scholarly journals A Founder Pathogenic Variant of PPIB Unique to Chinese Population Causes Osteogenesis Imperfecta IX

2021 ◽  
Vol 12 ◽  
Author(s):  
Wenting Zhu ◽  
Kai Yan ◽  
Xijing Chen ◽  
Wei Zhao ◽  
Yiqing Wu ◽  
...  
Keyword(s):  
Osteogenesis Imperfecta ◽  
Founder Effect ◽  
Chinese Population ◽  
Disease Incidence ◽  
Genetic Disorder ◽  
Missense Variant ◽  
Bone Fragility ◽  
Pathogenic Variant ◽  
Pathogenic Variants ◽  
Specific Allele

Background: Osteogenesis imperfecta (OI) is a heterogeneous genetic disorder characterized by bone fragility. PPIB pathogenic variants cause a perinatal lethal form of OI type IX. A limited number of pathogenic variants have been reported so far worldwide.Methods: We identified a rare pedigree whose phenotype was highly consistent with OI-IX. Exome sequencing was performed to uncover the causal variants. The variant pathogenicity was classified following the ACMG/AMP guidelines. The founder effect and the age of the variant were assessed.Results: We identified a homozygous missense variant c.509G > A/p.G170D in PPIB in an affected fetus. This variant is a Chinese-specific allele and can now be classified as pathogenic. We estimated the allele frequency (AF) of this variant to be 0.0000427 in a Chinese cohort involving 128,781 individuals. All patients and carriers shared a common haplotype, indicative of a founder effect. The estimated age of variant was 65,160 years. We further identified pathogenic variants of PPIB in gnomAD and ClinVar databases, the conserved estimation of OI type IX incidence to be 1/1,000,000 in Chinese population.Conclusion: We reported a founder pathogenic variant in PPIB specific to the Chinese population. We further provided our initial estimation of OI-IX disease incidence in China.

scholarly journals A Novel Missense Variant in the Gene PPP2R5D Causes a Rare Neurodevelopmental Disorder with Increased Phenotype

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Lulu Yan ◽  
Ru Shen ◽  
Zongfu Cao ◽  
Chunxiao Han ◽  
Yuxin Zhang ◽  
...  
Keyword(s):  
De Novo ◽  
Genetic Disorder ◽  
Neurodevelopmental Disorder ◽  
Three Dimensional ◽  
Missense Variant ◽  
Pathogenic Variant ◽  
Dimensional Structure ◽  
Chinese Family ◽  
Speech Impairment ◽  
Pathogenic Variants

PPP2R5D-related neurodevelopmental disorder, which is mainly caused by de novo missense variants in the PPP2R5D gene, is a rare autosomal dominant genetic disorder with about 100 patients and a total of thirteen pathogenic variants known to exist globally so far. Here, we present a 24-month-old Chinese boy with developmental delay and other common clinical characteristics of PPP2R5D-related neurodevelopmental disorder including hypotonia, macrocephaly, intellectual disability, speech impairment, and behavioral abnormality. Trio-whole exome sequencing (WES) and Sanger sequencing were performed to identify the causal gene variant. The pathogenicity of the variant was evaluated using bioinformatics tools. We identified a novel pathogenic variant in the PPP2R5D gene (c.620G>T, p.Trp207Leu). The variant is located in the variant hotspot region of this gene and is predicted to cause PPP2R5D protein dysfunction due to an increase in local hydrophobicity and unstable three-dimensional structure. We report a novel pathogenic variant of PPP2R5D associated with PPP2R5D-related neurodevelopmental disorder from a Chinese family. Our findings expanded the phenotypic and mutational spectrum of PPP2R5D-related neurodevelopmental disorder.

scholarly journals First report of X-linked hypohidrotic ectodermal dysplasia with a hemizygous c.1142G > C in the EDA gene: variant of uncertain significance or new pathogenic variant?

2021 ◽  
Vol 47 (1) ◽  
Author(s):  
Mario Tumminello ◽  
Antonella Gangemi ◽  
Federico Matina ◽  
Melania Guardino ◽  
Bianca Lea Giuffrè ◽  
...  
Keyword(s):  
Ectodermal Dysplasia ◽  
Genetic Disorder ◽  
Missense Variant ◽  
Pathogenic Variant ◽  
Hypohidrotic Ectodermal Dysplasia ◽  
Variant Of Uncertain Significance ◽  
Uncertain Significance ◽  
Clinical Potential ◽  
Genomic Variant ◽  
Eda Gene

Abstract Background Hypohidrotic Ectodermal Dysplasia (HED) is a genetic disorder which affects structures of ectodermal origin. X-linked hypohidrotic ectodermal dysplasia (XLHED) is the most common form of disease. XLHED is characterized by hypotrichosis, hypohydrosis and hypodontia. The cardinal features of classic HED become obvious during childhood. Identification of a hemizygous EDA pathogenic variant in an affected male confirms the diagnosis. Case presentation We report on a male newborn with the main clinical characteristics of the X-linked HED including hypotrichosis, hypodontia and hypohidrosis. Gene panel sequencing identified a new hemizygous missense variant of uncertain significance (VUS) c.1142G > C (p.Gly381Ala) in the EDA gene, located on the X chromosome and inherited from the healthy mother. Conclusion Despite the potential functional impact of VUS remains uncharacterized, our goal is to evaluate the clinical potential consequences of missense VUS on EDA gene. Even if the proband’s phenotype is characteristic for classic HED, further reports of patients with same clinical phenotype and the same genomic variant are needed to consider this novel VUS as responsible for the development of HED.

scholarly journals Dentinogenesis Imperfecta and Caries in Osteogenesis Imperfecta among Vietnamese Children

2021 ◽  
Vol 9 (5) ◽  
pp. 49
Author(s):  
Huong Thi Thu Nguyen ◽  
Dung Chi Vu ◽  
Duc Minh Nguyen ◽  
Quang Dinh Dang ◽  
Van Khanh Tran ◽  
...  
Keyword(s):  
Osteogenesis Imperfecta ◽  
Genetic Disorder ◽  
Collagen Type I ◽  
Bone Fragility ◽  
Open Bite ◽  
Type I ◽  
Dentinogenesis Imperfecta ◽  
Type Iv ◽  
Brown Discoloration ◽  
Study Participants

Osteogenesis imperfecta (OI) is a genetic disorder characterized by increased bone fragility and low bone mass, caused mainly by mutations in collagen type I encoding genes. The current study aimed to evaluate dentinogenesis imperfecta (DI), oral manifestations and caries status of OI children. Sixty-eight children (41 males, 27 females) aged from 3 to 17 years old (mean 9 ± 4.13) participated in the study. Participants were classified into three OI type groups (I—2 cases, III—31 cases and IV—35 cases). Clinical examination and an orthopantomogram were used to obtain prevalences and associations of DI, caries status, malocclusion, crossbite, open bite, eruption, impaction and missing teeth with OI. The prevalence of DI among OI patients was 47.1%, more common in OI type III than type IV. The yellow-brown discoloration type was more vulnerable to attrition than the opalescent-grey one in the primary dentition. OI seemed not to have a high risk of caries; the prevalence of caries was 69.1%. A high incidence of malocclusion, crossbite and open bite was observed. In-depth oral information would provide valuable data for better dental management in OI patients. Parents and general doctors should pay more attention to dental care to prevent caries and premature tooth loss.

Neurosurgical implications of osteogenesis imperfecta in children

2008 ◽  
Vol 1 (3) ◽  
pp. 229-236 ◽  
Author(s):  
Deanna Sasaki-Adams ◽  
Abhaya Kulkarni ◽  
James Rutka ◽  
Peter Dirks ◽  
Michael Taylor ◽  
...  
Keyword(s):  
Osteogenesis Imperfecta ◽  
Genetic Disorder ◽  
Care Center ◽  
Spinal Fractures ◽  
Basilar Invagination ◽  
Bone Fragility ◽  
Shunt Insertion ◽  
Collagen Formation ◽  
Minimal Trauma ◽  
Sick Children

✓Osteogenesis imperfecta (OI) is a rare genetic disorder characterized by disruption of normal collagen formation resulting in varying degrees of skeletal vulnerability, ligamentous laxity, and scleral discoloration. Children with OI may suffer from complex neurosurgical problems affecting the brain and spine. The authors sought to determine the neurosurgical implications of OI in a cohort of patients treated at a quaternary care center for pediatrics. The authors reviewed the case histories of 10 children with OI treated by the neurosurgical service at the Hospital for Sick Children in Toronto between January 1988 and March 2007. The cases of 4 of these children are highlighted in the article. The most common neurosurgical conditions encountered in this cohort included macrocephaly in 5 patients, subdural hematoma in 3 patients, epidural hematoma in 2 patients, and hydrocephalus in 3 patients. Basilar invagination and spinal fractures were observed in 20% of the cohort. Although some patients could be treated nonoperatively, several required craniotomy for clot evacuation, decompression, and spinal fixation for fracture or basilar invagination, and cerebrospinal fluid shunt insertion. Neurosurgical conditions affecting patients with OI include macrocephaly, the development of an acute intracranial hematoma after often minimal trauma, the development of chronic subdural fluid collections that may require drainage, hydrocephalus (both communicating and noncommunicating), basilar invagination, and subaxial spinal fractures. Surgery may be complicated in some children because of the underlying bone fragility and bleeding diathesis commonly observed in patients with OI.

scholarly journals Plastin 3 in X-Linked Osteoporosis: Imbalance of Ca2+-Dependent Regulation Is Equivalent to Protein Loss

2021 ◽  
Vol 8 ◽  
Author(s):  
Christopher L. Schwebach ◽  
Elena Kudryashova ◽  
Dmitri S. Kudryashov
Keyword(s):  
Osteogenesis Imperfecta ◽  
Actin Cytoskeleton ◽  
Bone Development ◽  
Genetic Disorder ◽  
Cellular Structures ◽  
Protein Loss ◽  
Pathogenic Variants ◽  
Recent Advances ◽  
Intracellular Ca

Osteogenesis imperfecta is a genetic disorder disrupting bone development and remodeling. The primary causes of osteogenesis imperfecta are pathogenic variants of collagen and collagen processing genes. However, recently variants of the actin bundling protein plastin 3 have been identified as another source of osteogenesis imperfecta. Plastin 3 is a highly conserved protein involved in several important cellular structures and processes and is controlled by intracellular Ca2+ which potently inhibits its actin-bundling activity. The precise mechanisms by which plastin 3 causes osteogenesis imperfecta remain unclear, but recent advances have contributed to our understanding of bone development and the actin cytoskeleton. Here, we review the link between plastin 3 and osteogenesis imperfecta highlighting in vitro studies and emphasizing the importance of Ca2+ regulation in the localization and functionality of plastin 3.

Osteogenesis Imperfecta

2018 ◽  
Author(s):  
Aimee G. Kakascik
Keyword(s):  
Osteogenesis Imperfecta ◽  
Genetic Disorder ◽  
Bone Fragility ◽  
Type I ◽  
Multiple Fractures ◽  
Systemic Involvement ◽  
Collagen Formation ◽  
Different Types ◽  
Clinical Triad ◽  
Blue Sclerae

Osteogenesis imperfecta (OI) is a genetic disorder that affects collagen formation and ultimately leads to increased bone fragility. The fragile nature of the bones leads to fractures, even from seemingly normal patient care. Affected patients are at the highest risk for unintentional fractures during perioperative care. There are several different types of OI. Type I is the most common. With the different types come varying degrees of severity. Types II and III are the more severe forms. The classic clinical triad seen in OI is blue sclerae, multiple fractures, and conductive hearing loss. The patient may have other systemic involvement beyond the fragile musculoskeletal system. It is imperative that the anesthesiologist be well-versed in the natural history and perioperative management of patients with OI in order to optimize care and minimize complications.

Hearing Loss in Finnish Adults with Osteogenesis Imperfecta: A Nationwide Survey

2002 ◽  
Vol 111 (10) ◽  
pp. 939-946 ◽  
Author(s):  
Kaija Kuurila ◽  
Reijo Johansson ◽  
Ilkka Kaitila ◽  
Reidar Grénman
Keyword(s):  
Hearing Loss ◽  
Osteogenesis Imperfecta ◽  
Clinical Features ◽  
Genetic Disorder ◽  
Nationwide Survey ◽  
Bone Fragility ◽  
Type I ◽  
Impaired Hearing ◽  
Hearing Ability ◽  
Blue Sclerae

Hearing loss, bone fragility, and blue sclerae are the principal clinical features in osteogenesis imperfecta (OI), a genetic disorder of connective tissue. In a nationwide search, an audiometric evaluation of 133 adult patients was performed. According to the criteria introduced by Sillence, type I was the most common form of OI. Of the patients with normal hearing on audiometry, 17.1% reported subjective hearing loss, and 19.1% of the patients with impaired hearing did not recognize it. On audiometry, 57.9% of the patients had hearing loss, which was progressive, often of mixed type, and mostly bilateral, and began in the second to fourth decades of life. The frequency or severity of the hearing loss was not correlated with any other clinical features of OI. Hearing loss is common, affecting patients with all types of OI. Subjective misjudgment of hearing ability supports the need for repeated audiometry in all OI patients. A baseline study at the age of 10 years followed by audiograms every third year thereafter is recommended.

scholarly journals First Report of X-Linked Hypohidrotic Ectodermal Dysplasia with a Hemizygous c.1142G >C in the EDA Gene: Variant of Uncertain Significance or New Pathogenic Variant?

2021 ◽  
Author(s):  
Mario Tumminello ◽  
Antonella Gangemi ◽  
Federico Matina ◽  
Melania Guardino ◽  
Bianca Lea Giuffrè ◽  
...  
Keyword(s):  
Ectodermal Dysplasia ◽  
Genetic Disorder ◽  
Missense Variant ◽  
Pathogenic Variant ◽  
Causative Role ◽  
Hypohidrotic Ectodermal Dysplasia ◽  
Variant Of Uncertain Significance ◽  
Uncertain Significance ◽  
Clinical Potential ◽  
Eda Gene

Abstract BackgroundHypohidrotic Ectodermal Dysplasia (HED) is a genetic disorder which affects structures of ectodermal origin. X-linked hypohidrotic ectodermal dysplasia (XLHED) is the most common form of disease. XLHED Is characterized by hypotrichosis, hypohydrosis and hypodontia. The cardinal features of classic HED become obvious during childhood. Identification of a hemizygous EDA pathogenic variant in an affected male confirms the diagnosis. Case PresentationWe report on a male newborn with the main clinical characteristics of the X-linked HED including hypotrichosis, hypodontia and hypohidrosis. Gene panel sequencing identified a new hemizygous missense variant of uncertain significance (VUS) c.1142G >C (p.Gly318A1a) in the EDA gene, located on the X chromosome and inherited from the healthy mother. ConclusionDespite the potential functional impact of VUS remains uncharacterized, our goal is to evaluate the clinical potential consequences of missense VUS on EDA gene. Given the proband’s phenotype compatibility with classic HED, it is reasonable to attribute a causative role to the variant found in hemizygosis in the gene EDA. The present case demonstrates that this novel VUS could broaden the spectrum of genes mutations involved in the HED phenotype.

scholarly journals Molecular Diagnosis of Neurofibromatosis by Multigene Panel Testing

2021 ◽  
Vol 12 ◽  
Author(s):  
Zeng-Yun-Ou Zhang ◽  
Yuan-Yuan Wu ◽  
Xin-ying Cai ◽  
Wen-Liang Fang ◽  
Feng-Li Xiao
Keyword(s):  
Mutation Rate ◽  
Genetic Disorder ◽  
Missense Variant ◽  
Neurogenic Tumors ◽  
Panel Testing ◽  
Pathogenic Variants ◽  
Clinical Diagnoses ◽  
Exon 1 ◽  
Multigene Panel Testing ◽  
Multigene Panel

Neurofibromatosis (NF) is an autosomal genetic disorder for which early and definite clinical diagnoses are difficult. To identify the diagnosis, five affected probands with suspected NF from unrelated families were included in this study. Molecular analysis was performed using multigene panel testing and Sanger sequencing. Ultradeep sequencing was used to analyze the mutation rate in the tissues from the proband with mosaic mutations. Three different pathogenic variants of the NF1 gene were found in three probands who mainly complained of café-au-lait macules (CALMs), including one frameshift variant c.5072_5073insTATAACTGTAACTCCTGGGTCAGGGAGTACACCAA:p.Tyr1692Ilefs in exon 37, one missense variant c.3826C > T:p.Arg1276Ter in exon 28, and one splicing variant c.4110 + 1G > T at the first base downstream of the 3′-end of exon 30. One NF1 gene mosaic variant was found in a proband who complained of cutaneous neurofibroma with the frameshift variant c.495_498del:p.Thr165fs in exon 5, and ultradeep sequencing showed the highest mutation rate of 10.81% in cutaneous neurofibromas. A frameshift variant, c.36_39del:p.Ser12fs in exon 1 of the NF2 gene, was found in a proband who presented with skin plaques and intracranial neurogenic tumors. All of these pathogenic variants were heterozygous, one was not reported, and one not in Chinese before. This study expands the pathogenic variant spectrum of NF and demonstrates the clinical diagnosis.

scholarly journals Structure and Function of the ABCD1 Variant Database: 20 Years, 940 Pathogenic Variants, and 3400 Cases of Adrenoleukodystrophy

Cells ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 283
Author(s):  
Eric J. Mallack ◽  
Kerry Gao ◽  
Marc Engelen ◽  
Stephan Kemp
Keyword(s):  
Transmembrane Domain ◽  
Missense Variant ◽  
Pathogenic Variant ◽  
Atp Binding ◽  
Pathogenic Variants ◽  
Mutation Database ◽  
Variant Frequency ◽  
Additional Level ◽  
And Function ◽  
Variant Database

The progressive neurometabolic disorder X-linked adrenoleukodystrophy (ALD) is caused by pathogenic variants in the ABCD1 gene, which encodes the peroxisomal ATP-binding transporter for very-long-chain fatty acids. The clinical spectrum of ALD includes adrenal insufficiency, myelopathy, and/or leukodystrophy. A complicating factor in disease management is the absence of a genotype–phenotype correlation in ALD. Since 1999, most ABCD1 (likely) pathogenic and benign variants have been reported in the ABCD1 Variant Database. In 2017, following the expansion of ALD newborn screening, the database was rebuilt. To add an additional level of confidence with respect to pathogenicity, for each variant, it now also reports the number of cases identified and, where available, experimental data supporting the pathogenicity of the variant. The website also provides information on a number of ALD-related topics in several languages. Here, we provide an updated analysis of the known variants in ABCD1. The order of pathogenic variant frequency, overall clustering of disease-causing variants in exons 1–2 (transmembrane domain spanning region) and 6–9 (ATP-binding domain), and the most commonly reported pathogenic variant p.Gln472Argfs*83 in exon 5 are consistent with the initial reports of the mutation database. Novel insights include nonrandom clustering of high-density missense variant hotspots within exons 1, 2, 6, 8, and 9. Perhaps more importantly, we illustrate the importance of collaboration and utility of the database as a scientific, clinical, and ALD-community-wide resource.

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