and dehydroepiandrosterone sulfate (DHEAS), increased adrenocorticotropic hormone (ACTH) and normal levels of 17-hydroxyprogesterone, extremely high deoxycorticosterone (DOC) levels, and a tomography showed bilateral adrenal hyperplasia in both sisters. Consanguinity was evident in their ancestors. Furthermore, in the exon 7, the variant c.1216T > C, p.Trp406Arg was detected in homozygosis in the CYP17A1 gene of both sisters. We report a homozygous missense mutation in the CYP17A1 gene causing 17OHD in two sisters from Loja, Ecuador. According to the authors, this is the first time such deficiency and mutation are described in two members of the same family in Ecuador.

Homozygous missense variant in the TTN gene causing autosomal recessive limb-girdle muscular dystrophy type 10.

BACKGROUND: Limb-girdle muscular dystrophies (LGMDs) are large group of heterogeneous genetic diseases, having a hallmark feature of muscle weakness. Pathogenic mutations in the gene encoding the giant skeletal muscle protein titin (TTN) are associated with several muscle disorders, including cardiomyopathy, recessive congenital myopathies and limb-girdle muscular dystrophy (LGMD) type10. The phenotypic spectrum of titinopathies is expanding, as next generation sequencing (NGS) technology makes screening of this large gene possible. AIM: This study aimed to identify the pathogenic variant in a consanguineous Pakistani family with autosomal recessive LGMD type 10. METHODS: DNA from peripheral blood samples were obtained, whole exome sequencing (WES) was performed and several molecular and bioinformatics analysis were conducted to identify the pathogenic variant. TTN coding and near coding regions were further amplified using PCR and sequenced via Sanger sequencing. RESULTS: Whole exome sequencing analysis revealed a novel homozygous missense variant (c.98807G > A; p.Arg32936His) in the TTN gene in the index patients. No heterozygous individuals in the family presented LGMD features. The variant p.Arg32936His leads to a substitution of the arginine amino acid at position 32,936 into histidine possibly causing LGMD type 10. CONCLUSION: We identified a homozygous missense variant in TTN, which likely explains LGMD type 10 in this family in line with similar previously reported data. Our study concludes that WES is a successful molecular diagnostic tool to identify pathogenic variants in large genes such as TTN in highly inbred population.

Biallelic mutations in PMFBP1 cause acephalic spermatozoa.

The majority of men with defects in spermatogenesis remain undiagnosed. Acephalic spermatozoa is one of the diseases causing primary infertility. However, the causes underlying over half of affected cases remain unclear. Here, we report by whole-exome sequencing the identification of homozygous and compound heterozygous truncating mutations in PMFBP1 of two unrelated individuals with acephalic spermatozoa. PMFBP1 was highly and specifically expressed in human and mouse testis. Furthermore, immunofluorescence staining in sperm from a normal control showed that PMFBP1 localizes to the head-flagella junction region, and the absence of PMFBP1 was confirmed in patients harboring PMFBP1 mutations. In addition, we generated Pmfbp1 knock-out (KO) mice, which we found recapitulate the acephalic sperm phenotype. Label-free quantitative proteomic analysis of testicular sperm from Pmfbp1 KO and control mice showed 124 and 35 proteins, respectively, increased or decreased in sperm from KO mice compared to that found in control mice. Gene ontology analysis indicates that the biological process of Golgi vesicle transport was the most highly enriched in differentially expressed proteins, indicating process defects related to Golgi complex function may disturb formation of the head-neck junction. Collectively, our data indicate that PMFBP1 is necessary for sperm morphology in both humans and mice, and that biallelic truncating mutations in PMFBP1 cause acephalic spermatozoa.

TSGA10 is a novel candidate gene associated with acephalic spermatozoa.

Acephalic spermatozoa is a rare teratozoospermia associated with male infertility. However, the pathogenesis of this disorder remains unclear. Here, we report a 27 years old infertile male from a consanguineous family, who presented with 99% headless sperm in his ejaculate. Electron microscopic and immunofluorescence analysis suggested breakage at the midpiece of the patient's sperm cells. Subsequent whole-exome sequencing analysis identified a homozygous deletion within TSGA10 (c.211delG; p.A71Hfs*12), which resulted in the production of truncated TSGA10 protein. TSGA10 is a testis-specific protein that localized to the midpiece in the spermatozoa of a normal control; however, immunostaining failed to detect TSGA10 protein in the patient's sperm. Western blot analysis also showed complete absence of TSGA10 protein in the patient. One cycle of in vitro fertilization-assisted reproduction was conducted, but pregnancy was not achieved after embryo transfer, possibly due to poor embryo quality. Therefore, we speculate that the presence of rare sequence variants within TSGA10 may be associated with acephalic spermatozoa in humans.

A Novel Homozygous SACS Mutation Identified by Whole-Exome Sequencing in a Consanguineous Family with Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay.

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a hereditary neurological disorder mostly manifested with a classical triad: progressive early-onset cerebellar ataxia, lower limb pyramidal signs, and peripheral neuropathy. We employed whole-exome sequencing and bioinformatics to identify the genetic cause in an ARSACS patient from a consanguineous family. Based on whole-exome sequences of the patient and her healthy parents, a novel homozygous deletion variant (NM_014363: c.9495_9508del; p.F3166Tfs*9) in the SACS gene was identified in the patient. This frameshift mutation is predicted to generate a truncated sacsin protein, which results in the loss of the C-terminal 1,406 amino acids. Our study provides a potential genetic diagnosis for the patient and expands the spectrum of SACS mutations.

A novel PAX1 null homozygous mutation in autosomal recessive otofaciocervical syndrome associated with severe combined immunodeficiency.

Otofaciocervical syndrome (OFCS) is a rare disorder characterized by facial anomalies, cup-shaped low-set ears, preauricular fistulas, hearing loss, branchial defects, skeletal anomalies, and mild intellectual disability. Autosomal dominant cases are caused by deletions or point mutations of EYA1. A single family with an autosomal recessive form of OFCS and a homozygous missense mutation in PAX1 gene has been described. We report whole exome sequencing of 4 members of a consanguineous family in which 2 children, showing features of OFCS, expired from severe combined immunodeficiency (SCID). To date, the co-occurrence of OFCS and SCID has never been reported. We found a nonsense homozygous mutation in PAX1 gene in the 2 affected children. In mice, Pax1 is required for the formation of specific skeletal structures as well as for the development of a fully functional thymus. The mouse model strongly supports the hypothesis that PAX1 depletion in our patients caused thymus aplasia responsible for SCID. This report provides evidence that bi-allelic null PAX1 mutations may lead to a multi-system autosomal recessive disorders, where SCID might represent the main feature.

Sclerosteosis caused by a novel nonsense mutation of SOST in a consanguineous family.

Sclerosteosis, characterized by the hyperostosis of cranial and tubular bones, is a rare autosomal recessive hereditary disorder caused by mutation of SOST gene. Four nonsense mutations of SOST have been identified worldwide. Here, we report two affected siblings who carried a novel nonsense mutation of SOST in a consanguineous family from China. The proband manifested typical symptoms of sclerosteosis, whereas the symptoms were absent in another affected sibling. Two nucleotide substitutions in exon 2 of SOST were identified, c.444_445TC>AA, resulting in a premature stop codon, p.Cys148→Stop. This truncated mutation loses 66 amino acid residues which contain 3 cysteine residues of the cysteine-knot motif, leading to loss of function of SOST. The symptoms of sclerosteosis may be clinically heterogeneous in some patients, even with the same mutation. Our results support the notion that founder effects from the ancestors contribute to the disease onset.

Further delineation of Wiedemann-Rautenstrauch syndrome linked with POLR3A.

Wiedemann-Rautenstrauch Syndrome (WRS; MIM 264090) is an extremely rare and highly heterogeneous syndrome that is inherited in a recessive fashion. The patients have hallmark features such as prenatal and postnatal growth retardation, short stature, a progeroid appearance, hypotonia, facial dysmorphology, hypomyelination leukodystrophy, and mental impairment. Biallelic disease-causing variants in the RNA polymerase III subunit A (POLR3A) have been associated with WRS. Here, we report the first identified cases of WRS syndrome with novel phenotypes in three consanguineous families (two Omani and one Saudi) characterized by biallelic variants in POLR3A. Using whole-exome sequencing, we identified one novel homozygous missense variant (NM_007055: c.2456C>T; p. Pro819Leu) in two Omani families and one novel homozygous variant (c.1895G>T; p Cys632Phe) in Saudi family that segregates with the disease in the POLR3A gene. In silico homology modeling of wild-type and mutated proteins revealed a substantial change in the structure and stability of both proteins, demonstrating a possible effect on function. By identifying the homozygous variants in the exon 14 and 18 of the POLR3A gene, our findings will contribute to a better understanding of the phenotype-genotype relationship and molecular etiology of WRS syndrome.

A novel homozygous TUB mutation associated with autosomal recessive retinitis pigmentosa in a consanguineous Chinese family.

BACKGROUND: Retinitis pigmentosa (RP) is the most common type of inherited retinopathy. At least 69 genes for RP have been identified. A significant proportion of RP, however, remains genetically unsolved. In this study, the genetic basis of a Chinese consanguineous family with presumed autosomal recessive retinitis pigmentosa (arRP) was investigated. METHODS: Overall ophthalmic examinations, including funduscopy, decimal best-corrected visual acuity, axial length and electroretinography (ERG) were performed for the family. Genomic DNA from peripheral blood of the proband was subjected to whole exome sequencing. In silico predictions, structural modelling, and minigene assays were conducted to evaluate the pathogenicity of the variant. RESULTS: A novel homozygous variant (NM_003320.4: c.1379A > G) in the TUB gene was identified as a candidate pathogenic variant in this parental consanguineous pedigree. This variant co-segregated with the disease in this pedigree and was absent in 118 ethnically matched healthy controls. It's an extremely rare variant that is neither deposited in population databases (1000 Genomes, ExAC, GnomAD, or Exome Variant Server) nor reported in the literature. Phylogenetic analysis indicated that the Asn residue at codon 460 of TUB is highly conserved across diverse species from tropicalis to humans. It was also completely conserved among the TUB, TULP1, TULP2, and TULP3 family proteins. Multiple bioinformatic algorithms predicted that this variant was deleterious. CONCLUSIONS: A novel missense variant in TUB was identified, which was probably the pathogenic basis for arRP in this consanguineous family. This is the first report of a homozygous missense variant in TUB for RP.

Three Cases of Joubert Syndrome in a Consanguineous Syrian Family and a Interesting Case of Multinational Collaboration.

Joubert syndrome (JS) is a rare congenital, autosomal recessive disorder characterized by a distinctive brain malformation, developmental delay, ocular motor apraxia, breathing abnormalities, and high clinical and genetic heterogeneity. We are reporting three siblings with JS from consanguineous parents in Syria. Two of them had the same homozygous c.2172delA (p.Trp725Glyfs*) AHI1 mutation and the third was diagnosed prenatally with magnetic resonance imaging. This pathogenic variant is very rare and described in only a few cases in the literature. Multinational collaboration could be of benefit for the patients from undeveloped, low-income countries that have a low-quality health care system, especially for the diagnosis of rare diseases.

Exome Sequencing Identifies a Biallelic GALNS Variant (p.Asp233Asn) Causing Mucopolysaccharidosis Type IVA in a Pakistani Consanguineous Family.

Mucopolysaccharidoses (MPS) type IVA is a lysosomal storage disease that mainly affects the skeletal system and is caused by a deficiency of the enzyme N-acetylgalactosamine-6-sulfatase (GALNS). The condition can mistakenly be diagnosed as a primary skeletal dysplasia such as spondylo-epiphyseal dysplasia, which shares many similar phenotypic features. Here, we utilised whole exome sequencing to make the diagnosis of MPS IVA in a resource poor country. We report for the first time the identification of a biallelic GALNS missense variant (c.697G>A, p.Asp233Asn) in the Pakistani population and highlight the potential contribution that academic institutions can make in rare disease diagnosis in the absence of a developed clinical genetic service.

Familial Early-Onset Alzheimer's Caused by Novel Genetic Variant and APP Duplication: A Cross-Sectional Study.

BACKGROUND: The clinical characteristics of symptomatic and asymptomatic carriers of early- onset autosomal dominant Alzheimer's (EOADAD) due to a yet-undescribed chromosomal rearrangement may add to the available body of knowledge about Alzheimer's disease and may enlighten novel and modifier genes. We report the clinical and genetic characteristics of asymptomatic and symptomatic individuals carrying a novel APP duplication rearrangement. METHODS: Individuals belonging to a seven-generation pedigree with familial cognitive decline or intracerebral hemorrhages were recruited. Participants underwent medical, neurological, and neuropsychological evaluations. The genetic analysis included chromosomal microarray, Karyotype, fluorescence in situ hybridization, and whole genome sequencing. RESULTS: Of 68 individuals, six females presented with dementia, and four males presented with intracerebral hemorrhage. Of these, nine were found to carry Chromosome 21 copy number gain (chr21:27,224,097-27,871,284, GRCh37/hg19) including the APP locus (APP-dup). In seven, Chromosome 5 copy number gain (Chr5: 24,786,234-29,446,070, GRCh37/hg19) (Chr5-CNG) cosegregated with the APP-dup. Both duplications co-localized to chromosome 18q21.1 and segregated in 25 pre-symptomatic carriers. Compared to non-carriers, asymptomatic carriers manifested cognitive decline in their mid-thirties. A third of the affected individuals carried a diagnosis of a dis-immune condition. CONCLUSION: APP extra dosage, even in isolation and when located outside chromosome 21, is pathogenic. The clinical presentation of APP duplication varies and may be gender specific, i.e., ICH in males and cognitive-behavioral deterioration in females. The association with immune disorders is presently unclear but may prove relevant. The implication of Chr5-CNG co-segregation and the surrounding chromosome 18 genetic sequence needs further clarification.

Case Report: A Boy From a Consanguineous Family Diagnosed With Congenital Muscular Dystrophy Caused by Integrin Alpha 7 (ITGA7) Mutation.

Introduction: Congenital muscular dystrophy (CMD) is a group of early-onset disorders with clinical and genetic heterogeneity. Patients always present with muscle weakness typically from birth to early infancy, delay or arrest of gross motor development, and joint and/or spinal rigidity. There are various genes related to the development of CMD. Among them, mutations in integrin alpha 7 (ITGA7) is a rare subtype. The identification of disease-causing genes facilitates the diagnosis and treatment of CMD. Methods: We screened ITGA7 mutations in four people by whole exome sequencing and targeted sequencing from a consanguineous family. We then carried out electromyography and neuroelectrophysiological examinations to clarify a clinical picture of the patient diagnosed with CMD. Results: We report a Chinese boy diagnosed with CMD who carries a homozygous variant (c.1088dupG, p.H364Sfs*15) of the ITGA7 gene. According to the genotype analysis of his family members, this is an autosomal recessive inheritance. Conclusions: Our case further shows that ITGA7 mutation is related to CMD. Genetic counseling and multidisciplinary management of CMD play an important role in helping patients and their family. Further elucidation of the significant clinical and genetic heterogeneity, therapeutic targets, and the clinical care for patients remains our challenge for the future.

Novel Mutations in CFAP44 and CFAP43 Cause Multiple Morphological Abnormalities of the Sperm Flagella (MMAF).

Multiple morphological abnormalities of the sperm flagella (MMAF) is a rare disease that causes primary infertility. However, the genetic causes for approximately half of MMAF cases are unknown. Whole exome sequencing analysis of the 27 patients with MMAF identified several CFAP44 mutations (3 homozygous: c.2935_2944del: p.D979*, c.T1769A: p.L590Q, c.2005_2006del: p.M669Vfs*13; and putative compound heterozygous: c.G3262A: p.G1088S and c.C1718A: p.P573H.) and CFAP43 acceptor splice-site deletion (c.3661-2A>-) mutations in 5 and 1 patients, respectively. Real-time quantitative polymerase chain reaction assays also demonstrated that CFAP44 expression was very weak in patient (P)1 and P3, and CFAP43 expression was lower in P6 than in the control. Immunofluorescence analysis of CFAP43 showed lower CFAP43 protein expression levels in P6 than in the normal control. This study demonstrated that biallelic mutations in CFAP44 and CFAP43 cause MMAF. These results provide researchers with a new insight to understand the genetic etiology of MMAF and to identify new loci for genetic counselling of MMAF.

A homozygous CEP135 mutation is associated with multiple morphological abnormalities of the sperm flagella (MMAF).

Multiple morphological abnormalities of the sperm flagella (MMAF) is a rare disease associated with primary infertility; however, ~50% of the genetic alterations associated with MMAF remain unclear. Here, we reported the case of a 30-year-old infertile male from a consanguineous family. Whole-exome sequencing identified a homozygous mutation in the CEP135 gene (c.A1364T:p.D455V), with CEP135 previously reported to play a role in centriole biogenesis and specifically central pair assembly. D455V-mutated proteins formed protein aggregates in the centrosome and the flagella, which might potentially affect the function of centriole assembly. Moreover, intracytoplasmic sperm injection was performed using sperm from this patient; however, pregnancy failed following embryo transfer. This represents the first report of a homozygous mutation of CEP135 associated with MMAF. These results provide researchers and clinicians with a deeper understanding of the gene involved with MMAF and will help predict and assess pregnancy outcomes associated with in vitro fertilization.