scholarly journals A Novel GDAP1 Mutation 439delA is Associated with Autosomal Recessive CMT Disease

Author(s):  
Domna-Maria Georgiou ◽  
Paschalis Nicolaou ◽  
David Chitayat ◽  
Pantelitsa Koutsou ◽  
Riyana Babul-Hirji ◽  
...  

Background:Charcot-Marie-Tooth (CMT) disease is the most common form of inherited motor and sensory neuropathy. Based on neurophysiological and neuropathological criteria CMT has been sub-classified into two main types: demyelinating and axonal. Furthermore, it is genetically heterogeneous with autosomal dominant, autosomal recessive (AR) and X-linked modes of inheritance. Thus far, seven genes have been identified in association with the demyelinating AR-CMT disease. We hereby report our clinical and molecular genetic findings in a consanguineous family with AR-CMT.Methods:Two young sisters with AR-CMT and other non-affected family members were clinically and electrophysiologically evaluated and then molecular genetic investigation was carried out in order to identify the pathogenic mutation.Results:Following an initial indication for linkage of the family to the CMT4A locus on chromosome 8, we sequenced the Ganglioside-induced differentiation-associated protein 1 (GDAP1) gene and identified a single nucleotide deletion in exon 3 that is associated with AR-CMT in the family.Conclusion:We identified a novel GDAP1 439delA mutation that is associated with AR-CMT in a consanguineous family of Iranian descent with two affected young girls and a history in other members of the family.

2019 ◽  
Vol 09 (02) ◽  
pp. 117-120
Author(s):  
Pavalan Selvam ◽  
Shekhar Singh ◽  
Angita Jain ◽  
Herjot Atwal ◽  
Paldeep S. Atwal

AbstractOtospondylomegaepiphyseal dysplasia (OSMED) is an inherited autosomal dominant and recessive skeletal dysplasia caused by both heterozygous and homozygous pathogenic variants in COL11A2 encoding the α2(XI) collagen chains, a part of type XI collagen. Here, we describe a 2-year-old girl presenting from birth with a phenotype suggestive of OSMED. On whole exome sequence analysis of the family via commercially available methods, we detected two novel heterozygous pathogenic variants in the proband. In addition, we reviewed the phenotype of autosomal recessive OSMED cases with COL11A2 pathogenic variants reported to date and quantitatively highlighted the phenotypic spectrum.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1675-1675
Author(s):  
Hong-Yan Du ◽  
Elena Pumbo ◽  
Peter Manley ◽  
David B. Wilson ◽  
Philip Mason ◽  
...  

Abstract Dyskeratosis congenita (DC) is a rare inherited bone marrow failure syndrome. Classically, DC presents with progressive bone marrow failure, abnormal skin pigmentation, nail dystrophy, and mucosal leukoplakia. The pattern of inheritance in families with DC suggests an X-linked recessive, an autosomal dominant, and an autosomal recessive form of DC. However, in the majority of patients the occurrence of the disease is sporadic or the family history is unknown. Mutations in four different genes have been associated with DC so far. Mutations in DKC1 have been shown to account for the X-linked form of DC and DKC1 de novo mutations account for about one third of male patients with sporadic disease. Mutations in the telomerase RNA TERC and in the catalytic subunit of telomerase, TERT, have been shown to be responsible for the autosomal dominant form of DC. Interestingly, patients with heterozygous mutations in TERC and TERT often show a milder form of disease and a later age of onset and often lack the classic mucocutaeous features, thus are classified as atypical DC. Very recently homozygosity for a mutation in NOP10 has been identified in one family with autosomal recessive disease. The products of the genes mutated in DC are all components of the telomerase complex, suggesting that disease in patients with DC is caused by a defect in telomere maintenance. Here we investigated two patients, one UPN # 199.001 presenting with the classic manifestations of DC and the other UPN# 284.001 presenting with progressive bone marrow failure but no other clinical features suggestive of DC. In both patients the telomeres measured in peripheral blood mononuclear cells were very short, being defined as being below the 1st percentile. Mutation analysis in the genes associated with DC revealed that patient 199.001 was homozygous for a novel TERT (C2110T) gene mutation, causing an amino acid change (P704S) within the RT domain of TERT. Both parents were heterozygous for the C to T transition. Interestingly however, the father was in addition heterozygote for a second mutation in TERT (C1234T; H412Y) a mutation which has previously been described and has been shown to reduce telomerase activity by 50%. Investigations of the family revealed that the parent’s were distantly related, explaining the same TERT sequence alteration in both parents. Both arms of the family contained members with pulmonary fibrosis. In the second patient 284.001 we identified two different novel TERT gene mutations. One A2537G causes the amino acid change Y846C in the RT domain of TERT whereas the other C2628G causes H876Q also in the RT domain. One of the mutations was inherited from each parent and the parent with the A2537G mutation also had very short telomeres. These two families illustrate that the pattern of inheritance in patients with DC may be complex and show for the first time that homozygous or compound heterozygous TERT gene mutation may be associated with DC. Co-dominance of the three different TERT gene mutations and the inheritance of short telomeres have possibly contributed to development of disease in these patients who were thought to have sporadic DC and idiopathic aplastic anemia.


F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 666
Author(s):  
Jamie Willows ◽  
Maryam Al Badi ◽  
Chloe Richardson ◽  
Noel Edwards ◽  
Sarah Rice ◽  
...  

Genetic mutations causing familial hypomagnesaemia syndromes are well-recognised.  Affected patients can present with severe symptoms of hypomagnesaemia, such as seizures or cardiac arrhythmia.  We report an affected child, from a consanguineous family, who presented in the first weeks of life with seizures secondary to hypomagnesaemia, without other associated clinical features.  We performed whole exome sequencing in the affected child and segregation analysis within the family, which revealed a novel homozygous missense mutation in TRPM6, which was confirmed as a heterozygous allele in both parents and two younger siblings who had transient hypomagnesaemia. Using in silico modelling, we provide evidence that the missense variant p.(K1098E) in TRPM6 is pathogenic, as it disrupts stabilising TRP domain interactions. Management of familial hypomagnesaemia relies on prompt recognition, early magnesium replacement and lifelong monitoring.


2015 ◽  
Vol 19 (6) ◽  
pp. 595-599 ◽  
Author(s):  
Najla Al-Dawsari ◽  
Ahmed Al-Mokhadam ◽  
Hind Al-Abdulwahed ◽  
Nouriya Al-Sannaa

Background: Nail-patella syndrome (NPS) is an autosomal dominant disorder with a variable interfamilial and intrafamilial clinical expressivity and penetrance. It is caused by loss-of-function heterozygous mutation in the LIM-homeodomain transcription factor (LMX1B) located on chromosome 9q. The pleiotropic LMB1X gene, a member of the homeogene family, is involved in the development of glomerular basement membrane, dorsoventral limb structures, along with the nails and the anterior segment of the eye. Objective: Here, we report a Saudi Arab consanguineous family with 2 affected sisters presented with the typical nail changes of NPS. Methods: DNA samples were collected from the sisters and their parents after consent. Results: Both sisters were found to be homozygous for a previously described disease-causing mutation (c.268C>T) at the (LMX1B) gene. Both of the phenotypically normal parents were confirmed to be heterozygous for the same mutation. Conclusion: This finding supports the autosomal recessive mode of inheritance in this family.


1995 ◽  
Vol 112 (5) ◽  
pp. P102-P102
Author(s):  
Richard J.H. Smith ◽  
Kenneth M. Grundfast

Educational objectives: To understand the types of hereditary hearing impairment (autosomal dominant, autosomal recessive, X-linked, mitochondrial, syndromic, nonsyndromic) and the importance of clinical diagnosis in molecular genetic studies of hereditary hearing impairment.


2021 ◽  
Vol 17 (3) ◽  
pp. 93-97
Author(s):  
I.V. Lastivka ◽  
V.V. Antsupva ◽  
A.H. Babintseva ◽  
M.D. Unhurian ◽  
I.A. Ushko

Relevance. Kabuki Makeup Syndrome (KS) is a rare monogenic genetic disease characterized by multiple malformations. The phenotype includes specific facial features, skeletal and dermatoglyphic abnormalities, mental retardation, short stature. Most cases are associated with de novo mutations in the KMT2D and KMD6A genes. However, in 25% of patients with KS, the genetic basis remains unknown, which indicates the genetic heterogeneity of the disease and encourages further accumulation of clinical experience in KS. The article summarizes current data on the molecular geneticі aspects of the development of Kabuki Makeup Syndrome and describes its own clinical case of Kabuki Makeup Syndrome Type I. Objective: to summarize the data on modern molecular-genetic aspects of the development of Kabuki makeup syndrome on the example of a clinical case. Materials and methods. Analysis of scientific publications in the international electronic scientometric database Scopus, PubMed by keywords. Search depth – 15 years (2007-2021). The clinical case of Kabuki Makeup Syndrome from our own practice. Clinical and genealogical, molecular-genetic, cytogenetic, instrumental research methods. Results. According to current data, the development of Kabuki Makeup Syndrome is due to mutations in the KMT2D (MLL2) gene, which belongs to the genes that control embryogenesis. KMT2D functions as a promoter of the expression of other genes and the KDM6A gene; encodes a large multidomain protein that interacts with the SET1/COMPASS complex. KDM6A is a cofactor physically associated with the KMT2D-COMPASS complex and exhibits demethylase activity in histone 3. Gene mutations KMT2D and KDM6A associated with KS lead to a lack of functioning of the corresponding enzyme, which leads to impaired methylation of histones and active genes in many organs and tissues of the body. Depending on the type of mutation in the KMT2D and KMD6A genes, there are two types of Kabuki Makeup Syndrome. KS type 1 with autosomal dominant type of inheritance due to pathogenic mutations in the KMT2D gene in a heterozygous state on chromosome 12q13.12. 70% of patients have KS1. Type 2 KS is an X-linked disease that develops as a result of a heterozygous pathogenic mutation in the KDM6 gene. In most cases, KS mutations are sporadic, but families with parent-to-child transmission have been described. In patients with phenotypic signs of KS pathogenic mutations are detected in 75% of cases. Pathogenic mutations in the KMT2D gene can be detected in mosaic form, and the carrier can pass this mutation on to offspring. Pathogenic mutations have not been described in phenotypically healthy people. Here is our own observation. The girl with a combined congenital heart defect and multiple stigmas of dysembryogenesis was born at 36 weeks with a weight of 2930, 49 cm long, on the Apgar scale 8/8 points from the third planned pregnancy in parents who already had an older healthy boy. In connection with multiple malformations, the girl underwent a syndromic diagnosis using the program "Face2gene"; Kabuki Makeup Syndrome is suspected. Molecular genetic analysis revealed a pathogenic mutation (c.11884C>T) (p.Gln3962*) in the KMT2D gene, which is associated with autosomal dominant Kabuki Makeup Syndrome of type 1 (MedGen UID: 893727). Conclusions. Kabuki Makeup Syndrome has clinical and molecular polymorphisms. Most of the registered KMT2D mutations occur de novo and occur in episodic cases. The described case demonstrates the molecular-positive Kabuki Makeup Syndrome of type I. The identified variant c.11884C>T(p.Gln3962*) in the KMT2D gene is associated with the autosomal dominant Kabuki Makeup Syndrome (MedGen UID: 893727). Verification of the diagnosis of the disease and prevention of KS in siblings is based on the results of molecular genetic analysis. The prognosis of this disease depends on the severity of heart disease and intellectual impairment. Early diagnosis determines the type and timing of therapeutic interventions, is crucial for medical and genetic counseling of the family.


2017 ◽  
Vol 6 (1) ◽  
Author(s):  
Satyaranjan Pegu ◽  
Jaya. P. Bodani ◽  
Edmond G. Lemire ◽  
Karen I. Holfeld

Abstract Epidermolytic hyperkeratosis (EHK) is a rare skin condition characterized by erythroderma and blistering at birth, leading to generalized hyperkeratosis of varying severity in adulthood. EHK is frequently mistaken for staphylococcal scalded skin syndrome (SSSS) or epidermolysis bullosa. EHK is usually inherited in an autosomal dominant fashion, but very rare autosomal recessive families have been reported. Molecular genetic testing in this patient identified a novel homozygous keratin-10 gene (KRT10) mutation consistent with autosomal recessive inheritance. Furthermore, diagnosis was achieved by molecular genetic testing circumventing the need to perform a skin biopsy.


F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 666
Author(s):  
Jamie Willows ◽  
Maryam Al Badi ◽  
Chloe Richardson ◽  
Aisha Al Sinani ◽  
Noel Edwards ◽  
...  

Genetic mutations causing familial hypomagnesaemia syndromes are well-recognised.  Affected patients can present with severe symptoms of hypomagnesaemia, such as seizures or cardiac arrhythmia.  We report an affected child, from a consanguineous family, who presented in the first weeks of life with seizures secondary to hypomagnesaemia, without other associated clinical features.  We performed whole exome sequencing in the affected child and segregation analysis within the family, which revealed a novel homozygous missense mutation in TRPM6, which was confirmed as a heterozygous allele in both parents and two younger siblings who had transient hypomagnesaemia. Using in silico modelling, we provide evidence that the missense variant p.(K1098E) in TRPM6 is pathogenic, as it disrupts stabilising TRP domain interactions. Management of familial hypomagnesaemia relies on prompt recognition, early magnesium replacement and lifelong monitoring.


2021 ◽  
Vol 24 (10) ◽  
pp. 747-751
Author(s):  
Sara Cheraghi ◽  
Sahar Moghbelinejad ◽  
Hossein Najmabadi ◽  
Kimia Kahrizi ◽  
Reza Najafipour

Background: Intellectual disability (ID) is a heterogonous disorder with complex etiology. The frequency of autosomal recessive inheritance defects was elevated in a consanguineous family. Methods: In this study, high-throughput DNA sequencing was performed in an Iranian consanguineous family with two affected individuals to find potential causative variants. Whole-exome sequencing was carried out on the proband and Sanger sequencing was implemented for validation of the likely causative variant in the family members. Results: A novel homozygous missense mutation (p.Arg122Trp) was detected in the PTRHD1 gene. Conclusion: PTRHD1 has been recently introduced as a candidate ID and Parkinsonism causing gene. Our findings are in agreement with the clinical spectrum of PTRHD1 mutations; however, our affected individuals suffer from ID manifestations.


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