[Analysis of a Chinese pedigree with Bw subtype due to a novel variant of α-1,3-N-acetylgalactosaminyltransferase gene].

OBJECTIVE: To explore the serological characteristics and genetic variant in a Chinese pedigree with Bw subtype. METHODS: A 32-year-old female proband who had undergone prenatal examination on December 10, 2020 at the 960th Hospital of the PLA Joint Logistics Support Force and five members from her pedigree were selected as the study subjects. Peripheral blood samples were collected and subjected to ABO blood group phenotyping with serological methods and ABO blood group genotyping with fluorescent PCR. Genetic testing and haplotype analysis were carried out by direct sequencing of the entire coding region of the ABO gene in the proband and cloned sequencing of exons 1-7. RESULTS: The blood type serology of the proband showed Bw, and her ABO blood type genotype determined by fluorescence PCR was B/O. The direct sequencing results showed that the proband had matched the ABO*O.01.01/ABO*B.01 genotype and carried a c.1A>G variant. Cloned sequencing has confirmed the c.1A>G variant to have occurred in the ABO*B.01 allele. Family analysis revealed that the mother of the proband had an O blood type, her husband had a B phenotype, and her three children had a normal B blood type. DNA sequencing showed that the two sons of the proband had a genotype of ABO*B.01 and c.1A>G/ABO*B.01. The daughter of the proband was ABO*O.01.01/ABO*B.01, whilst her mother was ABO*O.01.01/ABO *O.01.02. The novel c.1A>G variant sequence has been registered with the database with a number MZ076785 1. CONCLUSION: The novel c.1A>G variant of exon 1 of α- 1,3 galactose aminotransferase gene probably underlay the reduced expression of B antigen in this pedigree.

[Genetic analysis of a Chinese pedigree affected with Cowden syndrome due to variant of PTEN gene].

OBJECTIVE: To explore the clinical features and genetic etiology of a Chinese pedigree affected with Cowden syndrome (CS). METHODS: A CS pedigree diagnosed in November 2022 at the Ningde Municipal Hospital Affiliated to Ningde Normal University was selected as the study subject. Clinical data were collected, and genetic testing was carried out for available members. Pathogenicity analysis was carried out for the candidate variant. RESULTS: The proband, a 7-year-old male, was found to have autism and intellectual disability. Whole exome sequencing revealed that he has harbored a c.462_463del (p.F154Lfs25) variant of the PTEN gene. The proband's 35-year-old mother, who was diagnosed with pulmonary hamartomas at our hospital, has manifested with lipomas, nodular goiter, and adenomas. Sanger sequencing confirmed that she was also heterozygous for the c.462_463del (p.F154Lfs25) variant of the PTEN gene. No other family members has carried the same variant. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was classified as pathogenic (PVS1+PM2_Supporting+PM6). CONCLUSION: The newly discovered c.462_463del (p.F154Lfs*25) variant of the PTEN gene probably underlay the CS in this pedigree. CS patients have higher risk for developing malignant tumors. Clinicians should be aware of this condition and emphasize follow-up of the patients.

[Genetic study of a rare Chinese pedigree with a recombination occurring between the HLA-A/C loci in both parents].

OBJECTIVE: To analyze a Chinese pedigree with a recombination occurring between the HLA-A/C loci in both parents. METHODS: A patient who was planning to undergo hematopoietic stem cell transplantation due to "aplastic anemia" in February 2022 was selected as the study subject. Peripheral blood samples were collected from the patient, his parents and brother. HLA-A/C/B/DRB1/DQB1 high-resolution typing was carried out by using sequence-based typing and sequence-specific oligonucleotides. The recombination was identified by pedigree analysis. The HLA haplotype of each individual was identified by genealogical analysis. The parentage possibility was determined by short tandem repeat analysis. HLA-A/C/B/DRB1/DRB345/DQA1/DQB1/DPA1/DPB1 were determined with next-generation high-throughput sequence-based typing. The recombination sites were analyzed by family study. RESULTS: The high parentage possibilities of the family was confirmed by short tandem repeat analysis. Recombination was found between the HLA-A*24:02 A*33:03/C*14:03 in the paternally transmitted haplotype, whilst HLA-A*01:01 A*03:01/C*08:02 was found in the maternally transmitted haplotype, which had resulted in two novel HLA haplotypes in the proband. CONCLUSION: A rare case with simultaneous recombination of the paternal and maternal HLA-A/C loci has been discovered, which may facilitate further study of the mechanisms of the HLA recombination.

Unraveling the genetic tapestry of pediatric sarcomeric cardiomyopathies and masquerading phenocopies in Jordan.

Pediatric cardiomyopathies are mostly attributed to variants in sarcomere-related genes. Unfortunately, the genetic architecture of pediatric cardiomyopathies has never been previously studied in Jordan. We sought to uncover the genetic landscape of 14 patients from nine families with several subtypes of pediatric cardiomyopathies in Jordan using Exome sequencing (ES). Our investigation identified pathogenic and likely pathogenic variants in seven out of nine families (77.8%), clustering in sarcomere-related genes. Surprisingly, phenocopies of sarcomere-related hypertrophic cardiomyopathies were evident in probands with glycogen storage disorder and mitochondrial-related disease. Our study underscored the significance of streamlining ES or expanding cardiomyopathy-related gene panels to identify plausible phenocopies of sarcomere-related cardiomyopathies. Our findings also pointed out the need for genetic testing in patients with cardiomyopathy and their at-risk family members. This can potentially lead to better management strategies, enabling early interventions, and ultimately enhancing their prognosis. Finally, our findings provide an initial contribution to the currently absent knowledge about the molecular underpinnings of cardiomyopathies in Jordan.

Clinical characterizations and molecular genetic study of two co-segregating variants in PDZD7 and PDE6C genes leading simultaneously to non-syndromic hearing loss and achromatopsia.

BACKGROUND: Autosomal recessive non-syndromic hearing loss (NSHL) and cone dystrophies (CODs) are highly genetically and phenotypically heterogeneous disorders. In this study, we applied the whole exome sequencing (WES) to find the cause of HL and COD in an Iranian consanguineous family with three affected individuals. METHODS: Three members from an Iranian consanguineous family who were suffering from NSHL and visual impairment were ascertained in this study. Comprehensive clinical evaluations and genetic analysis followed by bioinformatic and co-segregation studies were performed to diagnose the cause of these phenotypes. Data were collected from 2020 to 2022. RESULTS: All cases showed congenital bilateral NSHL, decreased visual acuity, poor color discrimination, photophobia and macular atrophy. Moreover, cornea, iris and anterior vitreous were within normal limit in both eyes, decreased foveal sensitivity, central scotoma and generalized depression of visual field were seen in three cases. WES results showed two variants, a novel null variant (p.Trp548Ter) in the PDE6C gene causing COD type 4 (Achromatopsia) and a previously reported variant (p.Ile84Thr) in the PDZD7 gene causing NSHL. Both variants were found in the cis configuration on chromosome 10 with a genetic distance of about 8.3 cM, leading to their co-inheritance. However, two diseases could appear independently in subsequent generations due to crossover during meiosis. CONCLUSIONS: Here, we could successfully determine the etiology of a seemingly complex phenotype in two adjacent genes. We identified a novel variant in the PDE6C gene, related to achromatopsia. Interestingly, this variant could cooperatively cause visual disorders: cone dystrophy and cone-rod dystrophy.

Variants in HCFC1 and MN1 genes causing intellectual disability in two Pakistani families.

BACKGROUND: Intellectual disability (ID) is a neurodevelopmental condition affecting around 2% of children and young adults worldwide, characterized by deficits in intellectual functioning and adaptive behavior. Genetic factors contribute to the development of ID phenotypes, including mutations and structural changes in chromosomes. Pathogenic variants in the HCFC1 gene cause X-linked mental retardation syndrome, also known as Siderius type X-linked mental retardation. The MN1 gene is necessary for palate development, and mutations in this gene result in a genetic condition called CEBALID syndrome. METHODS: Exome sequencing was used to identify the disease-causing variants in two affected families, A and B, from various regions of Pakistan. Affected individuals in these two families presented ID, developmental delay, and behavioral abnormalities. The validation and co-segregation analysis of the filtered variant was carried out using Sanger sequencing. RESULTS: In an X-linked family A, a novel hemizygous missense variant (c.5705G > A; p.Ser1902Asn) in the HCFC1 gene (NM_005334.3) was identified, while in family B exome sequencing revealed a heterozygous nonsense variant (c.3680 G > A; p. Trp1227Ter) in exon-1 of the MN1 gene (NM_032581.4). Sanger sequencing confirmed the segregation of these variants with ID in each family. CONCLUSIONS: The investigation of two Pakistani families revealed pathogenic genetic variants in the HCFC1 and MN1 genes, which cause ID and expand the mutational spectrum of these genes.

Effect of the OPHN1 novel variant c.1025+1 G>A on RNA splicing: insights from a minigene assay.

This research analyzes the clinical data, whole-exome sequencing results, and in vitro minigene functional experiments of a child with developmental delay and intellectual disability. The male patient, aged 4, began experiencing epileptic seizures at 3 months post-birth and has shown developmental delay. Rehabilitation training was administered between the ages of one and two. There were no other significant family medical histories. Through comprehensive family exome genetic testing, a hemizygous variant in the 11th exon of the OPHN1 gene was identified in the affected child: c.1025 + 1G > A. Family segregation analysis confirmed the presence of this variant in the patient's mother, which had not been previously reported. According to the ACMG guidelines, this variant was classified as a likely pathogenic variant. In response to this variant, an in vitro minigene functional experiment was designed and conducted, confirming that the mutation affects the normal splicing of the gene's mRNA, resulting in a 56 bp retention on the left side of Intron 11. It was confirmed that OPHN1: c.1025 + 1G > A is the pathogenic cause of X-linked intellectual disabilities in the child, with clinical phenotypes including developmental delay and seizures.

A novel variant in GAS2 is associated with autosomal dominant nonsyndromic hearing impairment in a Chinese family.

Knockout of GAS2 (growth arrest-specific protein 2), causes disorganization and destabilization of microtubule bundles in supporting cells of the cochlear duct, leading to hearing loss in vivo. However, the molecular mechanism through which GAS2 variant results in hearing loss remains unknown. By Whole-exome sequencing, we identified a novel heterozygous splicing variant in GAS2 (c.616-2 A > G) as the only candidate mutation segregating with late-onset and progressive nonsyndromic hearing loss (NSHL) in a large dominant family. This splicing mutation causes an intron retention and produces a C-terminal truncated protein (named GAS2mu). Mechanistically, the degradation of GAS2mu via the ubiquitin-proteasome pathway is enhanced, and cells expressing GAS2mu exhibit disorganized microtubule bundles. Additionally, GAS2mu further promotes apoptosis by increasing the Bcl-xS/Bcl-xL ratio instead of through the p53-dependent pathway as wild-type GAS2 does, indicating that GAS2mu acts as a toxic molecule to exacerbate apoptosis. Our findings demonstrate that this novel variant of GAS2 promotes its own protein degradation, microtubule disorganization and cellular apoptosis, leading to hearing loss in carriers. This study expands the spectrum of GAS2 variants and elucidates the underlying pathogenic mechanisms, providing a foundation for future investigations of new therapeutic strategies to prevent GAS2-associated progressive hearing loss.

Global and local ancestry estimation in a captive baboon colony.

The last couple of decades have highlighted the importance of studying hybridization, particularly among primate species, as it allows us to better understand our own evolutionary trajectory. Here, we report on genetic ancestry estimates using dense, full genome data from 881 olive (Papio anubus), yellow (Papio cynocephalus), or olive-yellow crossed captive baboons from the Southwest National Primate Research Center. We calculated global and local ancestry information, imputed low coverage genomes (n = 830) to improve marker quality, and updated the genetic resources of baboons available to assist future studies. We found evidence of historical admixture in some putatively purebred animals and identified errors within the Southwest National Primate Research Center pedigree. We also compared the outputs between two different phasing and imputation pipelines along with two different global ancestry estimation software. There was good agreement between the global ancestry estimation software, with R2 > 0.88, while evidence of phase switch errors increased depending on what phasing and imputation pipeline was used. We also generated updated genetic maps and created a concise set of ancestry informative markers (n = 1,747) to accurately obtain global ancestry estimates.

A novel variant in the FLCN gene in a Chinese family with Birt-Hogg-Dubé syndrome.

BACKGROUND: This study aimed to identify disease-causing variants within a Chinese family affected by Birt-Hogg-Dubé syndrome (BHDS), which arises from an autosomal dominant inheritance pattern attributed to variants in the folliculin (FLCN) gene, recognized as a tumor suppressor gene. METHODS: A Chinese proband diagnosed with BHDS due to renal tumors underwent next-generation sequencing (NGS), revealing a novel variant in the FLCN gene. Sanger sequencing was subsequently performed on blood samples obtained from family members to confirm the presence of this variant. RESULTS: A novel germline frameshift variant (NM_144997.5:c.977dup) was identified in five individuals among the screened family members, marking the first report of this variant. Additionally, a somatic frameshift variant (NM_144997.5:c.1252del) was detected in the renal tumors of the proband. No variant was detected in unaffected family members. CONCLUSIONS: A novel heterozygous variant was identified in exon 9 of the FLCN gene, which broadens the spectrum of FLCN variants. We recommend that molecular analysis of the FLCN gene be performed in patients with suspected BHDS and their families.

A novel start-loss mutation of the SLC29A3 gene in a consanguineous family with H syndrome: clinical characteristics, in silico analysis and literature review.

BACKGROUND: The SLC29A3 gene, which encodes a nucleoside transporter protein, is primarily located in intracellular membranes. The mutations in this gene can give rise to various clinical manifestations, including H syndrome, dysosteosclerosis, Faisalabad histiocytosis, and pigmented hypertrichosis with insulin-dependent diabetes. The aim of this study is to present two Iranian patients with H syndrome and to describe a novel start-loss mutation in SLC29A3 gene. METHODS: In this study, we employed whole-exome sequencing (WES) as a method to identify genetic variations that contribute to the development of H syndrome in a 16-year-old girl and her 8-year-old brother. These siblings were part of an Iranian family with consanguineous parents. To confirmed the pathogenicity of the identified variant, we utilized in-silico tools and cross-referenced various databases to confirm its novelty. Additionally, we conducted a co-segregation study and verified the presence of the variant in the parents of the affected patients through Sanger sequencing. RESULTS: In our study, we identified a novel start-loss mutation (c.2T > A, p.Met1Lys) in the SLC29A3 gene, which was found in both of two patients. Co-segregation analysis using Sanger sequencing confirmed that this variant was inherited from the parents. To evaluate the potential pathogenicity and novelty of this mutation, we consulted various databases. Additionally, we employed bioinformatics tools to predict the three-dimensional structure of the mutant SLC29A3 protein. These analyses were conducted with the aim of providing valuable insights into the functional implications of the identified mutation on the structure and function of the SLC29A3 protein. CONCLUSION: Our study contributes to the expanding body of evidence supporting the association between mutations in the SLC29A3 gene and H syndrome. The molecular analysis of diseases related to SLC29A3 is crucial in understanding the range of variability and raising awareness of H syndrome, with the ultimate goal of facilitating early diagnosis and appropriate treatment. The discovery of this novel biallelic variant in the probands further underscores the significance of utilizing genetic testing approaches, such as WES, as dependable diagnostic tools for individuals with this particular condition.

Identification of RESP18 Gene Mutations Linked to Hereditary Non-Syndromic Cleft Lip and Palate in a Southern Chinese Family.

BACKGROUND Non-syndromic cleft lip with cleft palate (NSCLP) is one of the most common congenital birth defects worldwide; it causes lifelong problems and imposes burdens on patients and their families. This study aimed to describe the genomic analysis and identification of de novo regulated endocrine-specific protein 18 (RESP18) rs2385404 and rs2385405 gene polymorphisms associated with NSCLP in a southern Chinese family and to improve prevention, treatment, and prognosis of NSCLP. MATERIAL AND METHODS We performed a genome-wide association study (GWAS) to investigate the association of NSCLP phenotype with gene mutation. We investigated a 5-persons NSCLP family to screen the genetic variation of Han nationality in southern Chinese. Whole-genome sequencing (WGS) was used to detect all candidate genetic variants, and whole-exome sequencing (WES) was implemented to further verify mutations. The Clinical Variation Data Base (ClinVar) was employed for screening gene mutations. Finally, Sanger sequencing was applied to verify gene variations. RESULTS The combined analysis of WGS, WES, and ClinVar showed that a total of 9 variation positions overlapped among the 3 study cohorts. Sanger sequencing verified Glu amino acid variation in 2 mutation sites (rs2385404, rs2385405) from the RESP18 gene, which caused abnormal RESP18 function and was associated with hereditary NSCLP. CONCLUSIONS The combined genomic results showed that 2 mutations (rs2385404 and rs2385405) of the RESP18 gene were related to NSCLP in the family. The RESP18 gene may play an important role in the etiology and pathogenesis of cleft lip and palate.

Targeted next-generation sequencing reveals the genetic mechanism of Chinese Marfan syndrome cohort with ocular manifestation.

BACKGROUND: Marfan syndrome (MFS) is a hereditary connective tissue disorder involving multiple systems, including ophthalmologic abnormalities. Most cases are due to heterozygous mutations in the fibrillin-1 gene (FBN1). Other associated genes include LTBP2, MYH11, MYLK, and SLC2A10. There is significant clinical overlap between MFS and other Marfan-like disorders. PURPOSE: To expand the mutation spectrum of FBN1 gene and validate the pathogenicity of Marfan-related genes in patients with MFS and ocular manifestations. METHODS: We recruited 318 participants (195 cases, 123 controls), including 59 sporadic cases and 88 families. All patients had comprehensive ophthalmic examinations showing ocular features of MFS and met Ghent criteria. Additionally, 754 cases with other eye diseases were recruited. Panel-based next-generation sequencing (NGS) screened mutations in 792 genes related to inherited eye diseases. RESULTS: We detected 181 mutations with an 84.7% detection rate in sporadic cases and 87.5% in familial cases. The overall detection rate was 86.4%, with FBN1 accounting for 74.8%. In cases without FBN1 mutations, 23 mutations from seven Marfan-related genes were identified, including four pathogenic or likely pathogenic mutations in LTBP2. The 181 mutations included 165 missenses, 10 splicings, three frameshifts, and three nonsenses. FBN1 accounted for 53.0% of mutations. The most prevalent pathogenic mutation was FBN1 c.4096G>A. Additionally, 94 novel mutations were detected, with 13 de novo mutations in 14 families. CONCLUSION: We expanded the mutation spectrum of the FBN1 gene and provided evidence for the pathogenicity of other Marfan-related genes. Variants in LTBP2 may contribute to the ocular manifestations in MFS, underscoring its role in phenotypic diversity.

The genetic spectrum of NF1 variants in 10 unrelated Chinese families with neurofibromatosis type 1.

OBJECTIVES: To investigate the clinical and genetic features in a cohort of Chinese families with neurofibromatosis type 1 (NF1). METHODS: The clinical information of 21 patients with NF1 in 10 families was retrospectively analyzed. To broaden the genetic spectrum of NF1, multiplex ligation-dependent probe amplification analysis was performed first, followed by the whole-exome sequencing, in order to identify pathogenic or potentially pathogenic variants of NF1 gene in 10 unrelated Chinese families. RESULTS: Nine different NF1 variants were identified in all 10 families. Of these, 7 were known pathogenic variants and included the exon 1 deletion, exons 1-58 deletion, c.5401C>T (p.Q1801*), c.2291-2A>C, c.484C>T (p.Q162*), c.4922G>A (p.W1641*) and c.1019_1020del (p.S340Cfs*25). The 2 novel variants were c.5197T>C (p.S1733P) and c.783_797delinsC (p.K261Nfs*25). The p.S1733P variant was classified as a variant of uncertain significance, while p.K261Nfs*25 was classified as pathogenic. Hence, the positive detection rate of NF1 variants was 100% (10/10). While the truncating variants were responsible for 60.0% (6/10) of the cases, the splicing variant was responsible for 10% (1/10) of the cases. CONCLUSION: We identified 2 novel heterozygous variants (c.5197T>C and c.783_797delinsC) in the NF1 gene, which broadens the genetic spectrum of the NF1 gene.

A novel homozygous missense TTC12 variant identified in an infertile Pakistani man with severe oligoasthenoteratozoospermia and primary ciliary dyskinesia.

TTC12 is a cytoplasmic and centromere-localized protein that plays a role in the proper assembly of dynein arm complexes in motile cilia in both respiratory cells and sperm flagella. This finding underscores its significance in cellular motility and function. However, the wide role of TTC12 in human spermatogenesis-associated primary ciliary dyskinesia (PCD) still needs to be elucidated. Whole-exome sequencing (WES) and Sanger sequencing were performed to identify potentially pathogenic variants causing PCD and multiple morphological abnormalities of sperm flagella (MMAF) in an infertile Pakistani man. Diagnostic imaging techniques were used for PCD screening in the patient. Real-time polymerase chain reaction (RT‒PCR) was performed to detect the effect of mutations on the mRNA abundance of the affected genes. Papanicolaou staining and scanning electron microscopy (SEM) were carried out to examine sperm morphology. Transmission electron microscopy (TEM) was performed to examine the ultrastructure of the sperm flagella, and the results were confirmed by immunofluorescence staining. Using WES and Sanger sequencing, a novel homozygous missense variant (c.C1069T; p.Arg357Trp) in TTC12 was identified in a patient from a consanguineous family. A computed tomography scan of the paranasal sinuses confirmed the symptoms of the PCD. RT-PCR showed a decrease in TTC12 mRNA in the patient's sperm sample. Papanicolaou staining, SEM, and TEM analysis revealed a significant change in shape and a disorganized axonemal structure in the sperm flagella of the patient. Immunostaining assays revealed that TTC12 is distributed throughout the flagella and is predominantly concentrated in the midpiece in normal spermatozoa. In contrast, spermatozoa from patient deficient in TTC12 showed minimal staining intensity for TTC12 or DNAH17 (outer dynein arms components). This could lead to MMAF and result in male infertility. This novel TTC12 variant not only illuminates the underlying genetic causes of male infertility but also paves the way for potential treatments targeting these genetic factors. This study represents a significant advancement in understanding the genetic basis of PCD-related infertility.

[Application of whole exome sequencing technology in the diagnosis of hereditary eye diseases].

Objective: To evaluate the application of whole exome sequencing (WES) in the diagnosis of hereditary eye diseases. Methods: A total of 24 patients who came to the Obstetrics and Gynecology Hospital of Fudan University for reproductive genetic counseling from December 2020 to December 2023 with the main complaint of congenital eye disorders were included in this study. All cases had no known infections or exposure to known teratogenic drugs, karyotype and chromosome microarray analysis (CMA) abnormalities. Genomic DNA was extracted from the peripheral blood of the probands and their family members and tested for WES. Among them, three individual WES and 21 Trio WES were performed. Potential pathogenic sites were screened and analyzed by Sanger sequencing. For RPGRIP1:c.1611+26G>A site, minigene vector was constructed and RT-qPCR was performed to detect the effect of mRNA splicing. Results: A total of 24 families were collected in this study, of which 20 yielded positive results, achieving a diagnosis rate of 83.3% (20/24). The results involved 21 genes and identified 30 distinct variants, 19 of which were new variants reported. Prenatal diagnostic analysis of family 3 revealed that the fetus carried a c.6970G>T heterozygous nonsense mutation in the PRPF8 gene. The results of RT-PCR with the minigene vector at the non-classical splice site in family 24 indicated that the transcription product of the mutant plasmid was partially retained 104 bp in intron 12, resulting in a p.Glu538Valfs*12 alteration of the protein. Conclusions: The high detection rate of WES in the diagnosis of hereditary eye diseases further supports the advantages of its application as an important molecular detection tool for determining the etiology of hereditary eye diseases.

[Ancient DNA speaks]. / L'ADN ancien parle de plus en plus.

Many human DNA sequences have been obtained from ancient remains dating back from several millennia. However, these have low coverage and may contain many errors; this has limited their usefulness for many analyses, in particular the search for Identical By Descent (IBD) segments that is very powerful for detection of kinship. A new method, using imputation from database data and sophisticated statistical analysis, proves able to detect IBD segments (and thus parenthood) in low-quality DNA sequences from individuals linked only by sixth degree parenthood, opening a whole new field of investigation using ancient DNA.

Prenatal diagnosis of familial 3p26.3p25.3 deletion in a pregnancy associated with a favorable fetal outcome and asymptomatic carrier parent and family members in three generations.

OBJECTIVE: We present prenatal diagnosis of familial 3p26.3p25.3 deletion in a pregnancy associated with a favorable fetal outcome and asymptomatic carrier parent and family members in three generations. CASE REPORT: A 35-year-old, gravida 2, para 1, woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age and the carrier of distal 3p deletion. She was phenotypically normal, and there was no family history of congenital anomalies. Amniocentesis revealed a karyotype of 46,XY,del(3)(p26.1). Repeat amniocentesis at 21 weeks of gestation revealed a karyotype of 46,XY,del(3)(p25.3). Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes showed the result of arr 3p26.3p25.3 (117,735-8,709,972) × 1.0 [GRCh37 (hg19)] with an 8.59-Mb deletion of 3p26.3p25.3 encompassing 14 OMIM genes of CHL1, CNTN6, CNTN4, IL5RA, TRNT1, CRBN, SETMAR, SUMF1, ITPR1, BHLHE40, ARL8B, GRM7, LMCD1 and SSUH2. Cytogenetic analysis of parental bloods revealed a karyotype of 46,XX,del (3) (p25.3) in the mother and 46,XY in the father. The woman's 69-year-old mother and her 2-year-old elder son carried the same aberrant chromosome of 3p25.3→p26.3 deletion by conventional cytogenetic analysis but manifested no phenotypic abnormality. aCGH analysis of the peripheral bloods showed that the woman's mother and her elder son had the same 8.59-Mb deletion of 3p26.3p25.3. The woman was advised to continue the pregnancy. At 39 weeks of gestation, a 3040-g healthy male baby was delivered. When follow-up at age 2½ years, the neonate was normal in development and showed no apparent phenotypic abnormality. CONCLUSION: Distal 3p deletion of 3p26.3p25.3 involving the OMIM genes from CHL1 to SSUH2 can be associated with no apparent phenotypic abnormality.

[Clinical phenotypic and genetic analysis of syndrome families with EYA1 gene variants].

Objective:To investigate the clinical phenotype of a family with branchio-oto syndrome （BOS） and to explore the genetic etiology of the syndrome in this family. Methods:Clinical data were collected from a child diagnosed with BOS and his family members. Genomic DNA was extracted from peripheral blood of the proband and his family members. Whole-exome sequencing was performed, and the mutation sites were verified and analyzed by Sanger sequencing. Results:The family consists of two generations with four members, three of whom exhibit the phenotype. Two members have hearing loss and bilateral preauricular fistulas and bilateral branchial cleft fistulas. One member has bilateral preauricular fistulas and bilateral branchial cleft fistulas. All of which were in line with the clinical diagnosis of gill ear syndrome, the inheritance mode of the family was autosomal dominant inheritance, genetic testing showed that all members of the family had c. 1744delC（p. L592Cfs*47） mutation in the EYA1 gene, while unaffected members have the wild-type allele at this locus. This mutation is a frameshift mutation, which results in the early appearance of the stop codon, and has not been reported so far. According to ACMG guidelines, the variant was preliminarily determined to be suspected pathogenic. Conclusion:The newly discovered EYA1c. 1744delC（p. L592Cfs*47） mutation in this family is the pathogenic mutant gene of the patients in this family, which further expands the mutation spectrum of EYA1 gene, gives us a new understanding of the disease, and provides an important reference for clinical diagnosis and genetic counseling.

Identifying genetic defects in oculocutaneous albinism patients of West Bengal, Eastern India.

BACKGROUND: Oculocutaneous albinism (OCA) is a congenital heterogeneous group of autosomal recessive disorders characterized by the absence or loss of melanin in the skin, eyes and hair of the affected individuals. Based on the mutated gene, OCA has been classified into eight sub-types (OCA1-8) with overlapping clinical phenotypes. Mutations in the TYR gene cause OCA1, the most prevalent OCA worldwide including India. Mutations in OCA2 and SLC45A2, both of which regulate melanosomal pH that is critical to TYR activity, cause OCA2 and OCA4 respectively, the other common OCA subtypes in India. METHODS: In the present study, we have included 54 OCA-affected cases from 41 unrelated families representing 16 different marriage/ethnic groups from 17 districts of West Bengal, India. We pursued a PCR-sequencing based approach followed by bioinformatic analysis to identify mutations in TYR, OCA2 and SLC45A2 genes. RESULTS: Mutations were detected in 27 of the 54 (50%) OCA patients from 18 unrelated families, representing 9 different marriage/ethnic groups from 11 districts of West Bengal. Three TYR variants: NM_000372.4: c.391 A > G, NP_000363.1: p. Lys131Glu; NM_000372.4: c.1037G > T; NP_000363.1: p. Gly346Val, NM_000372.4: c.715 C > T; NP_000363.1:p.Arg239Trp was identified for the first time in Eastern Indian OCA cases. A novel nonsense variant: NM_016180.5: c.389 T > A, NP_057264.4: p. Leu130* and a novel synonymous variation NM_016180.5: c.1092 A > G; NP_057264.4: p.364E = were identified in SLC45A2. Additionally, NM_016180.5: c.904A > T; NP_057264.4: p. Thre302Ser was identified for the first time in any Eastern Indian OCA case. We identified 2 previously reported mutations in OCA2. In concordance with previous reports, NM_000372.4: c.832C > T, NP_000363.1: p. (Arg278*) was the commonest TYR mutation. CONCLUSION: The results of our study enrich the mutational spectrum of the known OCA causing genes in Eastern India, which would facilitate accurate diagnosis, familial screening, carrier detection and containment of the disease load.