scholarly journals Alteration of Exon Definition Causes Amelogenesis Imperfecta

2020 ◽  
Vol 99 (4) ◽  
pp. 410-418
Author(s):  
Y.J. Kim ◽  
J. Kang ◽  
F. Seymen ◽  
M. Koruyucu ◽  
H. Zhang ◽  
...  
Keyword(s):  
Rna Splicing ◽  
Tooth Enamel ◽  
Genetic Disorders ◽  
Molecular Genetic ◽  
Amelogenesis Imperfecta ◽  
Compound Heterozygous ◽  
Exon Definition ◽  
Whole Exome ◽  
Exon 1 ◽  
Definition Of

Amelogenesis imperfecta (AI) is a collection of genetic disorders affecting the quality and/or quantity of tooth enamel. More than 20 genes are, so far, known to be responsible for this condition. In this study, we recruited 3 Turkish families with hypomaturation AI. Whole-exome sequence analyses identified disease-causing mutations in each proband, and these mutations cosegregated with the AI phenotype in all recruited members of each family. The AI-causing mutations in family 1 were a novel AMELX mutation [NM_182680.1:c.143T>C, p.(Leu48Ser)] in the proband and a novel homozygous MMP20 mutation [NM_004771.3:c.616G>A, p.(Asp206Asn)] in the mother of the proband. Previously reported compound heterozygous MMP20 mutations [NM_004771.3:c.103A>C, p.(Arg35=) and c.389C>T, p.(Thr130Ile)] caused the AI in family 2 and family 3. Minigene splicing analyses revealed that the AMELX missense mutation increased exonic definition of exon 4 and the MMP20 synonymous mutation decreased exonic definition of exon 1. These mutations would trigger an alteration of exon usage during RNA splicing, causing the enamel malformations. These results broaden our understanding of molecular genetic pathology of tooth enamel formation.

scholarly journals A Novel Homozygous USP53 Splicing Variant Disrupting the Gene Function that Causes Cholestasis Phenotype and Review of the Literature

2021 ◽  
Author(s):  
ALPER GEZDIRICI ◽  
ÖZLEM KALAYCIK ŞENGÜL ◽  
MUSTAFA DOĞAN ◽  
BANU YILMAZ ÖZGÜVEN ◽  
EKREM AKBULUT
Keyword(s):  
Amino Acids ◽  
Splice Variant ◽  
Tertiary Structure ◽  
Stop Codon ◽  
Molecular Genetic ◽  
Autosomal Recessive Inheritance ◽  
Clinical Findings ◽  
Review Of The Literature ◽  
Whole Exome ◽  
Exon 1

Abstract Background: Hereditary cholestasis is a heterogeneous group of liver diseases that mostly show autosomal recessive inheritance. The phenotype of cholestasis is highly variable. Molecular genetic testing offers a useful approach to differentiate different types of cholestasis because some symptoms and findings overlap. Biallelic variants in USP53 have recently been reported in cholestasis phenotype. In this study we aim to characterize clinical findings and biological insights on a novel USP53 splice variant causing cholestasis phenotype and review of the literature. Methods and Results: We reported a novel splice variant (NM_019050.2:c.238-1G>C) in the USP53 gene via whole exome sequencing in a patient with cholestasis phenotype. This variant was confirmed by sanger sequencing and as a result of family segregation analysis; it was found to be a heterozygous state in the parents and the other healthy elder brother of our patient. According to in-silico analyses; the change in the splice region resulted in an increase in the length of exon 1, whereas the stop codon after the additional 3 amino acids (VTF) caused the protein to terminate prematurely. Thus, the mature USP53 protein, consisting of 1.073 amino acids, has been reduced to a small protein of 82 amino acids.Conclusions: We propose a model for the tertiary structure of USP53 for the first time, together with all these data, we support the association of biallelic variants of the USP53 gene with the cholestasis phenotype. We also presented a comparison of previously reported patients with the USP53-associated cholestasis phenotype to contribute to the literature.

scholarly journals A Novel de Novo sp6 Mutation Causes Severe Hypoplastic Ame-Logenesis Imperfecta

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 346
Author(s):  
Youn Jung Kim ◽  
Yejin Lee ◽  
Hong Zhang ◽  
Ji-Soo Song ◽  
Jan C-C. Hu ◽  
...  
Keyword(s):  
Western Blot ◽  
Missense Mutation ◽  
Autosomal Dominant ◽  
De Novo ◽  
Clinical Phenotype ◽  
Tooth Enamel ◽  
Genetic Disorders ◽  
Mrna Level ◽  
Amelogenesis Imperfecta ◽  
Wild Type

Amelogenesis imperfecta (AI) is a heterogeneous group of rare genetic disorders affecting tooth enamel formation. Here we report an identification of a novel de novo missense mutation [c.817_818delinsAT, p.(Ala273Met)] in the SP6 gene, causing non-syndromic autosomal dominant AI. This is the second paper on amelogenesis imperfecta caused by SP6 mutation. Interestingly the identified mutation in this study is a 2-bp variant at the same nucleotide positions as the first report, but with AT instead of AA insertion. Clinical phenotype was much more severe compared to the previous report, and western blot showed an extremely decreased level of mutant protein compared to the wild-type, even though the mRNA level was similar.

scholarly journals Clinical and whole-exome sequencing findings in two siblings from Hani ethnic minority with congenital glycosylation disorders

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Zhen Zhang ◽  
Ti-Long Huang ◽  
Jing Ma ◽  
Wen-Ji He ◽  
Huaiyu Gu
Keyword(s):  
Ethnic Minority ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Chinese Population ◽  
Novel Mutation ◽  
Genetic Disorders ◽  
Central Nervous System Involvement ◽  
Compound Heterozygous ◽  
Case Presentation ◽  
Whole Exome

Abstract Background PMM2-CDG, is the most common N-linked glycosylation disorder and subtype among all CDG syndromes, which are a series of genetic disorders involving the synthesis and attachment of glycoproteins and glycolipid glycans. The mutations of PMM2-CDG might lead to the loss of PMM2, which is responsible for the conversion of mannose 6- phosphate into mannose 1-phosphate. Most patients with PMM2-CDG have central nervous system involvement, abnormal coagulation, and hepatopathy. The neurological symptoms of PMM2-CDG are intellectual disability (ID), cerebellar ataxia, and peripheral neuropathy. Now, over 100 new CDG cases have been reported. However, each type of CDG is very rare, and CDGs are problematic to diagnose. In addition, few CDGs have been reported in the Chinese population. Case presentation Here we present a Hani ethnic minority family including two siblings with congenital glycosylation disorders. Whole-exome sequencing revealed compound heterozygous for one novel mutation (c.241–242 del variant) and previously reported mutation (c.395 T > C) in gene of PMM2. Two mutations were found in proband and her sibling by whole-exome sequencing. The mutations were identified in this family by Sanger sequencing and no mutations were detected in the normal control. Conclusions This is the first report to describe mutations in two siblings of Hani ethnic minority which is one of five ethnic groups found only in Yunnan with a population of more than 1 million.

scholarly journals Novel Mutations in GPR68 and SLC24A4 Cause Hypomaturation Amelogenesis Imperfecta

2021 ◽  
Vol 12 (1) ◽  
pp. 13
Author(s):  
Figen Seymen ◽  
Hong Zhang ◽  
Yelda Kasimoglu ◽  
Mine Koruyucu ◽  
James P. Simmer ◽  
...  
Keyword(s):  
Sanger Sequencing ◽  
Frameshift Mutation ◽  
Tooth Enamel ◽  
Bioinformatic Analysis ◽  
Amelogenesis Imperfecta ◽  
Genetic Condition ◽  
Novel Mutations ◽  
Whole Exome ◽  
Homozygous Nonsense Mutation

Amelogenesis imperfecta (AI) is a rare genetic condition affecting the quantity and/or quality of tooth enamel. Hypomaturation AI is characterized by brownish-yellow discoloration with increased opacity and poorly mineralized enamel prone to fracture and attrition. We recruited three families affected by hypomaturation AI and performed whole exome sequencing with selected individuals in each family. Bioinformatic analysis and Sanger sequencing identified and confirmed mutations and segregation in the families. Family 1 had a novel homozygous frameshift mutation in GPR68 gene (NM_003485.3:c.78_83delinsC, p.(Val27Cysfs*146)). Family 2 had a novel homozygous nonsense mutation in SLC24A4 gene (NM_153646.4:c.613C>T, NP_705932.2:p.(Arg205*)). Family 3 also had a homozygous missense mutation in SLC24A4 gene which was reported previously (c.437C>T, p.(Ala146Val)). This report not only expands the mutational spectrum of the AI-causing genes but also improves our understanding of normal and pathologic amelogenesis.

scholarly journals Identification of a novel homozygous loss-of-function mutation in FUCA1 gene causing severe fucosidosis: A case report

2021 ◽  
Vol 49 (4) ◽  
pp. 030006052110059
Author(s):  
Xinwen Zhang ◽  
Shaozhi Zhao ◽  
Hongwei Liu ◽  
Xiaoyan Wang ◽  
Xiaolei Wang ◽  
...  
Keyword(s):  
Amino Acids ◽  
Lysosomal Storage Disorder ◽  
Autosomal Recessive ◽  
Signs And Symptoms ◽  
Lysosomal Storage ◽  
Loss Of Function ◽  
Wild Type ◽  
Single Nucleotide ◽  
Whole Exome ◽  
Exon 1

Fucosidosis is a rare lysosomal storage disorder characterized by deficiency of α-L-fucosidase with an autosomal recessive mode of inheritance. Here, we describe a 4-year-old Chinese boy with signs and symptoms of fucosidosis but his parents were phenotypically normal. Whole exome sequencing (WES) identified a novel homozygous single nucleotide deletion (c.82delG) in the exon 1 of the FUCA1 gene. This mutation will lead to a frameshift which will result in the formation of a truncated FUCA1 protein (p.Val28Cysfs*105) of 132 amino acids approximately one-third the size of the wild type FUCA1 protein (466 amino acids). Both parents were carrying the mutation in a heterozygous state. This study expands the mutational spectrum of the FUCA1 gene associated with fucosidosis and emphasises the benefits of WES for accurate and timely clinical diagnosis of this rare disease.

scholarly journals Biallelic novel mutations of the COL27A1 gene in a patient with Steel syndrome

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jong Seop Kim ◽  
Hyoungseok Jeon ◽  
Hyeran Lee ◽  
Jung Min Ko ◽  
Yonghwan Kim ◽  
...  
Keyword(s):  
Hip Dysplasia ◽  
Large Deletion ◽  
Compound Heterozygous ◽  
Radial Head Dislocation ◽  
Sequencing Data ◽  
Novel Mutations ◽  
Exome Sequencing Data ◽  
Whole Exome ◽  
Whole Exome Sequencing Data ◽  
Carpal Coalition

AbstractAn 11-year-old Korean boy presented with short stature, hip dysplasia, radial head dislocation, carpal coalition, genu valgum, and fixed patellar dislocation and was clinically diagnosed with Steel syndrome. Scrutinizing the trio whole-exome sequencing data revealed novel compound heterozygous mutations of COL27A1 (c.[4229_4233dup]; [3718_5436del], p.[Gly1412Argfs*157];[Gly1240_Lys1812del]) in the proband, which were inherited from heterozygous parents. The maternal mutation was a large deletion encompassing exons 38–60, which was challenging to detect.

scholarly journals Novel variants in DNAH9 lead to nonsyndromic severe asthenozoospermia

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Dongdong Tang ◽  
Yanwei Sha ◽  
Yang Gao ◽  
Jingjing Zhang ◽  
Huiru Cheng ◽  
...  
Keyword(s):  
Sanger Sequencing ◽  
Sperm Morphology ◽  
Immunofluorescence Staining ◽  
Compound Heterozygous ◽  
Sperm Tail ◽  
Transmission Electron ◽  
Whole Exome ◽  
Detailed Medical History ◽  
Novel Variants ◽  
Common Causes

Abstract Background Asthenozoospermia is one of the most common causes of male infertility, and its genetic etiology is poorly understood. DNAH9 is a core component of outer dynein arms in cilia and flagellum. It was reported that variants of DNAH9 (OMIM: 603330) might cause primary ciliary dyskinesia (PCD). However, variants in DNAH9 lead to nonsyndromic severe asthenozoospermia have yet to be reported. Methods Whole exome sequencing (WES) was performed for two individuals with nonsyndromic severe asthenozoospermia from two non-consanguineous families, and Sanger sequencing was performed to verify the identified variants and parental origins. Sperm routine analysis, sperm vitality rate and sperm morphology analysis were performed according the WHO guidelines 2010 (5th edition). Transmission electron microscopy (TEM, TECNAI-10, 80 kV, Philips, Holland) was used to observe ultrastructures of sperm tail. Quantitative realtime-PCR and immunofluorescence staining were performed to detect the expression of DNAH9-mRNA and location of DNAH9-protein. Furthermore, assisted reproductive procedures were applied. Results By WES and Sanger sequencing, compound heterozygous DNAH9 (NM_001372.4) variants were identified in the two individuals with nonsyndromic severe asthenozoospermia (F1 II-1: c.302dupT, p.Leu101fs*47 / c.6956A > G, p.Asp2319Gly; F2 II-1: c.6294 T > A, p.Phe2098Leu / c.10571 T > A, p.Leu3524Gln). Progressive rates less than 1% with normal sperm morphology rates and normal vitality rates were found in both of the two subjects. No respiratory phenotypes, situs inversus or other malformations were found by detailed medical history, physical examination and lung CT scans etc. Moreover, the expression of DNAH9-mRNA was significantly decreased in sperm from F1 II-1. And expression of DNAH9 is lower in sperm tail by immunofluorescence staining in F1 II-1 compared with normal control. Notably, by intracytoplasmic sperm injection (ICSI), F1 II-1 and his partner successfully achieved clinical pregnancy. Conclusions We identified DNAH9 as a novel pathogenic gene for nonsyndromic severe asthenospermia, and ICSI can contribute to favorable pregnancy outcomes for these patients.

scholarly journals Rare Variants in Autophagy and Non-Autophagy Genes in Late-Onset Pompe Disease: Suggestions of Their Disease-Modifying Role in Two Italian Families

2021 ◽  
Vol 22 (7) ◽  
pp. 3625
Author(s):  
Filomena Napolitano ◽  
Giorgia Bruno ◽  
Chiara Terracciano ◽  
Giuseppina Franzese ◽  
Nicole Piera Palomba ◽  
...  
Keyword(s):  
Pompe Disease ◽  
Rare Variants ◽  
Clinical Symptoms ◽  
Late Onset ◽  
Respiratory Muscles ◽  
Autosomal Recessive Disorder ◽  
Compound Heterozygous ◽  
Enzyme Replacement ◽  
Whole Exome ◽  
Clinical Pictures

Pompe disease is an autosomal recessive disorder caused by a deficiency in the enzyme acid alpha-glucosidase. The late-onset form of Pompe disease (LOPD) is characterized by a slowly progressing proximal muscle weakness, often involving respiratory muscles. In LOPD, the levels of GAA enzyme activity and the severity of the clinical pictures may be highly variable among individuals, even in those who harbour the same combination of GAA mutations. The result is an unpredictable genotype–phenotype correlation. The purpose of this study was to identify the genetic factors responsible for the progression, severity and drug response in LOPD. We report here on a detailed clinical, morphological and genetic study, including a whole exome sequencing (WES) analysis of 11 adult LOPD siblings belonging to two Italian families carrying compound heterozygous GAA mutations. We disclosed a heterogeneous pattern of myopathic impairment, associated, among others, with cardiac defects, intracranial vessels abnormality, osteoporosis, vitamin D deficiency, obesity and adverse response to enzyme replacement therapy (ERT). We identified deleterious variants in the genes involved in autophagy, immunity and bone metabolism, which contributed to the severity of the clinical symptoms observed in the LOPD patients. This study emphasizes the multisystem nature of LOPD and highlights the polygenic nature of the complex phenotype disclosed in these patients.

scholarly journals Non-Syndromic Dentinogenesis Imperfecta Caused by Mild Mutations in COL1A2

2021 ◽  
Vol 11 (6) ◽  
pp. 526
Author(s):  
Yejin Lee ◽  
Youn Jung Kim ◽  
Hong-Keun Hyun ◽  
Jae-Cheoun Lee ◽  
Zang Hee Lee ◽  
...  
Keyword(s):  
Collagen Type ◽  
Molecular Genetic ◽  
Collagen Type I ◽  
Type I ◽  
Dentinogenesis Imperfecta ◽  
Gene Encoding ◽  
Korean Families ◽  
Whole Exome ◽  
Genes Encoding ◽  
Candidate Gene Sequencing

Hereditary dentin defects can be categorized as a syndromic form predominantly related to osteogenesis imperfecta (OI) or isolated forms without other non-oral phenotypes. Mutations in the gene encoding dentin sialophosphoprotein (DSPP) have been identified to cause dentinogenesis imperfecta (DGI) Types II and III and dentin dysplasia (DD) Type II. While DGI Type I is an OI-related syndromic phenotype caused mostly by monoallelic mutations in the genes encoding collagen type I alpha 1 chain (COL1A1) and collagen type I alpha 2 chain (COL1A2). In this study, we recruited families with non-syndromic dentin defects and performed candidate gene sequencing for DSPP exons and exon/intron boundaries. Three unrelated Korean families were further analyzed by whole-exome sequencing due to the lack of the DSPP mutation, and heterozygous COL1A2 mutations were identified: c.3233G>A, p.(Gly1078Asp) in Family 1 and c.1171G>A, p.(Gly391Ser) in Family 2 and 3. Haplotype analysis revealed different disease alleles in Families 2 and 3, suggesting a mutational hotspot. We suggest expanding the molecular genetic etiology to include COL1A2 for isolated dentin defects in addition to DSPP.

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