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Am J Hum Genet ; 108(11): 2052-2070, 2021 11 04.
Article En | MEDLINE | ID: mdl-34739834

Pedigree inference from genotype data is a challenging problem, particularly when pedigrees are sparsely sampled and individuals may be distantly related to their closest genotyped relatives. We present a method that infers small pedigrees of close relatives and then assembles them into larger pedigrees. To assemble large pedigrees, we introduce several formulas and tools including a likelihood for the degree separating two small pedigrees, a generalization of the fast DRUID point estimate of the degree separating two pedigrees, a method for detecting individuals who share background identity-by-descent (IBD) that does not reflect recent common ancestry, and a method for identifying the ancestral branches through which distant relatives are connected. Our method also takes several approaches that help to improve the accuracy and efficiency of pedigree inference. In particular, we incorporate age information directly into the likelihood rather than using ages only for consistency checks and we employ a heuristic branch-and-bound-like approach to more efficiently explore the space of possible pedigrees. Together, these approaches make it possible to construct large pedigrees that are challenging or intractable for current inference methods.

Genotype , Pedigree , Algorithms , Female , Humans , Likelihood Functions , Male , Models, Genetic
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 38(11): 1060-1063, 2021 Nov 10.
Article Zh | MEDLINE | ID: mdl-34729743

OBJECTIVE: To analyze the clinical manifestations and gene variants of patients with blepharophimosis, ptosis and epicanthus inversus syndrome (BPES). METHODS: Clinical data of 7 pedigrees affected with BPES were collected, and genomic DNA was extracted from peripheral blood samples of the probands and their relatives. All exons of the FOXL2 gene were subjected to Sanger sequencing. Those with negative findings were further screened by targeted capture and next generation sequencing (NGS) and microarray analysis. Pathogenicity of candidate variants were predicted by search of PubMed and related databases, and the impact of the variants was interpreted by protein prediction software. Diagnosis was confirmed by clinical phenotype, medical history and mutation analysis. RESULTS: A pathogenic variant was identified in six of the 7 pedigrees, which included four known pathogenic variants and one novel FOXL2 c.299dupA variant. A heterozygous 3q22.3q23 deletion, which encompassed the FOXL2 gene, was identified in another pedigree.As predicted, the c.299dupA frameshift mutation of FOXL2 gene can lead to the premature termination of protein translation, which is pathogenic. CONCLUSION: A novel and 5 known pathogenic variants have been identified in six pedigrees affected with BPES by the combined Sanger sequencing, target capture NGS and microarray analysis. Above findings have enabled genetic counseling and prenatal diagnosis for these pedigrees.

Blepharophimosis , Blepharophimosis/genetics , Forkhead Box Protein L2/genetics , Forkhead Transcription Factors/genetics , Humans , Mutation , Pedigree , Phenotype , Skin Abnormalities , Urogenital Abnormalities
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 38(11): 1077-1080, 2021 Nov 10.
Article Zh | MEDLINE | ID: mdl-34729747

OBJECTIVE: To explore the genetic basis for a pedigree affected with Nance-Horan syndrome. METHODS: Clinical manifestation of the patients was analyzed. Genomic DNA was extracted from peripheral blood samples of the pedigree members and 100 unrelated healthy controls. A panel of genes for congenital cataract was subjected to next-generation sequencing (NGS), and candidate variant was verified by Sanger sequencing and bioinformatic analysis based on guidelines of American College of Medical Genetics and Genomics (ACMG). mRNA expression was determined by reverse transcriptase-PCR (RT-PCR). Linkage analysis based on short tandem repeats was carried out to confirm the consanguinity. RESULTS: A small insertional variant c.766dupC (p.Leu256Profs*21) of the NHS gene was identified in the proband and his affected mother, but not among unaffected members and the 100 healthy controls. The variant was unreported in Human Gene Mutation Database (HGMD) and other databases. Based on the ACMG guideline, the variant is predicted to be pathogenic (PVS1+PM2+PM6+PP4). CONCLUSION: The novel variant c.766dupC of the NHS gene probably underlay the X-linked dominant Nance-Horan syndrome in this pedigree.

Cataract , Genetic Diseases, X-Linked , Tooth Abnormalities , Cataract/congenital , Cataract/genetics , Humans , Mutation , Pedigree , State Medicine
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 38(11): 1101-1105, 2021 Nov 10.
Article Zh | MEDLINE | ID: mdl-34729752

OBJECTIVE: To analyze the phenotype and genetic variant in a pedigree affected with inherited protein C (PC) deficiency. METHODS: The proband and her family members (7 individuals from 3 generations) were tested for plasma protein C activity (PC:A), protein C antigen (PC:Ag) content and other coagulation indicators. All of the 9 exons and flanking sequences of the proband's PROC gene were amplified by PCR and sequenced. Suspected variants were verified by reverse sequencing of the proband and her family members. Bioinformatic software was used to analyze the pathogenicity and conservation of the variant site. Swiss-PdbViewer was used to analyze the three-dimensional model and the interaction with the mutant amino acid. RESULTS: The PC:A and PC:Ag of the proband, her grandmother, father and elder brother were decreased to 55%, 52%, 48%, 51% and 53%, 55%, 50%, 56%, respectively. Genetic analysis showed that the four individuals have all carried heterozygous c.1318C>T (p.Arg398Cys) missense mutation in exon 9 of the PROC gene. The score of MutationTaster was 0.991, PROVEAN was -3.72, and FATHMM was -2.49, all predicted it to be a harmful mutation. Phylogenetic analysis also showed that Arg398 was weakly conservative among homologous species. Protein model analysis showed that, in the wild type, Arg398 can form a hydrogen bond with Glu341 and Lys395 respectively, when it was mutated to Cys398, the hydrogen bond with Glu341 disappears and an additional hydrogen bond was formed with Lys395, which has changed the spatial structure of the protein. CONCLUSION: The heterozygous missense mutation c.1318C>T (p.Arg398Cys) of the PROC gene probably underlay the decreased PC:A and PC:Ag in this pedigree.

Protein C Deficiency , Aged , Female , Heterozygote , Humans , Male , Mutation , Pedigree , Phenotype , Phylogeny , Protein C Deficiency/genetics
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 38(11): 1106-1109, 2021 Nov 10.
Article Zh | MEDLINE | ID: mdl-34729753

OBJECTIVE: To analyze the pathogenic variant of preaxial polydactyly in a Chinese Han pedigree and identify the cause of polydactyly. METHODS: The peripheral blood DNA of the proband and her parents was extracted. The polydactyly-related genes were detected by trio whole exome sequencing, and the suspected pathogenic gene was screened out. Sanger sequencing was applied to other members of the pedigree. RESULTS: The results of gene sequencing showed that the LMBR1 gene had a heterozygous variant of c.423+4909(IVS5)C>T in 6 patients of the pedigree. The same variant was not detected in family members with normal phenotype. Based on the ACMG guidelines, c.423+4909(IVS5)C>T of the LMBR1 gene was predicted to be pathogenic (PM1+PM2+PP1-S(PS)+PP4+PP5). CONCLUSION: The heterozygous C>T variant at position 4909 of intron 5 of the LMBR1 gene probably underlies the disease in this pedigree.

Polydactyly , China , Female , Humans , Mutation , Pedigree , Polydactyly/genetics , Thumb , Whole Exome Sequencing
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 38(11): 1110-1113, 2021 Nov 10.
Article Zh | MEDLINE | ID: mdl-34729754

OBJECTIVE: To provide a basis for genetic counseling and clinical precision therapy by exploring the genetic etiology of a child with recurrent hypoglycemia convulsion accompanied by language retardation. METHODS: Peripheral blood samples were obtained from the proband, his sister and his parents. Whole genomic DNA was extracted and analyzed by the whole exon gene sequencing and confirmed by Sanger sequencing. RESULTS: The proband and his sister were found to carry compound heterozygous variants c.731T>A (p.M244L) and c.928G>A (p.G244S) of the GYS2 gene, which had not been reported in the past, the c.731T>A (p.M244L) site was derived from the maternal heterozygous mutation, while c.928G>A (p.G244S) site from the father heterozygous mutation. CONCLUSION: The compound heterozygous variants c.731T>A (p.M244L) and c.928G>A (p.G244S) of the GYS2 gene were the genetic cause of glycogen storage syndrome type 0 in children, providing basis for family genetic counseling. When the patient had Hypoglycemia often accompanied with convulsions, which was easy to be misdiagnosed as seizures, and the antiepileptic treatment was ineffective. After genetic diagnosis, the seizure can be controlled by improving diet to maintain blood glucose stability.

Glycogen , Siblings , Child , Exons , Heterozygote , Humans , Mutation , Pedigree
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 38(11): 1114-1119, 2021 Nov 10.
Article Zh | MEDLINE | ID: mdl-34729755

OBJECTIVE: To analyze the clinical features and genetic variants of two patients from a pedigree affected with Smith-Lemli-Opitz syndrome and explore their genotype-phenotype correlation. METHODS: Clinical data and family history of the pedigree were collected. Whole exome sequencing was carried out to identify the potential variants. Suspected variants were verified by Sanger sequencing of the family members. RESULTS: The proband and her sister both presented with feeding difficulty, facial dysmorphism, seizures, and mental and speech retardation. The third child of this family presented with feeding difficulty, poor weight gain and severe malnutrition after birth. He had died of unknown cause at 6 months without genetic testing. The fourth child was a healthy boy. Genetic testing showed that both the proband and her sister have carried c.127G>T (p.Val43Phe) and c.820_825del (p.Asn274_Val275del) compound heterozygous variants of the DHCR7 gene (NM_001360.2), but the fourth child carried neither of the variants. The two variants were unreported in the literature and disease-related databases, and were not included in the 1000G and gnomAD databases. The c.820_825del variant may affect the sterol-sensitive region of the DHCR7 protein, which can lead to deletion of two amino acids at positions 247 and 275, causing truncation of the DHCR7 protein. It is speculated that this may affect the stability of protein's spatial conformation, thereby decrease the activity of the enzyme. The c.127G>T variant may affect the first transmembrane region of the protein, which is involved in the transmembrane transport of proteins. Multiple software predicted it to be harmful. Conservation analysis suggested that the three amino acids all locate in a highly conserved region of the protein. In consideration of the clinical phenotype, family history and result of genetic testing, we speculated that both patients had Smith-Lemli-Opitz syndrome due to variants of the DHCR7 gene. CONCLUSION: This pedigree has enriched the phenotypic and genotypic data of Smith-Lemli-Opitz syndrome, which clarified the genetic etiology of the patients and provided a basis for genetic counseling of this pedigree.

Oxidoreductases Acting on CH-CH Group Donors , Smith-Lemli-Opitz Syndrome , China , Female , Genetic Testing , Humans , Male , Mutation , Oxidoreductases Acting on CH-CH Group Donors/genetics , Pedigree , Smith-Lemli-Opitz Syndrome/genetics
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 38(11): 1136-1139, 2021 Nov 10.
Article Zh | MEDLINE | ID: mdl-34729760

OBJECTIVE: To detect pathological variant in a Chinese pedigree affected with X-linked hypophosphatemia (XLH). METHODS: Whole-exome sequencing was carried out to screen genetic variants in the proband and her parents. Candidate variant of the phosphate regulating gene with homologies to endopeptidases on the X chromosome (PHEX) was verified by Sanger sequencing of all members of the pedigree and the 100 healthy controls. Prenatal diagnosis was carried out on chorionic villi sample derived from the fetus of the proband. RESULTS: A c.1256G>A (p. Gly419Glu) variant was identified in the PHEX gene of the proband and all other patients from this pedigree. The same variant was not found among healthy members from this pedigree and the 100 healthy controls. Prenatal diagnosis suggested that the fetus also carried the c.1256G>A (p. Gly419Glu) variant. CONCLUSION: The c.1256G>A (p. Gly419Glu) variant of the PHEX gene probably underlay the pathogenesis of XLH in this family. Discovery of the novel variant has enriched the mutational spectrum of the PHEX gene.

Familial Hypophosphatemic Rickets , China , Female , Humans , Mutation , PHEX Phosphate Regulating Neutral Endopeptidase/genetics , Pedigree , Pregnancy , Prenatal Diagnosis
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 38(11): 1081-1086, 2021 Nov 10.
Article Zh | MEDLINE | ID: mdl-34729748

OBJECTIVE: To explore the genetic pathogenesis of X-linked agammaglobulinemia in two patients for clinical diagnosis and family counseling. METHODS: Data was collected from the patients' family including clinical information, blood immunoglobulin level, as well as classification and subgrouping of B lymphocytes. Gene mutations were screened by whole exome sequencing (WES) through next-generation sequencing (NGS), the result was verified with Sanger sequencing. RESULTS: A BTK c.1627T>C (p.Ser543Pro) variant was found in the pedigree. The phenotype and variant have co-segregated in the pedigree. The variant was not found in population database. The variant has affected in the kinase domain which contained no benign variants and is harmful as predicted through bioinformatic analysis. CONCLUSION: BTK c.1627T>C (p.Ser543Pro) is a pathogenic variant contributing to X-linked agammaglobulinemia in this pedigree. Above finding has provided reproduction guidance for this family.

Agammaglobulinemia , Agammaglobulinaemia Tyrosine Kinase/genetics , Agammaglobulinemia/genetics , DNA Mutational Analysis , Genetic Diseases, X-Linked , Humans , Mutation , Pedigree
BMC Ophthalmol ; 21(1): 401, 2021 Nov 20.
Article En | MEDLINE | ID: mdl-34800980

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.

Cone-Rod Dystrophies , Retinitis Pigmentosa , Animals , China , Cone-Rod Dystrophies/genetics , DNA Mutational Analysis , Eye Proteins/genetics , Female , HEK293 Cells , Humans , Mutation , Pedigree , Retinitis Pigmentosa/diagnosis , Retinitis Pigmentosa/genetics
Medicine (Baltimore) ; 100(41): e27544, 2021 Oct 15.
Article En | MEDLINE | ID: mdl-34731156

INTRODUCTION: Fatal familial insomnia (FFI) is a rare clinical case. The study was mainly to report the clinical symptoms and imaging and genetic characteristics of a FFI case with depression, with relevant literature summarized. PATIENT CONCERNS: A male, aged 57 years old, with mental disorders and progressive memory decline one year before admission. DIAGNOSIS: Clinical manifestations: he had obvious abnormal mental behavior, rapidly progressing dementia symptoms, stubborn insomnia, abnormal movements and laryngeal stridor after falling asleep at night. Imaging and genetic test results: the cranial magnetic resonance imaging showed frontal temporal lobe atrophy; the polysomnography results showed no effective sleep; the 14-3-3 test result of cerebrospinal fluid was negative; the prion protein (PRNP) test showed that the D178N gene locus had mutations. And the patient was finally diagnosed as FFI. INTERVENTIONS: There were no obvious effects in the treatment using medicines such as Risperidone, Olanzapine, Alprazolam, Clonazepam, and Deanxit. OUTCOMES: Mobility dysfunction of the patient was further aggravated. He was no longer able to move around on his own, and there were serious mental disorders. CONCLUSION: PRNP examination is of guiding significance for the diagnosis of the FFI of depression. Hence, it is very necessary to perform PRNP examination in clinical diagnosis of FFI of depression.

Brain/pathology , Depression/diagnosis , Insomnia, Fatal Familial/diagnosis , Insomnia, Fatal Familial/psychology , Prion Proteins/analysis , Adult , Brain/diagnostic imaging , Dementia/diagnosis , Dementia/etiology , Diagnosis, Differential , Disease Progression , Dyskinesias/diagnosis , Dyskinesias/etiology , Humans , Insomnia, Fatal Familial/genetics , Magnetic Resonance Imaging/methods , Male , Middle Aged , Mutation , Pedigree , Polysomnography/methods , Prion Proteins/genetics , Respiratory Sounds/diagnosis , Respiratory Sounds/etiology , Sleep Initiation and Maintenance Disorders/diagnosis , Sleep Initiation and Maintenance Disorders/etiology
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 38(10): 947-950, 2021 Oct 10.
Article Zh | MEDLINE | ID: mdl-34625929

OBJECTIVE: To explore the genetic basis for a pedigree affected with Alport syndrome. METHODS: Next generation sequencing and Sanger sequencing was applied to detect potential variants of the COL4A3, COL4A4 and COL4A5 genes among members from the pedigree and 100 unrelated healthy controls. RESULTS: The proband and his twin brother were found to carry two novel variants, namely c.4953G>A and c.4623C>A, of the COL4A4 gene, which were respectively inherited from her father and mother. The same variants were not detected among the 100 healthy controls and medical literature. Based on the guidelines of the American College of Medical Genetics and Genomics, both the c.4953G>A and c.4623C>A variants were predicted to be pathogenic (PVS1+PM2_supporting+PP1). CONCLUSION: The c.4953G>A and c.4623C>A variants of the COLA4A gene probably underlay the Alport syndrome in this pedigree. Above finding has enriched the spectrum of COLA4A gene variants.

Nephritis, Hereditary , Autoantigens/genetics , Child , Collagen Type IV/genetics , Female , Humans , Male , Mutation , Nephritis, Hereditary/genetics , Pedigree
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 38(10): 951-954, 2021 Oct 10.
Article Zh | MEDLINE | ID: mdl-34625930

OBJECTIVE: To explore the genetic basis for a pedigree affected with congenital sensorineural deafness. METHODS: High-throughput sequencing was carried out to analyze the coding regions of 415 genes associated with hereditary deafness in the proband. Suspected variants were verified by PCR amplification and Sanger sequencing of her parents and sister. RESULTS: The proband was found to have carried a heterozygous c.5131G>A (p.Val1711Ile) variant of the CDH23 gene and a heterozygous c.2884C>T(p.Arg962Cys) variant of the PCDH15 gene, which were respectively inherited from her mother and father. Her sister (with normal hearing) was also heterozygous for the c.5131G>A (p.Val1711Ile) variant of the CDH23 gene but not the c.2884C>T (p.Arg962Cys) variant of the PCDH15 gene. Based on the guidelines of the American College of Medical Genetics and Genomics, both variants were predicted to be likely pathogenic (PS1+PM2+PP3+PP4). CONCLUSION: The c.5131G>A (p.Val1711Ile) variant of the CDH23 gene and c.2884C>T (p.Arg962Cys) variant of the PCDH15 gene probably underlay the pathogenesis of Usher syndrome type 1D/F in this pedigree.

Usher Syndromes , Female , Heterozygote , High-Throughput Nucleotide Sequencing , Humans , Mutation , Pedigree , Usher Syndromes/genetics
Lin Chung Er Bi Yan Hou Tou Jing Wai Ke Za Zhi ; 35(10): 910-913;919, 2021 Oct.
Article Zh | MEDLINE | ID: mdl-34628814

Objective:To test the gene sequence of 3 patients with Waardenburg syndrome(WS) using the next generation sequencing technology in order to explore the possible mechanism of molecular genetics. Methods:Medical histories of the family members were collected. Physical examination, audiological evaluation and CT examination were performed. Peripheral blood was collected and DNA was extracted. The exon region of 159 deafness genes, 6 mitochondrial genes and 3 miRNAs of the proband were tested by next generation sequencing. The mutation sites of the possible pathogenic genes were obtained, subsequently, Sanger sequencing verification was performed on the proband and family members. Results:The first proband had a heterozygous mutation in exon 7 of MITF gene(NM_000248): c.641_643delGAA; The second proband had a heterozygous mutation in exon 10 of MITF gene(NM_001354605): c.1177-1G>A; The third proband had a heterozygous mutation in exon 5 of PAX3 gene(NM_181457): c.587_593delCCTCAGC; The parents of the three probands verified by Sanger sequencing that there was no variation at the corresponding sites, and the above mutations were spontaneous mutations. Conclusion:Next generation sequencing can more comprehensively analyze information of the carried status and genetic rules of the disease-associated gene in WS families, and provide guidance for family reproductives.

MicroRNAs , Waardenburg Syndrome , High-Throughput Nucleotide Sequencing , Humans , Mutation , Pedigree , Waardenburg Syndrome/genetics
Article Zh | MEDLINE | ID: mdl-34666446

Objective: To analyze the clinical manifestations of a patient with branchiootic syndrome(BOS) and her families and to carry out genetic testing in order to specify the biological pathogenesis. Methods: Clinical data of the patient and her families were collected. Genomic DNA in the peripheral blood of the proband and her family members was extracted. All exons of 406 deafness-related susceptible genes as well as their flanking regions were sequenced by high-throughput sequencing, and the mutation sites of the proband and her parents were validated by Sanger sequencing. Results: There were nine members in three generations, of whom four presented with hearing loss, preauricular fistula and branchial fistula which met the diagnostic criteria of BOS. Proband and her mother presented with auricle malformation and inner ear malformation. And no one had abnormalities in the kidneys of all the patients. Pedigree analysis revealed that the mode of inheritance in the family was consistent with the autosomal dominant pattern. Mutational analysis showed that all the affected patients detected a heterozygous frameshift variation c.1255delT in the EYA1 gene, which had not been reported. Genotype and phenotype were co-isolated in this family. Such a frameshift variation produced a premature termination codon, thereby causing premature termination of translation (p.C419VFS*12). ACMG identified that the mutation was pathogenic. This mutation was novel and not detected in controls. A heterozygous missense variation mutation c.403G>A(p.G135S) in EYA1 gene was also detected in three members of this family. ACMG identified that the mutation clinical significance was uncertain. However, two of whom were normal, which seemed the disease was not caused by this mutation in this family. Conclusions: A novel frameshift mutation in EYA1(c.1255delT) is the main molecular etiology of BOS in the Chinese family. This study expands the mutational spectrum of EYA1 gene. The clinical manifestations are heterogeneous among patients in this family. The diagnosis of BOS should combine gene tests with clinical phenotypes analysis.

Branchio-Oto-Renal Syndrome , Branchio-Oto-Renal Syndrome/genetics , DNA Mutational Analysis , Female , Genetic Testing , Humans , Intracellular Signaling Peptides and Proteins/genetics , Mutation , Nuclear Proteins , Pedigree , Protein Tyrosine Phosphatases/genetics
Vestn Oftalmol ; 137(5. Vyp. 2): 367-374, 2021.
Article Ru | MEDLINE | ID: mdl-34669350

The clinical and genetic characteristics of ABCA4-associated inherited retinal diseases have been studied for more than 2 decades, since the identification of the ABCA4 protein in 1978 and the ABCA4 gene in 1997. ABCA4 mutations were initially associated with autosomal recessive Stargardt disease (STGD1). It has now been established that mutations in this gene can cause other inherited retinal diseases, such as cone-rod dystrophy and retinitis pigmentosa. In addition, the phenotypes of ABCA4-associated diseases can vary greatly from the classic presentation of Stargardt disease, from loss of central vision in adolescence to disease with early onset and rapid progression or late onset and milder course. ABCA4-associated diseases are inherited in autosomal recessive manner, i.e. the disease develops only if both alleles of the gene are damaged, one inherited from the father and the other inherited from the mother. As with many other recessive hereditary diseases, which are characterized by a variety of clinical manifestations, the diversity of the phenotypes of ABCA4-associated retinal diseases is explained by combinations of sequence variants in the ABCA4 gene inherited by patients from their parents. Despite the fact that in this respect inherited retinal diseases associated with mutations in the ABCA4 gene do not fundamentally differ from other autosomal recessive traits, due to the structure of the gene and the protein encoded by it, there are a number of features thatshould be taken into account when performing molecular diagnostics, predicting the possibility of manifestation and the course of the disease, and planning the approaches to treatment.

Retinal Diseases , Retinitis Pigmentosa , ATP-Binding Cassette Transporters/genetics , Humans , Mutation , Pedigree , Retina , Stargardt Disease
BMC Ophthalmol ; 21(1): 371, 2021 Oct 19.
Article En | MEDLINE | ID: mdl-34666717

BACKGROUND: Rhodopsin (RHO) is the most well-known genetic cause of autosomal dominant retinitis pigmentosa (adRP). This study aimed to investigate the genetic cause of a large Chinese adRP family and assess the pathogenicity of the detected RHO mutant. METHODS: Routine ocular examinations were conducted on all participants. Next-generation sequencing with targeted capture was performed to screen mutations in 179 genes associated with hereditary retinal diseases and 10 candidate genes. Variants detected by NGS were validated by Sanger sequencing and evaluated for pathogenicity. Fragments of mutant and wild-type RHO were cloned into the pEGFP-N1 vector and were transfected into different cell lines to observe the cellular localization of the Rhodopsin-GFP fusion protein and evaluate the expression of endoplasmic reticulum (ER) stress markers. RT-PCR analysis was used to detect transfected the splicing of X box-binding protein 1 (XBP1) mRNA, which is a critical factor affecting ER stress. RESULTS: Genetic analysis identified a heterozygous missense variant, RHO, c.284 T > C (p.L95P) in this adRP family. Another RHO variant (p.P53R) that we reported previously was also included in further functional assessment. Both misfolded mutant proteins accumulated in the ER in a manner similar to that noted for the classic mutant P23H. Spliced XBP1 was observed in cells transfected with mutants, indicating an increase in ER stress. CONCLUSIONS: Although the p.L95P variant is not a novel change, it was the first variant to be functionally evaluated and reported in Chinese RP patients. The results in our study provide significant evidence to classify the p.L95P mutation as a class II mutation.

Retinitis Pigmentosa , Rhodopsin , Endoplasmic Reticulum Stress/genetics , High-Throughput Nucleotide Sequencing , Humans , Pedigree , Retinitis Pigmentosa/genetics , Rhodopsin/genetics