scholarly journals The Analysis of Variants in the General Population Reveals That PMM2 Is Extremely Tolerant to Missense Mutations and That Diagnosis of PMM2-CDG Can Benefit from the Identification of Modifiers

2018 ◽  
Vol 19 (8) ◽  
pp. 2218 ◽  
Author(s):  
Valentina Citro ◽  
Chiara Cimmaruta ◽  
Maria Monticelli ◽  
Guglielmo Riccio ◽  
Bruno Hay Mele ◽  
...  
Keyword(s):  
General Population ◽  
Autosomal Recessive ◽  
Biochemical Analysis ◽  
Autosomal Recessive Disease ◽  
Type I ◽  
Missense Mutations ◽  
Loss Of Function ◽  
Phenotype Correlation ◽  
Phenotypic Spectrum ◽  
Partial Deficiency

Type I disorders of glycosylation (CDG), the most frequent of which is phosphomannomutase 2 (PMM2-CDG), are a group of diseases causing the incomplete N-glycosylation of proteins. PMM2-CDG is an autosomal recessive disease with a large phenotypic spectrum, and is associated with mutations in the PMM2 gene. The biochemical analysis of mutants does not allow a precise genotype–phenotype correlation for PMM2-CDG. PMM2 is very tolerant to missense and loss of function mutations, suggesting that a partial deficiency of activity might be beneficial under certain circumstances. The patient phenotype might be influenced by variants in other genes associated with the type I disorders of glycosylation in the general population.

scholarly journals ANK3 related neurodevelopmental disorders: expanding the spectrum of heterozygous loss-of-function variants

Neurogenetics ◽  
2021 ◽  
Author(s):  
Katja Kloth ◽  
Bernarda Lozic ◽  
Julia Tagoe ◽  
Mariëtte J. V. Hoffer ◽  
Amelie Van der Ven ◽  
...  
Keyword(s):  
Autosomal Recessive ◽  
Neuronal Development ◽  
Autosomal Dominant ◽  
Tissue Expression ◽  
Autism Spectrum ◽  
Loss Of Function ◽  
Ankyrin G ◽  
Phenotypic Spectrum ◽  
And Function ◽  
Neurodevelopmental Phenotype

AbstractANK3 encodes multiple isoforms of ankyrin-G, resulting in variegated tissue expression and function, especially regarding its role in neuronal development. Based on the zygosity, location, and type, ANK3 variants result in different neurodevelopmental phenotypes. Autism spectrum disorder has been associated with heterozygous missense variants in ANK3, whereas a more severe neurodevelopmental phenotype is caused by isoform-dependent, autosomal-dominant, or autosomal-recessive loss-of-function variants. Here, we present four individuals affected by a variable neurodevelopmental phenotype harboring a heterozygous frameshift or nonsense variant affecting all ANK3 transcripts. Thus, we provide further evidence of an isoform-based phenotypic continuum underlying ANK3-associated pathologies and expand its phenotypic spectrum.

Magnetic resonance imaging findings of adult-onset glutaric aciduria type I

2007 ◽  
Vol 48 (5) ◽  
pp. 557-559 ◽  
Author(s):  
G. Sonmez ◽  
H. Mutlu ◽  
E. Ozturk ◽  
H. O. Sildiroglu ◽  
A. T. Keskin ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Autosomal Recessive ◽  
Autosomal Recessive Disease ◽  
Glutaric Aciduria Type ◽  
Type I ◽  
Imaging Findings ◽  
Resonance Imaging ◽  
Glutaric Aciduria ◽  
Glutaric Acidemia Type I ◽  
Glutaric Aciduria Type I

Glutaric aciduria or glutaric acidemia type I, an autosomal recessive disease, usually presents with an acute encephalopathic crisis in young children. We report the magnetic resonance (MR) and proton MR spectroscopy (MRS) imaging findings of a previously healthy 20-year-old man who presented with recurrent headaches. Organic acids from the patient's urine contained large amounts of adipate, glutarate, and 3-hydroxyglutarate consistent with glutaric aciduria type I.

scholarly journals Sacsin cotranslational degradation causes autosomal recessive spastic ataxia of Charlevoix-Saguenay

2021 ◽  
Author(s):  
Fabiana Longo ◽  
Daniele De Ritis ◽  
Annarita Miluzio ◽  
Davide Fraticelli ◽  
Jonathan Baets ◽  
...  
Keyword(s):  
Autosomal Recessive ◽  
Age Of Onset ◽  
Diagnostic Algorithm ◽  
Disease Diagnosis ◽  
Missense Mutations ◽  
Phenotype Correlation ◽  
Gene Encoding ◽  
Spastic Ataxia ◽  
Protein Reduction ◽  
Compound Heterozygotes

AbstractAutosomal recessive spastic ataxia of Charlevoix-Saguenay is caused by more than 200 different mutations in the SACS gene encoding sacsin, a huge multimodular protein of unknown function. ARSACS phenotypic spectrum is highly variable. Previous studies correlated the nature and position of SACS mutations with age of onset or disease severity, though the effects on protein stability were not considered.In this study, we explain mechanistically the lack of genotype-phenotype correlation in ARSACS, with important consequences for disease diagnosis and treatment.We found that sacsin is almost absent in ARSACS fibroblasts, regardless of the nature of the mutation. We did not detect sacsin in patients with truncating mutations, while we found it strikingly reduced or absent also in compound heterozygotes carrying diverse missense mutations. We excluded SACS mRNA decay, defective translation, or faster post-translational degradation as causes of protein reduction. Conversely, we demonstrated that nascent mutant sacsin protein undergoes preemptive cotranslational degradation, emerging as a novel cause of a human disease. Based on these findings, sacsin levels should be included in the diagnostic algorithm for ARSACS.

scholarly journals A Novel Missense Variant of HOXD13 Caused Atypical Synpolydactyly by Impairing the Downstream Gene Expression and Literature Review for Genotype–Phenotype Correlations

2021 ◽  
Vol 12 ◽  
Author(s):  
Ruiji Guo ◽  
Xia Fang ◽  
Hailei Mao ◽  
Bin Sun ◽  
Jiateng Zhou ◽  
...  
Keyword(s):  
Limb Development ◽  
Missense Variant ◽  
Missense Mutations ◽  
Loss Of Function ◽  
Phenotype Correlation ◽  
Mutation Site ◽  
Genotype Phenotype Correlation ◽  
Α Helix ◽  
Severe Degree ◽  
Hands And Feet

Synpolydactyly (SPD) is a hereditary congenital limb malformation with distinct syndactyly designated as SPD1, SPD2, and SPD3. SPD1 is caused by mutations of HOXD13, which is a homeobox transcription factor crucial for limb development. More than 143 SPD patients have been reported to carry HOXD13 mutations, but there is a lack of genotype–phenotype correlation. We report a novel missense mutation of c. 925A > T (p.I309F) in an individual with atypical synpolydactyly inherited from her father with mild clinodactyly and three other different alanine insertion mutations in HOXD13 identified by whole exome sequencing (WES) in 12 Chinese SPD families. Unlike polyalanine extension, which tends to form α-helix and causes protein aggregation in the cytoplasm as shown by molecular simulation and immunofluorescence, the c. 925A > T mutation impairs downstream transcription of EPHA7. We compiled literature findings and analyzed genotype–phenotype features in 173 SPD individuals of 53 families, including 12 newly identified families. Among the HOXD13-related individuals, mutations were distributed in three regions: polyalanine, homeobox, and non-homeobox. Polyalanine extension was the most common variant (45%), followed by missense mutations (32%) mostly in the homeobox compared with the loss-of-function (LOF) variants more likely in non-homeobox. Furthermore, a more severe degree and classic SPD were associated with polyalanine mutations although missense variants were associated with brachydactyly and syndactyly in hands and feet and LOF variants with clinodactyly in hands. Our study broadens the HOXD13 mutation spectrum and reveals the profile of three different variants and their severity of SPD, the genotype–phenotype correlation related to the HOXD13 mutation site provides clinical insight, including for genetic counseling.

scholarly journals Intracranial Calcifications in Autoimmune Polyendocrine Ectodermal Dystrophy Syndrome (APECED): About A Case Report

2021 ◽  
pp. 1-3
Author(s):  
Benfaddoul O ◽  
◽  
Zouita B ◽  
El azzouzi B ◽  
Basraoui N ◽  
...  
Keyword(s):  
Autosomal Recessive ◽  
Autosomal Recessive Disease ◽  
Chronic Mucocutaneous Candidiasis ◽  
Type I ◽  
Syndrome Type ◽  
Autoimmune Polyglandular Syndrome ◽  
Mucocutaneous Candidiasis ◽  
Autoimmune Polyendocrinopathy ◽  
Life Threatening ◽  
Autoimmune Polyglandular Syndrome Type

Autoimmune polyendocrinopathy ectodermal dystrophy (APECED), also known as autoimmune polyglandular syndrome type I (APS I), is an uncommon, but debilitating autosomal recessive disease caused by mutations in the autoimmune regulator (AIRE), It is characterized by a broad and diverse clinical spectrum which can lead to severe metabolic alterations and eventually life-threatening events. Hypoparathyroidism is one of the major criteria for clinical diagnosis, in addition to chronic mucocutaneous candidiasis and autoimmune adrenal insufficiency. This component is responsible for the forming of brain calcifications which tend to have a characteristic predilection for the basal ganglia. In this article, we report an additional case to the literature and provide a literature review of the expanding radiological spectrum of this syndrome

scholarly journals Mapping Autosomal Recessive Intellectual Disability: Combined Microarray and Exome Sequencing Identifies 26 Novel Candidate Genes in 192 Consanguineous Families

2016 ◽  
Author(s):  
Ricardo Harripaul ◽  
Nasim Vasli ◽  
Anna Mikhailov ◽  
Muhammad Arshad Rafiq ◽  
Kirti Mittal ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Exome Sequencing ◽  
Autosomal Recessive ◽  
De Novo ◽  
Clinical Diagnostics ◽  
High Yield ◽  
Disease Genes ◽  
Missense Mutations ◽  
Loss Of Function ◽  
Whole Exome

Approximately 1% of the global population is affected by intellectual disability (ID), and the majority receive no molecular diagnosis. Previous studies have indicated high levels of genetic heterogeneity, with estimates of more than 2500 autosomal ID genes, the majority of which are autosomal recessive (AR). Here, we combined microarray genotyping, homozygosity-by-descent (HBD) mapping, copy number variation (CNV) analysis, and whole exome sequencing (WES) to identify disease genes/mutations in 192 multiplex Pakistani and Iranian consanguineous families with non-syndromic ID. We identified definite or candidate mutations (or CNVs) in 51% of families in 72 different genes, including 26 not previously reported for ARID. The new ARID genes include nine with loss-of-function mutations(ABI2, MAPK8, MPDZ, PIDD1, SLAIN1, TBC1D23, TRAPPC6B, UBA7,andUSP44),and missense mutations include the first reports of variants inBDNForTET1associated with ID. The genes identified also showed overlap withde novogene sets for other neuropsychiatric disorders. Transcriptional studies showed prominent expression in the prenatal brain. The high yield of AR mutations for ID indicated that this approach has excellent clinical potential and should inform clinical diagnostics, including clinical whole exome and genome sequencing, for populations in which consanguinity is common. As with other AR disorders, the relevance will also apply to outbred populations.

scholarly journals Inborn errors of type I IFN immunity in patients with life-threatening COVID-19

Science ◽  
2020 ◽  
Vol 370 (6515) ◽  
pp. eabd4570 ◽  
Author(s):  
Qian Zhang ◽  
Paul Bastard ◽  
Zhiyong Liu ◽  
Jérémie Le Pen ◽  
Marcela Moncada-Velez ◽  
...  
Keyword(s):  
Autosomal Recessive ◽  
Rare Variants ◽  
Human Fibroblasts ◽  
Severe Infection ◽  
Type I ◽  
Type I Ifn ◽  
Loss Of Function ◽  
Inborn Errors ◽  
Life Threatening ◽  
Dependent Type

Clinical outcome upon infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ranges from silent infection to lethal coronavirus disease 2019 (COVID-19). We have found an enrichment in rare variants predicted to be loss-of-function (LOF) at the 13 human loci known to govern Toll-like receptor 3 (TLR3)– and interferon regulatory factor 7 (IRF7)–dependent type I interferon (IFN) immunity to influenza virus in 659 patients with life-threatening COVID-19 pneumonia relative to 534 subjects with asymptomatic or benign infection. By testing these and other rare variants at these 13 loci, we experimentally defined LOF variants underlying autosomal-recessive or autosomal-dominant deficiencies in 23 patients (3.5%) 17 to 77 years of age. We show that human fibroblasts with mutations affecting this circuit are vulnerable to SARS-CoV-2. Inborn errors of TLR3- and IRF7-dependent type I IFN immunity can underlie life-threatening COVID-19 pneumonia in patients with no prior severe infection.

Congenital Erythropoietic Porphyria: Prenatal Diagnosis and Autopsy Findings in Two Sibling Fetuses

2001 ◽  
Vol 4 (2) ◽  
pp. 180-184 ◽  
Author(s):  
F. Daïkha-Dahmane ◽  
M. Dommergues ◽  
F. Narcy ◽  
M.C. Gubler ◽  
Y. Dumez ◽  
...  
Keyword(s):  
Prenatal Diagnosis ◽  
Amniotic Fluid ◽  
Histological Examination ◽  
Autosomal Recessive ◽  
Dna Analysis ◽  
Autosomal Recessive Disease ◽  
Type I ◽  
Autopsy Findings ◽  
Congenital Erythropoietic Porphyria ◽  
Made In

Congenital erythropoietic porphyria is an autosomal recessive disease characterized by a deficiency of uroporphyrinogen III cosynthetase activity, with diffuse tissue accumulation of specific type I porphyrins. The diagnosis of this disease was made in two fetuses, who were siblings, and from a Caucasian nonconsanguinous family. The first fetus died in utero with hydrops fetalis and anemia, but without an etiopathogenic diagnosis. In the second case, the diagnosis was based on pink fluorescence of the amniotic fluid examined fortuitously in sunlight. DNA analysis showed that the fetus was heteroallelic for the mutation C73R. The autopsy showed brown skin, and at histological examination, porphyrin pigment was deposited in many tissues. Retrospectively, similar deposits were found in the tissues of the first fetus.

scholarly journals The Genetic and Clinical Features of FOXL2-Related Blepharophimosis, Ptosis and Epicanthus Inversus Syndrome

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 364
Author(s):  
Cécile Méjécase ◽  
Chandni Nigam ◽  
Mariya Moosajee ◽  
John C. Bladen
Keyword(s):  
Autosomal Dominant ◽  
Response Assessment ◽  
Type I ◽  
Type Ii ◽  
Loss Of Function ◽  
Phenotype Correlation ◽  
Forkhead Box ◽  
Exact Function ◽  
Craniofacial Features ◽  
Foxl2 Gene

Blepharophimosis, ptosis, and epicanthus inversus syndrome (BPES) is a craniofacial disorder caused by heterozygous variants of the forkhead box L2 (FOXL2) gene. It shows autosomal dominant inheritance but can also occur sporadically. Depending on the mutation, two phenotypic subtypes have been described, both involving the same craniofacial features: type I, which is associated with premature ovarian failure (POF), and type II, which has no systemic features. The genotype–phenotype correlation is not fully understood, but it has been hypothesised that type I BPES involves more severe loss of function variants spanning the whole gene. Type II BPES has been linked to frameshift mutations that result in elongation of the protein rather than complete loss of function. A mutational hotspot has been identified within the poly-alanine domain, although the exact function of this region is still unknown. However, the BPES subtype cannot be determined genetically, necessitating informed genetic counselling and careful discussion of family planning advice in view of the associated POF particularly as the patient may still be a child. Following puberty, female patients should be referred for ovarian reserve and response assessment. Oculofacial features can be managed with surgical intervention and regular monitoring to prevent amblyopia.

scholarly journals Congenital Amegakaryocytic Thrombocytopenia: A Brief Review of the Literature

2010 ◽  
Vol 3 ◽  
pp. CPath.S4972 ◽  
Author(s):  
Fatma S. Al-Qahtani
Keyword(s):  
Bone Marrow ◽  
Autosomal Recessive ◽  
Autosomal Recessive Disorder ◽  
Primary Treatment ◽  
Bleeding Complications ◽  
Type I ◽  
Cell Transplant ◽  
Missense Mutations ◽  
Severe Type ◽  
Marrow Stem Cell

Congenital amegakaryocytic thrombocytopenia (CAMT) is a rare inherited autosomal recessive disorder that presents with thrombocytopenia and absence of megakaryocytes. It presents with bleeding recognized on day 1 of life or at least within the first month. The cause for this disorder appears to be a mutation in the gene for the thrombopoeitin (TPO) receptor, c-Mpl, despite high levels of serum TPO. Patients with severe Type I-CAMT carry nonsense Mpl mutations which causes a complete loss of the TPO receptor whereas those with Type II CAMT carry missense mutations in the Mpl gene affecting the extracellular domain of the TPO receptor. Differential diagnosis for severe CAMT includes thrombocytopenia with absent radii (TAR) and Wiskott-Aldrich syndrome (WAS). The primary treatment for CAMT is bone marrow transplantation. Bone Marrow/Stem Cell Transplant (HSCT) is the only thing that ultimately cures this genetic disease. Newer modalities are on the way, such as TPO-mimetics for binding towards partially functioning c-Mpl receptors and gene therapy. Prognosis of CAMT patients is poor, because all develop in childhood a tri-linear marrow aplasia that is always fatal when untreated. Thirty percent of patients with CAMT die due to bleeding complications and 20% -due to HSCT if it has been done.

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