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Genetic testing for congenital or early-onset hearing loss patients has become a common diagnostic option in many countries. On the other hand, there are few late-onset hearing loss patients receiving genetic testing, as late-onset hearing loss is believed to be a complex disorder and the diagnostic rate for genetic testing in late-onset patients is lower than that for the congenital cases. To date, the etiology of late-onset hearing loss is largely unknown. In the present study, we recruited 48 unrelated Japanese patients with late-onset bilateral sensorineural hearing loss, and performed genetic analysis of 63 known deafness gene using massively parallel DNA sequencing. As a result, we identified 25 possibly causative variants in 29 patients (60.4%). The present results clearly indicated that various genes are involved in late-onset hearing loss and a significant portion of cases of late-onset hearing loss is due to genetic causes. In addition, we identified two interesting cases for whom we could expand the phenotypic description. One case with a novel MYO7A variant showed a milder phenotype with progressive hearing loss and late-onset retinitis pigmentosa. The other case presented with Stickler syndrome with a mild phenotype caused by a homozygous frameshift COL9A3 variant. In conclusion, comprehensive genetic testing for late-onset hearing loss patients is necessary to obtain accurate diagnosis and to provide more appropriate treatment for these patients.

Spastic paraplegia (SPG) is a syndrome characterised by lower limb spasticity, occurring alone or in association with other neurological manifestations. Despite of the new molecular technologies, many patients remain yet undiagnosed. The purpose of this study was to describe the clinical presentation and molecular characteristics of a cohort of 27 patients from 18 different families with SPG in the south of Spain. We used a targeted next-generation sequencing (NGS) approach to study a proband from each family. Variants in SPG11 gene were the most common cause of SPG in our area. We made a genetic diagnosis in 52% of cases, identified 3 novel variants and reclassified one uncertain variant in SPG11 gene as pathogenic variant. We identified a patient with two truncanting mutation in SPG11 gene and late onset disease and report another missense mutation outside of motor domain of KIF1A gene in a family with pure SPG. Our study contributes to enhance the scientific knowledge of SPG. It is important to note the large group of cases (48%) that were not genetically diagnosed in our cohort. Therefore NGS approach is an efficient diagnostic tool, but it still large the number of non-diagnosed subjects, suggesting further genetic heterogeneity.

Mendelian susceptibility to mycobacterial disease (MSMD) is a rare monogenetic disease, which is characterized by susceptibility to some weakly virulent mycobacteria. Here, we explored the pathogenic genes and molecular mechanisms of MSMD patients. We recruited three patients diagnosed with MSMD from two families. Two novel mutations (c.1228A > G, p.K410E and c.2071A > G, p.M691V) in STAT1 gene were identified from two families. The translocation of K410E mutant STAT1 protein into nucleus was not affected. The binding ability between gamma-activating sequence (GAS) and K410E mutant STAT1 protein was significantly reduced, which will reduce the interaction between STAT1 protein with the promoters of target genes. The M691V mutant STAT1 protein cannot translocate into the nucleus after IFN-γ stimulation, which will affect the STAT1 protein form gamma-activating factors (GAF) and bind the GAS in the promoter region of downstream target genes. Taken together, our results showed that the mutation of K410E led to impaired binding of STAT1 to target DNA, and the mutation of M691V prevented the transport of STAT1 into the nucleus, which led to MSMD. Together, we identified two novel mutations (c.1228A > G, p.K410E and c.2071A > G, p.M691V) in STAT1 gene in MSMD patients, and deciphered the molecular mechanism of MSMD caused by STAT1 mutations.

Background: Primary biliary cholangitis (PBC) is a complex disease with high heritability. We investigated the association between human leukocyte antigen (HLA)-DRB1 alleles and PBC in families and sporadic cases to evaluate the genetic components of the disease. Methods: We performed whole exome sequencing in three PBC families. We genotyped HLA-DRB1 and calculated the association between HLA-DRB1 alleles and the encoding amino acid sequences with the clinical features. Results: Ten variants harboured the HLA-DRB1 gene associated with PBC. DRB1 x07:01, 14:01 and 14:05 were highly increased in PBC. Ten coding region polymorphisms were associated with PBC that encode the amino acid variants of HLA-DR beta 54, beta 59 and beta 66 located in the peptide-binding site of the MHC molecule. Glutamine at position 54 was confirmed as a risk amino acid, verifying the results of familial aggregation analysis of PBC families. Discussion: Familial aggregation analysis indicated that HLA-DRB1 is a candidate gene for the risk of disease course. Considering that amino acid variations are critical to peptide-binding properties, they underlie the major component of MHC association with PBC. (c) 2021 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

Mismatch repair-deficient (MMRD) brain tumors are rare among primary brain tumors and can be induced by germline or sporadic mutations. Here, we report 13 MMRD-associated (9 sporadic and 4 Lynch syndrome) primary brain tumors to determine clinicopathological and molecular characteristics and biological behavior. Our 13 MMRD brain tumors included glioblastoma (GBM) IDH-wildtype (n = 9) including 1 gliosarcoma, astrocytoma IDH-mutant WHO grade 4 (n = 2), diffuse midline glioma (DMG) H3 K27M-mutant (n = 1), and pleomorphic xanthoastrocytoma (PXA) (n = 1). Next-generation sequencing using a brain tumor-targeted gene panel, microsatellite instability (MSI) testing, Sanger sequencing for germline MMR gene mutation, immunohistochemistry of MMR proteins, and clinicopathological and survival analysis were performed. There were many accompanying mutations, suggesting a high tumor mutational burden (TMB) in 77%, but TMB was absent in one case of GBM, IDH-wildtype, DMG, and PXA, respectively. MSH2, MLH1, MSH6, and PMS2 mutations were found in 31%, 31%, 31% and 7% of patients, respectively. MSI-high and MSI-low were found in 50% and 8% of these gliomas, respectively and 34% was MSI-stable. All Lynch syndrome-associated GBMs had MSI-high. In addition, 77% (10/13) had histopathologically multinucleated giant cells. The progression-free survival tended to be poorer than the patients with no MMRD gliomas, but the number and follow-up duration of our patients were insufficient to get statistical significance. In the present study, we found that the most common MMRD primary brain tumor was GBM IDH-wildtype. The genetic profile of MMRD GBM was different from that of conventional GBM. MMRD gliomas with TMB and MSI-H may be sensitive to immunotherapy but resistant to temozolomide. Our findings can help develop better treatment options., The authors examined 13 mismatch repair-deficient (MMRD)-associated primary brain tumors to determine molecular characteristics and biological behavior. MMRD occurred after chemotherapy and radiotherapy in two cases. The genetic profile of MMRD glioblastoma was different from that of conventional glioblastoma. Half of the MMRD-gliomas and all Lynch syndrome-associated GBMs were high in microsatellite instability. These tumors had high mutational burdens and tended to have shorter progression-free survival than glioma without MMRD.

The pathogenic variant (PV) or likely pathogenic variant (LPV) BRCA1/2 gene is strongly associated with hereditary breast or ovarian cancer. Therefore, it is important to screen blood relatives to establish preventive modalities and surveillance. This study evaluated the feasibility of targeted cascade genetic testing for family members of BRCA1/2 gene PV or LPV carriers. We screened 18 families for BRCA1/2 gene status via the conventional cascade genetic test (n = 9) and targeted cascade genetic test (n = 9), which targeted the exon region wherein the index patient showed PV or LPV. The pedigree and clinicopathologic characteristics were reviewed and analyzed. All index patients were diagnosed with breast cancer, while the third family members were all healthy. In the conventional cascade test group, 3 index patients and 3 family members had the BRCA1/2 gene PV or LPV. In the targeted cascade test group, 5 family members had same type of BRCA1/2 gene PV or LPV as their index patients. Two families had an identical string of BRCA1/2 gene PV or LPV. Although the targeted cascade genetic test cannot completely characterize the BRCA1/2 gene, it is sufficient for determining its PV or LPV status. This limited genetic test can be used for family members of PV or LPV carriers.

Background ABCB4-gene mutations are responsible for several cholestatic diseases with a heterogeneous clinical spectrum. Aims To analyse phenotype/genotype relationships in ABCB4-mutations. Methods Retrospective characterization of adult patients with ABCB4-variations diagnosed between 2015 and 2020. Genotype-phenotype correlations were analysed and compared with previously reported data. Results Twenty patients from 12 families were included. Thirteen patients presented recurrent elevated liver tests, eight fulfilled Low-Phospholipid-Associated-Cholelithiasis syndrome criteria, five had Intrahepatic Cholestasis of Pregnancy and three patients developed Drug-Induced-Liver-Injury. ABCB4 screening identified eight different mutations. Five patients were homozygotes to the variant c.504T > C. Ten patients had one mutation in heterozygote-state and five patients had two mutations in compound- heterozygosity . Portal fibrosis occurred in two patients. One of these patients presented progressive fibrosis and progression of cholestasis despite ursodeoxycholic-acid treatment, this patient also harbours a ABCB11 polymorphism. Conclusion Although, phenotype-genotype relationships have not been clearly defined, an early diagnosis of ABCB4-variants may have an important role in management decisions and patient outcomes. To our knowledge, we describe a not previously reported deletion (c.1181delT) in ABCB4. The c.504T > C polymorphism, although a silent mutation at the protein level, seems to be associated to different cholestatic diseases. The role of other genes variants, namely ABCB11, as co-factor for progression, needs to be clarified.

Background and Purpose: Mutations in the GMPPB gene affect glycosylation of α-dystroglycan, leading to varied clinical phenotypes. We attempted to delineate the muscle MR imaging spectrum of GMPPB-related Congenital Myasthenic syndrome (CMS) in a single-center cohort study. Objective: To identify the distinct patterns of muscle involvement in GMPPB gene mutations. Methods: We analyzed the muscle MR images of 7 genetically proven cases of GMPPB dystroglycanopathy belonging to three families and studied the potential qualitative imaging pattern to aid in clinico -radiological diagnosis in neuromuscular practice. All individuals underwent muscle MRI (T1, T2, STIR/PD Fat sat. sequences in 1.5 T machine) of the lower limbs. Qualitative assessment and scoring were done for muscle changes using Mercuri staging for fibro-fatty replacement on T1 sequence and Borsato score for myoedema on STIR sequence. Results: All patients were of South Indian origin and presented as slowly progressive childhood to adult-onset fatigable limb-girdle muscle weakness, elevated creatine kinase level, and positive decrement response in proximal muscles. Muscle biopsy revealed features of dystrophy. All patients demonstrated identical homozygous mutation c.1000G > A in the GMPPB gene. MRI demonstrated early and severe involvement of paraspinal muscles, gluteus minimus, and relatively less severe involvement of the short head of the biceps femoris. A distinct proximo-distal gradient of affliction was identified in the glutei, vasti, tibialis anterior and peronei. Also, a postero-anterior gradient was observed in the gracilis muscle. Conclusion: Hitherto unreported, the distinctive MR imaging pattern described here, coupled with relatively slowly progressive symptoms of fatigable limb-girdle weakness, would facilitate an early diagnosis of the milder form of GMPPB- dystroglycanopathy associated with homozygous GMPPB gene mutation.

Background Understanding the overall variant burden in pediatric patients with left ventricular noncompaction (LVNC) has clinical implications. Whole exome sequencing (WES) allows detection of coding variants in both candidate cardiomyopathy genes and those included on commercial panels. Other lines of evidence, including in silico analysis, are necessary to reduce the overwhelming number of variants to those most likely having a phenotypic impact. Methods Five families, including five pediatric probands with LVNC, 5 other affected, and 10 unaffected family members, had WES performed, followed by bioinformatics filtering and Sanger sequencing. Review of the HGMD, variant classification by ACMG guidelines, and clinical information were used to further refine complex genotypes. Results One nonsense and eleven missense variants were identified. In Family 1, affected siblings carried digenic heterozygous variants: E1350K-MYH7 and A276V-ANKRD1. The proband also carried heterozygous W143X-NRG1. Four affected members of Family 2 carried K184Q-MYH7 while unaffected members did not. In Family 3, homozygous A161T-MYH7 and heterozygous P4935T-OBSCN variants were identified in the proband with the latter being absent in his unaffected brother. In Family 4, proband's father and half-sibling have mild hypertrabeculation and carry T3796I-PLEC. The proband, carrying T3796I-PLEC and V2878A-OBSCN, demonstrated higher trabeculation burden. The proband in Family 5 carried four variants, R3247W-PLEC, C92Y-ERG, T1233M-NCOR2, and E54K-HIST1H4B. Application of ACMG criteria and clinical data revealed that W143X-NRG1, P4935T-OBSCN, and V2878A-OBSCN likely have no phenotypic role. Conclusions We report nine variants, including novel T3796I-PLEC and biallelic A161T-MYH7, likely contributing to phenotypes ranging from asymptomatic hypertrabeculation to severe LVNC with heart failure.

Background Mucopolysaccharidosis (MPS) refers to a group of lysosomal storage disorders for which seven types and 11 subtypes are currently recognized. Targeted next-generation sequencing (NGS) offers an important method of disease typing, diagnosis, prenatal diagnosis, and treatment. Methods Gene variations in 48 Chinese MPS patients were evaluated using NGS, and the pathogenicity of the DNA alterations was evaluated using PolyPhen2, SIFT, and Mutation Taster. The effect of amino acid substitution on protein structure was also assessed. Results Four pedigrees with MPS I (8.3%), 28 with MPS II (58.3%), two with MPS IIIA (4.2%), two with MPS IIIB (4.2%), six with MPS IVA (12.5%), one with MPS IVB (2.1%), and five with MPS VI (10.4%) were identified. Of the 69 variations identified, 11 were novel variants (three in IDUA, five in IDS, and three in GALNS), all of which were predicted to be disease-causing except for one, and were associated with impaired protein structure and function. Conclusions Targeted NGS technology is effective for the gene-based testing of MPS disorders, which show high allelic heterogeneity. MPS II was the predominant form in Chinese. Our study expands the existing variation spectrum of MPS, which is important for disease management and genetic counseling.

Background: It is likely that additional genes for hereditary breast cancer can be identified using a discordant sib pair design. Using this design we identified individuals harboring a rare PMS1 c.605G>A variant previously predicted to result in loss of function. Objectives: A family-based design and predictive algorithms were used to prioritize candidate variants possibly associated with an increased risk of hereditary breast cancer. Functional analyses were performed for one of the candidate variants, PMS1 c.605G>A. Methods: 1) 14 discordant sister-pairs from hereditary breast cancer families were identified. 2) Whole exome sequencing was performed and candidate risk variants identified. 3) A rare PMS variant was identified in 2 unrelated affected sisters but no unaffected siblings. 4) Functional analysis of this variant was carried out using targeted mRNA sequencing. Results: Genotype-phenotype correlation did not demonstrate tracking of the variant with cancer in the family. Functional analysis revealed no difference in exon 6 incorporation, which was validated by analyzing PMS1 allele specific expression. Conclusions: The PMS1 c.605G>A variant did not segregate with disease, and there was no variant-dependent impact on PMS1 exon 6 splicing, supporting this variant is likely benign. Functional analyses are imperative to understanding the clinical significance of predictive algorithms.

The etiology of central diabetes insipidus (DI) is classified into (1) idiopathic, (2) familial, and (3) secondary. Of these, familial central diabetes insipidus shows an autosomal dominant inheritance. We herein report a case in which this disease was diagnosed based on a family history of nocturnal enuresis. A 40-year-old man had had symptoms of polydipsia, polyuria and nocturia since childhood and found that his daughter had the same symptoms. Despite reaching nine years old, his daughter's nocturnal enuresis still had not improved, resulting in her consulting a pediatrician. She was suspected of having familial neurohypophyseal diabetes insipidus (FNDI) based on her family history and was referred along with her father for a detailed examination and treatment. A hypertonic saline load test (HSLT) to evaluate the arginine vasopressin (AVP) reaction was performed in both the proband and his daughter. The results showed no increase in AVP levels in response to high plasma osmolality. The water deprivation test (WDT) revealed he was suffering from partial DI. Based on the above findings and considering the possibility of familial central diabetes insipidus, we performed a gene mutation analysis of AVP-neurophysin II (NPII). Both the father and daughter had an exon 2 abnormality in this gene (c232_234delGAG; pGlu78del), and this gene mutation is known to cause NPII protein abnormality, abolishing the function of AVP as a carrier protein. This case was considered to have provided an opportunity to understand the role of an NPII gene abnormality in familial central diabetes insipidus.

Complex I deficiency, the most common respiratory chain defect, is genetically heterogeneous: mutations in 8 nuclear and 7 mitochondrial DNA genes encoding complex I subunits have been described. However, these genes account for disease in only a minority of complex I–deficient patients. We investigated whether there may be an unknown common gene by performing functional complementation analysis of cell lines from 10 unrelated patients. Two of the patients were found to have mitochondrial DNA mutations. The other 8 represented 7 different (nuclear) complementation groups, all but 1 of which showed abnormalities of complex I assembly. It is thus unlikely that any one unknown gene accounts for a large proportion of complex I cases. The 2 patients sharing a nuclear complementation group had a similar abnormal complex I assembly profile and were studied further by homozygosity mapping, chromosome transfers, and microarray expression analysis. NDUFS6, a complex I subunit gene not previously associated with complex I deficiency, was grossly underexpressed in the 2 patient cell lines. Both patients had homozygous mutations in this gene, one causing a splicing abnormality and the other a large deletion. This integrated approach to gene identification offers promise for identifying other unknown causes of respiratory chain disorders.

BACKGROUND Germline autosomal dominant and autosomal recessive mutations in PERP encoding p53 effector related to PMP-22 (PERP), a component of epidermal desmosomes, have been associated with a spectrum of keratodermas. Monoallelic nonsense mutations cause Olmsted syndrome with severe periorificial and palmoplantar keratoderma (PPK). Biallelic recessive frameshift and missense mutations are associated with milder forms of the disease, including generalized erythrokeratoderma and PPK. OBJECTIVES To add new insights into the genotype-phenotype correlations as a consequence of PERP mutations and to provide a comprehensive review of the literature. METHODS Among 26 previously unresolved families within a cohort of 180 extended Iranian families with syndromic or nonsyndromic ichthyosis, two families with shared clinical features were examined by whole-exome sequencing (WES) and genome-wide homozygosity mapping (HM). Mycological and dermatopathological studies were performed to further characterize their atypical phenotypic presentations. RESULTS In two unrelated multiplex consanguineous families affected by ichthyosis, two novel biallelic PERP variants, NM_022121.5, c.89T>C, p.Leu30Pro and c.466G>C, p.Gly156Arg, located inside of genomic homozygosity regions of the probands were detected. Interestingly, some patients had areas of scaly psoriasiform plaques on a background of generalized ichthyosis that appeared during active cutaneous fungal infections. Mycological examinations of these lesions revealed infections caused by Candida albicans, Epidermophyton floccosum, or Trichophyton rubrum. Histopathology of the psoriasiform lesions shared some features with psoriasis, which when combined with clinical presentation, led to incorrect diagnoses of guttate psoriasis or pustular psoriasis. CONCLUSIONS PERP variants in ichthyosis patients can confer susceptibility to recalcitrant cutaneous fungal infections. Additionally, patients with episodic psoriasiform dermatitis in the setting of keratoderma should be considered for PERP genotyping and cutaneous fungal examinations.

OBJECTIVE To characterize the signalment, clinical signs, clinical pathological and histologic findings, and outcome in 8 related Bracchi Italiani with proteinuric kidney disease. ANIMALS 8 client-owned Bracchi Italiani. PROCEDURES Health records submitted to the Bracco Italiano Health Foundation and the Bracco Italiano Club of America between 2012 and 2019 were reviewed for dogs with evidence of nephropathy for which histologic diagnoses were obtained. Pedigree, signalment, clinical signs, diagnostic test results (including microscopic examination of kidney tissue samples collected ante- or postmortem), and outcome were acquired. Results were presented as descriptive statistics. RESULTS The most common clinical sign in affected dogs was inappetence. All dogs were proteinuric, and 4 dogs were azotemic. Seven dogs developed clinical signs of kidney disease and were euthanized a median of 75 days postdiagnosis. Six dogs had glomerular amyloidosis, and 1 dog each had nephrosclerosis and nonamyloidotic fibrillar glomerulopathy. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that the clinical presentation may vary in affected dogs, and proteinuria in young or middle-aged Bracchi Italiani should raise the concern for hereditary nephropathy. Prognosis is likely poor once clinical signs are noted.

Hypohidrotic ectodermal dysplasia (HED) is a rare genetic disorder caused by mutational inactivation of a developmental pathway responsible for generation of tissues of ectodermal origin. The X-linked form accounts for the majority of HED cases and is caused by Ectodysplasin (EDA) pathogenic variants. We performed a combined analysis of 29 X-linked hypohidrotic ectodermal dysplasia (XLHED) families (including 12 from our previous studies). In addition to the classical triad of symptoms including loss (or reduction) of ectodermal structures, such as hair, teeth, and sweat glands, we detected additional HED-related clinical features including facial dysmorphism and hyperpigmentation in several patients. Interestingly, global developmental delay was identified as an unusual clinical symptom in many patients. More importantly, we identified 22 causal pathogenic variants that included 15 missense, four small in-dels, and one nonsense, splice site, and large deletion each. Interestingly, we detected 12 unique (India-specific) pathogenic variants. Of the 29 XLHED families analyzed, 11 (38%) harbored pathogenic variant localized to the furin cleavage site. A comparison with HGMD revealed significant differences in the frequency of missense pathogenic variants; involvement of specific exons and/or protein domains and transition/transversion ratios. A significantly higher proportion of missense pathogenic variants (33%) localized to the EDA furin cleavage when compared to HGMD (7%), of which p.R155C, p.R156C, and p.R156H were detected in three families each. Therefore, the first comprehensive analysis of XLHED from India has revealed several unique features including unusual clinical symptoms and high frequency of furin cleavage site pathogenic variants.

Background The mitochondrial tRNA translation optimization 1 (MTO1) gene, which is closely related to defective mitochondrial oxidative phosphorylation, is an evolutionarily conserved protein expressed in high energy-demanding tissues and is associated with complex oxidative phosphorylation deficiency type 10 (COXPD10) in humans. Related cases and studies are still scarce and have not been reported in the Chinese region. Materials and methods Detailed clinical assessment was applied to the patient. Based on next-generation sequencing technology, we performed whole-exome sequencing of the patient and the parents. Sanger sequencing was used for validation. Bioinformatics software and protein simulations were used to predict the pathogenicity of the variants. Results The patient was diagnosed with a possible association with mitochondrial disease according to the clinical manifestations and physical examination. A novel frameshift mutation c.344delA (p. Asn115Thrfs*11) and a novel point mutation c.1055C > T (p. Thr352Met) in the MTO1 gene were identified. They were found to cause abnormal changes in amino acids and the protein by biochemical tools, indicating it may be pathogenic. Conclusion We present two novel and possibly pathogenic variants in the MTO1 gene in a Chinese Han family.

Objective Axenfeld-Rieger syndrome (ARS) type 3 is a rare autosomal dominant disease, characterized by anterior segment dysgenesis of the eye, hearing loss, and cardiac defects. ARS type 3 is highly associated with FOXC1 mutations, which induces developmental disorders of neural crest cells. Most studies about ARS patients focused on ophthalmologic findings, but details in their hearing loss have not yet been revealed. In this report, we investigated audiological and otological manifestations in the ARS type 3 patient who had the novel heterozygous FOXC1 mutation leading deletion at the forkhead DNA-binding domain. Methods and Results Pure tone audiometry showed bilateral sensorineural hearing loss (SNHL) and audiological examinations confirmed that major dysfunctions existed in the cochlea, rather than the spiral ganglion neurons and the cochlear nerve. CT and MRI revealed the hypoplastic cochlea at both sides. Given that the 6p25 deletion syndrome, lacking one allele of the FOXC1 gene, shows similar, but more severe cochlear malformations than the present case, the FOXC1 mutations might contribute to the hypoplasia and dysfunctions in the cochlea. Conclusion To our knowledge, this is the first report demonstrating that the ARS type 3 patient with the FOXC1 mutation has the hypoplasia and dysfunctions in the cochlea, which results in bilateral SNHL.

Background Thoracic aortic aneurysm and dissection (TAAD) is a hidden-onset but life-threatening disorder with high clinical variability and genetic heterogeneity. In recent years, an increasing number of genes have been identified to be related to TAAD. However, some genes remain uncertain because of limited case reports and/or functional studies. LTBP3 was such an ambiguous gene that was previously known for dental and skeletal dysplasia and then noted to be associated with TAAD. More research on individuals or families harboring variants in this gene would be helpful to obtain full knowledge of the disease and clarify its association with TAAD. Methods A total of 266 TAAD probands with no causative mutations in known genes had been performed wholeexome sequencing (WES) to identify potentially pathogenic variants. In this study, rare LTBP3 variants were the focus of analysis. Results Two compound heterozygous mutations, c.625dup (p.Leu209fs) and c.1965del (p.Arg656fs), in LTBP3 were identified in a TAAD patient along with short stature and dental problems, which was the first TAAD case with biallelic LTBP3 null mutations in an Asian population. Additionally, several rare heterozygous LTBP3 variants were also detected in other sporadic TAAD patients. Conclusion The identification of LTBP3 mutations in TAAD patients in our study provided more clinical evidence to support its association with TAAD, which broadens the gene spectrum of LTBP3. LTBP3 should be considered to be incorporated into the routine genetic analysis of heritable aortopathy, which might help to fully understand its phenotypic spectrum and improve the diagnostic rate of TAAD.

Objective Alström syndrome is an autosomal recessive genetic disease caused by a mutation in the ALMS1 gene. Alström syndrome is clinically characterized by multisystem involvement, including sensorineural deafness, cone-rod dystrophy, nystagmus, obesity, insulin resistance, type 2 diabetes and hypogonadism. The diagnosis is thus challenging for patients without this characteristic set of clinical symptoms. We explored the effectiveness of whole-exome sequencing in the diagnosis of Alström syndrome. Methods A girl with symptoms of Alström syndrome was tested and diagnosed with the disease by whole-exome sequencing. Results Whole-exome sequencing revealed two novel variants, c.6160_6161insAT: p.Lys2054Asnfs*21 (exon 8) and c.10823_10824 delAG:p.Glu 3608Alafs*9 (exon16) in the ALMS1 gene, leading to premature termination codons and the domain of ALMS1 protein. Blood sample testing of her asymptomatic parents revealed them to be heterozygous carriers of the same mutations. Assembly showed that the mutations on both alleles were located in conserved sequences. A review of the ALMS1 gene nonsense mutation status was performed. Conclusion We herein report two novel variants of the ALMS1 gene discovered in a Chinese Alström syndrome patient that expand the mutational spectrum of ALMS1 and provided new insight into the molecular mechanism underlying Alström syndrome. Our findings add to the current knowledge concerning the diagnosis and treatment of Alström syndrome.

Background Comitant strabismus (CS) is a heterogeneous disorder that is a major contributing factor to unilateral childhood-onset visual impairment. Studies have confirmed that genetic factors play an important role in the development of CS. The aim of this study was to identify the genetic cause of non-syndromic familial CS. Methods Fourteen unrelated CS families were recruited for the study. Twelve affected and 2 unaffected individuals from a large four-generation family (CS08) were selected to perform whole genome-wide linkage analysis. Parallel whole-exome sequencing (WES) was conducted in the same family (9 patients and 1 unaffected member) and 31 additional CS cases from 13 other unrelated families. Sanger sequencing was used to determine whether any of the remaining variants co-segregated with the disease phenotype in the corresponding family. Results Based on linkage analysis, CS in family CS08 mapped to a novel region of 34.17 centimorgan (cM) on chromosome 2q22.3-2q32.1 between markers D2S151 and D2S364, with a maximum log odds (LOD) score of 3.54 (theta = 0) at D2S142. Parallel WES identified a heterozygous variant, LRP2 c.335 A > G (p.Q112R), located in such a linkage interval that completely co-segregated with the disease in the family. Furthermore, another novel heterozygous variant (c.7274A > G, p.D2425G) in LRP2 that co-segregated was detected in 2 additional affected individuals from another unrelated family by WES. Both variants are predicted to be damaging by PolyPhen-2, SIFT and MutationTaster, and were absent in 100 ethnically matched normal controls. Conclusion LRP2 is a novel candidate genetic cause of non-syndromic familial CS.

Background Autosomal dominant polycystic kidney disease (ADPKD) is the most common monogenic kidney disorder. Half of the patients would slowly progress to end-stage renal disease. However, the potential target for ADPKD treatment is still lacking. Methods Four ADPKD patients and two healthy family members were included in this study. The peripheral blood samples were obtained and tested by the whole exome sequencing (WES). The autosomal mutations in ADPKD patients were retained as candidate sites. The Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment, and protein–protein interaction network (PPI) analyses were performed by clusterProfiler R package. A dataset containing 18 ADPKD patients and three normal samples were downloaded from the Gene Expression Omnibus (GEO) database and analyzed using the limma R package. Results A total of six mutant genes were identified based on the dominant genetic pattern and most of them had not been reported to be associated with ADPKD. Furthermore, 19 harmful genes were selected according to the harmfulness of mutation. GO and KEGG enrichment analyses showed that the processes of single-organism cellular process, response to stimulus, plasma membrane, cell periphery, and anion binding as well as cyclic adenosine monophosphate (cAMP) signaling pathway and pathways in cancer were significantly enriched. Through integrating PPI and gene expression analyses, acyl-CoA thioesterase 13 (ACOT13), which has not been reported to be related to ADPKD, and prostaglandin E receptor 2 (PTGER2) were identified as potential genes associated with ADPKD. Conclusions Through combination of WES, gene expression, and PPI network analyses, we identified ACOT13 and PTGER2 as potential ADPKD-related genes.

Background and aims Porokeratosis (PK) is a heterogeneous group of cutaneous keratinization disorders and has five clinical subtypes. DSAP is the most common clinical subtype and is characterized by multiple small, annular, anhidrotic, keratotic lesions predominantly on sun-exposed areas of the skin. It is an autosomal dominantly inherited epidermal keratinization disorder. However, studies on its molecular basis is limited. Materials and methods We performed mutation analysis of genes in four pedigrees and three sporadic cases of DSAP in the Chinese population. Genomic DNA was extracted from blood samples obtained from patients, unaffected family members, and 100 unrelated individuals. All exons and flanking intron sequences of the mevalonate kinase (MVK) and farnesyl diphosphate synthase (FDPS) genes were amplified. Results One missense mutation in exon 7 (C.G677A) of the MVK gene was identified in pedigree 3, and one missense mutation in exon 5 (C.C535T) of the FDPS gene was identified in sporadic case 3. No mutation was detected in the MVK and FDPS genes in the remaining three pedigrees and two sporadic cases with DSAP. Conclusion Our results may be useful for genetic counseling and prenatal diagnosis of affected families and for expanding the repertoire of MVK and FDPS mutations underlying DSAP.

Purpose To investigate the genotype and long-term clinical phenotype of patients with Bietti crystalline dystrophy (BCD) in Korea and Japan. Design Retrospective case series. Participants We analyzed 62 patients with clinical features of BCD who harbor pathogenic biallelic CYP4V2 variants in their homozygote or compound heterozygote. Methods Data were collected from patient charts, including age, best-corrected visual acuity (BCVA), Goldmann perimetry results, fundus photography, OCT findings, fundus autofluorescence results, and electroretinography findings. We compared the clinical course of the patients with homozygous c.802-8_810de117insGC [exon7del], the most common mutation in the East Asian population, with those of the patients with other genotypes. Main Outcome Measures Best-corrected visual acuity, visual field (VF), and their changes during follow-up. Results The mean age at the first visit was 55.2 years, with a mean follow-up of 7.1 years. The mean BCVAs at the first and last visits were 0.28 logarithm of the minimum angle of resolution (logMAR) and 0.89 logMAR, respectively. In genetic testing, c.802-8_810de117insGC was detected in 86 of 124 alleles of the patients, and 36 patients were homozygous for this mutation. The age, BCVA, VF area, central foveal thickness, and abnormal hypoautofluorescent area at either the first or last visit were not different between the exon7del homozygotes and the others. The mean BCVA changes per year were 0.089 logMAR in the exon7del homozygotes and 0.089 logMAR in the others. An age- and gender-adjusted linear regression analysis showed no association between the exon7del homozygote status and the rate of vision loss. Characteristic crystalline deposits in the posterior pole were generally observed in younger patients and disappeared over time along with progressive retinochoroidal atrophy. Conclusions Patients with BCD and a homozygote for c.802-8_810de117insGC accounted for more than 50% of this cohort of Korean and Japanese patients, and the clinical effect of this deleterious variant was not severe in the spectrum of CYP4V2 retinopathy.

We report the first pedigree of Lynch syndrome bearing a germ-line MSH2 missense mutation c.1808A>T (Asp603Val). Until now, this missense mutation, in exon 12 of MSH2, was identified as a variant of unknown significance in the International Society for Gastrointestinal Hereditary Tumours database. In vitro induction mutagenesis experiments indicated that the MSH2 mutant protein (Asp603Val) is easily degraded in embryonic stem cells, albeit there is no clinical information concerning this mutant. Our pedigree includes four patients with Lynch syndrome-associated malignancies and clinically matches the Amsterdam II criteria. The proband, a female, first had an endometrial cancer at the age of 49 and then mantle cell lymphoma, colonic and gastric adenocarcinomas and neuroendocrine carcinoma, successively. Her mother also had Lynch syndrome-associated malignancies, including colonic, uterine and gastric cancers, and her elder son had rectal cancer. In the germline of the proband and her son, an MSH2 missense mutation c.1808A>T was discovered. Immunohistochemical analyses indicated that the expression of the MSH2 protein was decreased in the tumors, such as gastric cancer and neuroendocrine carcinoma, due to the missense mutation c.1808A>T. This study showed that the MSH2 missense mutation c.1808A>T (Asp603Val) is a likely pathogenic mutation and is responsible for typical Lynch syndrome-associated malignancies, including neuroendocrine carcinoma.

BACKGROUND Familial exudative vitreoretinopathy (FEVR) is a group of inherited eye diseases characterized by premature arrest of retinal vessel development. The purpose of our study was to characterize the genetic causes and clinical features in eight Chinese families with FEVR using next-generation sequencing (NGS) technology. MATERIALS AND METHODS Eight families with FEVR were included in genetic and clinical analyses. We screened the proband and the parents in eight pedigrees with FEVR using targeted NGS approach and in silico analysis to determine the causative mutation for their family's phenotype. RESULTS Four cases (4/8, 50.0%) were confirmed to harbor mutations in known genes, including 3 novel mutations and one previously reported mutation. Among the detected mutations, TSPAN12 accounted for 75% (3/4). We identified a novel stop codon of TSPAN12, a heterozygous missense mutation NM_012338.4:c.633T>A, NP_036470.1:p.Tyr211Ter involved in highly conserved residues in the proband. Retrospective analysis of its clinical manifestation showed that the mutant carrier presented mild clinical features. CONCLUSIONS We found the novel stop codon mutation p.Tyr211Ter in the TSPAN12, which creates a milder phenotype. Discovery of this novel mutation expands the mutation spectrum of TSPAN12, and would be valuable for future genetic disease diagnosis.

Congenital disorders of glycosylation (CDGs) form a group of rare diseases characterized by hypoglycosylation. We here report the identification of 16 individuals from nine families who have either inherited or de novo heterozygous missense variants in STT3A, leading to an autosomal-dominant CDG. STT3A encodes the catalytic subunit of the STT3A-containing oligosaccharyltransferase (OST) complex, essential for protein N-glycosylation. Affected individuals presented with variable skeletal anomalies, short stature, macrocephaly, and dysmorphic features; half had intellectual disability. Additional features included increased muscle tone and muscle cramps. Modeling of the variants in the 3D structure of the OST complex indicated that all variants are located in the catalytic site of STT3A, suggesting a direct mechanistic link to the transfer of oligosaccharides onto nascent glycoproteins. Indeed, expression of STT3A at mRNA and steady-state protein level in fibroblasts was normal, while glycosylation was abnormal. In S. cerevisiae, expression of STT3 containing variants homologous to those in affected individuals induced defective glycosylation of carboxypeptidase Y in a wild-type yeast strain and expression of the same mutants in the STT3 hypomorphic stt3-7 yeast strain worsened the already observed glycosylation defect. These data support a dominant pathomechanism underlying the glycosylation defect. Recessive mutations in STT3A have previously been described to lead to a CDG. We present here a dominant form of STT3A-CDG that, because of the presence of abnormal transferrin glycoforms, is unusual among dominant type I CDGs. ispartof: AMERICAN JOURNAL OF HUMAN GENETICS vol:108 issue:11 pages:2130-2144 ispartof: location:United States status: published

Background: Pituitary resistance to thyroid hormone (PRTH) is often seen in congenital hypothyroidism (CH), presenting as elevated thyrotropin (TSH) values despite (high-)normal thyroid hormone (TH) values achieved by levothyroxine treatment. In this study, we describe a girl with CH who was referred because of difficulties interpreting thyroid function tests. She was thought to have PRTH associated with CH, but genetic studies discovered a pathogenic variant in THRB, causing resistance to TH (RTH-β). Methods: Clinical, genetic, and biochemical data of the proband's family were collected. Results: The 3-year-old girl was diagnosed with CH due to a homozygous pathogenic c.470del p.(Asn157Thrfs*3) SLC5A5 variant in the neonatal period. She needed a notably high levothyroxine dose to normalize TSH, leading to high free thyroxine levels. There were no signs of hyperthyroidism. Sequencing identified a heterozygous pathogenic c.947G>A p.(Arg316His) THRB variant. Conclusions: To our knowledge, this is the first report of concomitant SLC5A5 and THRB variants causing CH and RTH-β.

The genetic heterogeneity of sensorineural hearing loss (SNHL) is a major hurdle to the detection of disease-causing variants. We aimed to identify underlying causal genes associated with mid-frequency hearing loss (HL), which contributes to less than about 1% of SNHL cases, by whole exome sequencing (WES). Thirty families segregating mid-frequency SNHL, in whom biallelic GJB2 mutations had been previously excluded, were selected from among 851 families in our DNA repository of SNHL. DNA samples from the probands were subjected to WES analysis and searched for candidate variants associated with SNHL. We were able to identify the genetic aetiology in six probands (20%). In total, we found three pathogenic and three likely pathogenic variants in four genes COL4A5, OTOGL, TECTA, TMPRSS3). One proband was a compound heterozygote for a pathogenic variant and a variant of uncertain significance (VUS) in MYO15A gene. To date, MYO15A and TMPRSS3 have not yet been described in association with mid-frequency SNHL. In eight additional probands, eight candidate VUS variants were detected in five genes (DIAPH1, MYO7A, TECTA, TMC1, TSPEAR). Seven of these 16 variants have not yet been published or mentioned in the available databases. The most prevalent gene was TECTA, identified in 23% of all tested families. Furthermore, we confirmed the hypothesis that a substantive portion of cases with this conspicuous audiogram shape is a consequence of a genetic disorder.

Isolated growth hormone (GH) deficiency type I A is a rare autosomal recessive disorder caused by deletion of the GH1 gene and characterized by early onset severe short stature and typical phenotype. Lack of exposure to GH during fetal life often leads to formation of anti-GH antibody following exposure to the least immunogenic recombinant human GH (rhGH). Some patients with circulating ant-GH antibodies demonstrate lack of growth response to GH while others do not. However, the clinical significance of this antibody is unclear hence not routinely recommended. Three siblings born of a consanguineous union were referred to us with severe short stature. They were evaluated and IGHD was diagnosed in all of them. Genetic analysis revealed homozygous 6.7 Kb deletions of GH1 gene in all of them while their parents displayed a pattern of heterozygous 6.7 Kb deletions. rhGH was started at 10, 6 and 17/12 years of age. Their growth and hormonal parameters were monitored throughout the course of treatment. The eldest sibling demonstrated usual growth velocity (9.5 cm/year) after start of therapy that rapidly waned after 1st year (2.5 cm/year). The youngest sibling experienced excellent growth response even after 3rd year (10.3 cm/year) while the middle one displayed sub-optimal response from beginning (6.3cm/year). Change of rhGH brand did not work in the two elder sisters. Such a different growth response with rhGH in three siblings harbouring similar genetic abnormality has not been described earlier. Keywords: Isolated growth hormone deficiency type IA, GH1 gene, Anti-GH antibody.

OBJECTIVE Coatomer subunit alpha (COPA) syndrome, also known as autoinflammatory interstitial lung, joint, and kidney disease, is caused by heterozygous mutations in COPA. We identified a novel COPA variant in 4 patients in one family. We undertook this study to elucidate whether and how the variant causes manifestations of COPA syndrome by studying these 4 patients and by analyzing results from a gene-targeted mouse model. METHODS We performed whole-exome sequencing in 7 family members and measured the type I interferon (IFN) signature of the peripheral blood cells. We analyzed the effects of COPA variants in in vitro experiments and in Copa mutant mice that were generated. RESULTS We identified a heterozygous variant of COPA (c.725T>G, p.Val242Gly) in the 4 affected members of the family. The IFN score was high in the members carrying the variant. In vitro analysis revealed that COPA V242G, as well as the previously reported disease-causing variants, augmented stimulator of interferon genes (STING)-induced type I IFN promoter activities. CopaV242G/+ mice manifested interstitial lung disease and STING-dependent elevation of IFN-stimulated gene expression. In CopaV242G/+ dendritic cells, the STING pathway was not constitutively activated but was hyperactivated upon stimulation, leading to increased type I IFN production. CONCLUSION V242G, a novel COPA variant, was found in 4 patients from one family. In gene-targeted mice with the V242G variant, interstitial lung disease was recapitulated and augmented responses of the STING pathway, leading to an increase in type I IFN production, were demonstrated.

Objective Next generation sequencing (NGS) has expanded the diagnostic paradigm turning the focus to the growth plate. The aim of the study was to determine the prevalence of variants in genes implicated in skeletal dysplasias in probands with short stature and mild skeletal anomalies. Design Clinical and radiological data were collected from 108 probands with short stature and mild skeletal anomalies. Methods A customized skeletal dysplasia NGS panel was performed. Variants were classified using ACMG recommendations and Sherloc. Anthropometric measurements and skeletal anomalies were subsequently compared in those with or without an identified genetic defect. Results Heterozygous variants were identified in 21/108 probands (19.4%). Variants were most frequently identified in ACAN (n = 10) and IHH (n = 7) whilst one variant was detected in COL2A1, CREBBP, EXT1, and PTPN11. Statistically significant differences (P < 0.05) were observed for sitting height/height (SH/H) ratio, SH/H ratio standard deviation score (SDS), and the SH/H ratio SDS >1 in those with an identified variant compared to those without. Conclusions A molecular defect was elucidated in a fifth of patients. Thus, the prevalence of mild forms of skeletal dysplasias is relatively high in individuals with short stature and mild skeletal anomalies, with variants in ACAN and IHH accounting for 81% of the cases. An elevated SH/H ratio appears to be associated with a greater probability in detecting a variant, but no other clinical or radiological feature has been found determinant to finding a genetic cause. Currently, we cannot perform extensive molecular studies in all short stature individuals so detailed clinical and radiological phenotyping may orientate which are the candidate patients to obtain worthwhile results. In addition, detailed phenotyping of probands and family members will often aid variant classification.

The genetic architecture of atrial fibrillation (AF) encompasses low impact, common genetic variants and high impact, rare variants. Here, we characterize a high impact AF-susceptibility allele, KCNQ1 R231H, and describe its transcontinental geographic distribution and history. Induced pluripotent stem cell-derived cardiomyocytes procured from risk allele carriers exhibit abbreviated action potential duration, consistent with a gain-of-function effect. Using identity-by-descent (IBD) networks, we estimate the broad- and fine-scale population ancestry of risk allele carriers and their relatives. Analysis of ancestral migration routes reveals ancestors who inhabited Denmark in the 1700s, migrated to the Northeastern United States in the early 1800s, and traveled across the Midwest to arrive in Utah in the late 1800s. IBD/coalescent-based allele dating analysis reveals a relatively recent origin of the AF risk allele (~5000 years). Thus, our approach broadens the scope of study for disease susceptibility alleles to the context of human migration and ancestral origins., Many rare high-impact variants have been associated with disease, but the origins and functional impact are not always explored. Here, the authors trace the ancestry of a rare high impact atrial fibrillation allele in KCNQ1, and use iPSC-derived cardiomyocytes to characterize the effect of the allele.

Research question How can the effect of genetic mutations that may cause primary female infertility be evaluated? Design Patients and their family members underwent whole-exome sequencing and Sanger sequencing to detect the infertility-causing gene and inheritance pattern. To study the function of mutant proteins in vitro, vectors containing wild-type or mutant TUBB8 cDNA were constructed for transient expression in HeLa cells, and in-vitro transcribed mRNA were used for microinjection in germinal vesicle-stage mouse oocytes. Immunofluorescence staining was used to observe the microtubule structure in HeLa cells or meiotic spindle in mouse oocytes. Results A maternally inherited TUBB8 (Tubulin beta 8 class VIII) mutation (NM_177987.2: c. 959G>A: p. R320H) and a previously reported (NM_177987.2: c. 161C>T: p. A54V) recessive mutation from two infertile female patients were identified. The oocytes from the patient carrying p.A54V mutation failed fertilization, whereas oocytes with p.R320H mutation could be fertilized but showed heavy fragmentation during early development. In vitro, functional assays showed that p. A54V mutant disrupted the microtubule structure in HeLa cells (49.3% of transfected cells) and caused large polar body extrusion in mouse oocytes (27.5%), whereas the p.R320H mutant caused a higher abnormal rate (69.7%) in cultured cells and arrested mouse oocytes at meiosis I (38.7%). Conclusion Two TUBB8 mutations (p.A54V and p.R320H) were identified and their pathogeny was confirmed by in-vitro functional assays.

Background Cone-rod dystrophy (CORD) is a group of inherited retinal dystrophies, characterized by decreased visual acuity, color vision defects, photophobia, and decreased sensitivity in the central visual field. Our study has identified a novel pathogenic variant associated with X-linked cone-rod dystrophy (XLCORD) in a Chinese family. Methods All six family members, including the proband, affected siblings, cousins and female carriers, have underwent thorough ophthalmic examinations. The whole exome sequencing was performed for the proband, followed by Sanger sequencing for spilt-sample validation. A mammalian expression vector (AAV-MCS) with mutated retinitis pigmentosa GTPase regulator (RPGR) sequence was expressed in HEK293 T cells. The mutated protein was verified by Western blotting and immunohistochemistry. Results A novel mutation in the RPGR gene (c.2383G > T, p.E795X) is identified to be responsible for CORD pathogenesis. Conclusions Our findings have expanded the spectrum of CORD-associated mutations in RPGR gene and serve as a basis for genetic diagnosis for X-linked CORD.

Genetic hair disorders, although unusual, are not very rare, and dermatologists often have opportunities to see patients. Significant advances in molecular genetics have led to identifying many causative genes for genetic hair disorders, including the recently identified causative genes, such as LSS and C3ORF52. Many patients have been detected with autosomal recessive woolly hair/hypotrichosis in the Japanese population caused by founder mutations in the LIPH gene. Additionally, many patients with genetic hair disorders caused by other genes have been reported in East Asia including Japan. Understanding genetic hair disorders is essential for dermatologists, and the findings obtained from analyzing these diseases will contribute to revealing the mechanisms of hair follicle morphogenesis and development in humans.

White–Sutton syndrome (WHSUS) is a neurodevelopmental disorder caused by heterozygous loss-of-function variants in POGZ. Through the Deciphering Developmental Disorders study and clinical testing, we identified 12 individuals from 10 families with pathogenic or likely pathogenic variants in POGZ (eight de novo and two inherited). Most individuals had delayed development and/or intellectual disability. We analyzed the clinical findings in our series and combined it with data from 89 previously reported individuals. The results demonstrate WHSUS is associated with variable developmental delay or intellectual disability, increased risk of obesity, visual defects, craniofacial dysmorphism, sensorineural hearing loss, feeding problems, seizures, and structural brain malformations. Our series includes further individuals with rod-cone dystrophy, cleft lip and palate, congenital diaphragmatic hernia, and duplicated renal drainage system, suggesting these are rare complications of WHSUS. In addition, we describe an individual with a novel, de novo missense variant in POGZ and features of WHSUS. Our work further delineates the phenotypic spectrum of WHSUS highlighting the variable severity of this disorder and the observation of familial pathogenic POGZ variants.

Non-obstructive azoospermia (NOA) represents one of the most serious forms of male infertility caused by spermatogenic failure. Despite multiple genes found to be associated with human NOA, the genetic basis of this idiopathic disease remains largely unknown. FBXO43 is a direct inhibitor of the anaphase-promoting complex/cyclosome (APC/C) E3 ligase and crucially important in mouse spermatogenesis. In this study, for the first time, we identified a homozygous nonsense mutation in FBXO43 c.1747C > T:p.Gln583X in two NOA brothers from a Chinese consanguineous family via whole-exome sequencing. FBXO43 was absent from testicular tissue of the proband, and FBXO43-immunostaining signals were invisible in the affected seminiferous tubules. Furthermore, in humans, FBXO43 defects cause meiotic arrest within early diplotene of prophase I. The results here demonstrate the pathogenicity of this loss-of-function mutation and confirmed that spermatocytes were unable to complete meiotic divisions without FBXO43 in humans. In mouse testicular protein extracts, three subunits of the APC/C, including ANAPC2, ANAPC8 and ANAPC10, were validated to interact directly with FBXO43, whereas no interactions were detected for FBXO43 and SKP1. This study furthers our understanding of the genetic basis of human NOA and provides insights into FBXO43 and male infertility.