scholarly journals Mutations Causing Mild or No Structural Damage in Interfaces of Multimerization of the Fibrinogen γ-Module More Likely Confer Negative Dominant Behaviors

2020 ◽  
Vol 21 (23) ◽  
pp. 9016
Author(s):  
Emanuele Bellacchio
Keyword(s):  
Structural Damage ◽  
Autosomal Recessive ◽  
Autosomal Recessive Inheritance ◽  
Molecular Characteristics ◽  
Healthy Population ◽  
Pathogenic Mechanisms ◽  
Recessive Mutations ◽  
Pathogenic Variants ◽  
Variant Frequency ◽  
Disease Inheritance

Different pathogenic variants in the same protein or even within the same domain of a protein may differ in their patterns of disease inheritance, with some of the variants behaving as negative dominant and others as autosomal recessive mutations. Here is presented a structural analysis and comparison of the molecular characteristics of the sites in fibrinogen γ-module, a fibrinogen component critical in multimerization processes, targeted by pathogenic variants (HGMD database) and by variants found in the healthy population (gnomAD database). The main result of this study is the identification of the molecular pathogenic mechanisms defining which pattern of disease inheritance is selected by mutations at the crossroad of autosomal recessive and negative dominant modalities. The observations in this analysis also warn about the possibility that several variants reported in the non-pathogenic gnomAD database might indeed be a hidden source of diseases with autosomal recessive inheritance or requiring a combination with other disease-causing mutations. Disease presentation might remain mostly unrevealed simply because the very low variant frequency rarely results in biallelic pathogenic mutations or the coupling with mutations in other genes contributing to the same disease. The results here presented provide hints for a deeper search of pathogenic mechanisms and modalities of disease inheritance for protein mutants participating in multimerization phenomena.

scholarly journals Spondyloocular Syndrome: A Novel XYLT2 Variant with Description of the Neonatal Phenotype

2021 ◽  
Vol 12 ◽  
Author(s):  
Gabriella Doddato ◽  
Alessandra Fabbiani ◽  
Chiara Fallerini ◽  
Mirella Bruttini ◽  
Theodora Hadjistilianou ◽  
...  
Keyword(s):  
Autosomal Recessive ◽  
Phenotypic Variability ◽  
Autosomal Recessive Inheritance ◽  
Nuchal Translucency ◽  
Gene Encoding ◽  
Nasal Bridge ◽  
Facial Profile ◽  
Pathogenic Variants ◽  
Skeletal Defects ◽  
Bone Abnormalities

Spondyloocular syndrome (SOS) is a skeletal disorder caused by pathogenic variants in XYLT2 gene encoding a xylotransferase involved in the biosynthesis of proteoglycans. This condition, with autosomal recessive inheritance, has a high phenotypic variability. It is characterized by bone abnormalities (osteoporosis, fractures), eye and cardiac defects, hearing impairment, and varying degrees of developmental delay. Until now only 20 mutated individuals have been reported worldwide. Here, we describe two siblings from consanguineous healthy parents in which a novel homozygous frameshift variant c.1586dup p(Thr530Hisfs*) in the XYLT2 gene was detected by exome sequencing (ES). The first patient (9 years) presented short stature with skeletal defects, long face, hearing loss and cataract. The second patient, evaluated at a few days of life, showed macrosomia, diffuse hypertrichosis on the back, overabundant skin in the retronucal area, flattened facial profile with drooping cheeks, elongated eyelid rims, wide and flattened nasal bridge and turned down corners of the mouth. During the prenatal period, high nuchal translucency and intestinal hyperechogenicity were observed at ultrasound. In conclusion, these two siblings with a novel pathogenic variant in XYLT2 further expand the clinical and mutational spectrum of SOS.

scholarly journals Identification of two novel pathogenic variants of PIBF1 by whole exome sequencing in a 2-year-old boy with Joubert syndrome

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Yue Shen ◽  
Hao Wang ◽  
Zhimin Liu ◽  
Minna Luo ◽  
Siyu Ma ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Autosomal Recessive ◽  
Autosomal Recessive Disorder ◽  
Autosomal Recessive Inheritance ◽  
Joubert Syndrome ◽  
Causative Gene ◽  
Pathogenic Variants ◽  
Whole Exome ◽  
Syndrome Individual

Abstract Background Joubert syndrome (OMIM 213300) is an autosomal recessive disorder with gene heterogeneity. Causal genes and their variants have been identified by sequencing or other technologies for Joubert syndrome subtypes. Case presentation A two-year-old boy was diagnosed with Joubert syndrome by global development delay and molar tooth sign of mid-brain. Whole exome sequencing was performed to detect the causative gene variants in this individual, and the candidate pathogenic variants were verified by Sanger sequencing. We identified two pathogenic variants (NM_006346.2: c.1147delC and c.1054A > G) of PIBF1 in this Joubert syndrome individual, which is consistent with the mode of autosomal recessive inheritance. Conclusion In this study, we identified two novel pathogenic variants in PIBF1 in a Joubert syndrome individual using whole exome sequencing, thereby expanding the PIBF1 pathogenic variant spectrum of Joubert syndrome.

Clinical and molecular characteristics and time of diagnosis of patients with classical galactosemia in an unscreened population in Turkey

2019 ◽  
Vol 32 (7) ◽  
pp. 675-681
Author(s):  
Pelin Teke Kisa ◽  
Melis Kose ◽  
Ozlem Unal ◽  
Esra Er ◽  
Burcu Ozturk Hismi ◽  
...  
Keyword(s):  
Newborn Screening ◽  
Autosomal Recessive ◽  
Screening Program ◽  
Clinical Manifestations ◽  
Geographical Location ◽  
Molecular Characteristics ◽  
Phenotype Correlation ◽  
Classical Galactosemia ◽  
Pathogenic Variants ◽  
Turkish Patients

Abstract Classical galactosemia is an autosomal recessive inborn error of metabolism caused by biallelic pathogenic variants in the GALT gene. With the benefit of early diagnosis by newborn screening, the acute presentation of galactosemia can be prevented. In this study, we describe the clinical phenotypes, time of diagnosis and GALT genotypes of 76 galactosemia patients from Turkey, where the disease is not yet included in the newborn screening program. The median age at first symptom was 10 days (range 5–20), while the median age at diagnosis was 30 days (range 17–53). Nearly half of the patients (36 patients, 47.4%) were diagnosed later than age 1 month. Fifty-eight individuals were found to have 18 different pathogenic variants in their 116 mutant alleles. In our sample, Q188R variant has the highest frequency with 53%, the other half of the allele frequency of the patients showed 17 different genotypes. Despite presenting with typical clinical manifestations, classical galactosemia patients are diagnosed late in Turkey. Due to the geographical location of our country, different pathogenic GALT variants may be seen in Turkish patients. In the present study, a clear genotype-phenotype correlation could not be established in patients.

Kohlschütter-Tönz Syndrome With a Novel ROGD1 Variant in 3 Individuals: A Rare Clinical Entity

2021 ◽  
pp. 088307382110047
Author(s):  
Özlem Akgün-Doğan ◽  
Pelin Ozlem Simsek-Kiper ◽  
Ekim Taşkıran ◽  
Anna Schossig ◽  
Gülen Eda Utine ◽  
...  
Keyword(s):  
Autosomal Recessive ◽  
Autosomal Recessive Inheritance ◽  
Epileptic Encephalopathy ◽  
Clinical Findings ◽  
Global Developmental Delay ◽  
Molecular Characteristics ◽  
Long Term Follow Up ◽  
Main Components

Kohlschütter-Tönz syndrome (OMIM 226750) is a rare disorder with autosomal recessive inheritance among epileptic encephalopathy syndromes. To date, only 31 Kohlschütter-Tönz syndrome families have been reported in the literature. Early-onset epilepsy, progressive global developmental delay, and amelogenesis imperfecta are the main components of the syndrome. Mutations in ROGDI (MIM 226750) and SLC13A5 (MIM 615905) are responsible for Kohlschütter-Tönz syndrome. Here, we report on the clinical and molecular characteristics of 3 individuals from 2 families, all harboring the same homozygous novel deleterious variant in ROGD1, along with a long-term follow-up and review of the literature. Although the phenotypic features are almost consistent in Kohlschütter-Tönz syndrome, overlooking dental findings and diverse degrees of variability in clinical findings makes diagnosis challenging occasionally. Because there is a limited number of reported patients, identification of new patients and delineation of clinical and molecular findings will increase the awareness of clinicians and enable establishing genotype-phenotype correlations.

scholarly journals The genetic basis of classical galactosaemia in Polish patients

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Aleksandra Jezela-Stanek ◽  
Anna Bauer ◽  
Katarzyna Wertheim-Tysarowska ◽  
Jerzy Bal ◽  
Agnieszka Magdalena Rygiel ◽  
...  
Keyword(s):  
Autosomal Recessive ◽  
Genetic Basis ◽  
Dna Analysis ◽  
Current Knowledge ◽  
Autosomal Recessive Disorder ◽  
Molecular Characteristics ◽  
Compound Heterozygous ◽  
Classic Galactosemia ◽  
Pathogenic Variants ◽  
Molecular Etiology

AbstractClassic galactosemia (OMIM #230400) is an autosomal recessive disorder caused by homozygous or compound heterozygous pathogenic variants in the galactose-1-phosphate uridylyltransferase gene (GALT; 606999) on chromosome 9p13. Its diagnosis is established by detecting elevated erythrocyte galactose-1-phosphate concentration, reduced erythrocyte galactose-1-phosphate uridylyltransferase (GALT) enzyme activity. Biallelic pathogenic variants in the GALT gene is confirmed by DNA analysis. Our paper presents molecular characteristics of 195 Polish patients diagnosed with galactosemia I, intending to expand the current knowledge of this rare disease's molecular etiology. To the best of our knowledge, the described cohort of galactosemia patients is the largest single-center cohort presented so far.

scholarly journals SLC12A2 mutations cause NKCC1 deficiency with encephalopathy and impaired secretory epithelia

2020 ◽  
Vol 6 (4) ◽  
pp. e478 ◽  
Author(s):  
Tommy Stödberg ◽  
Måns Magnusson ◽  
Nicole Lesko ◽  
Anna Wredenberg ◽  
Daniel Martin Munoz ◽  
...  
Keyword(s):  
Autosomal Recessive ◽  
Neurodevelopmental Disorder ◽  
Brain Mri ◽  
Autosomal Recessive Inheritance ◽  
Recessive Inheritance ◽  
Inheritance Pattern ◽  
Loss Of Function ◽  
Pathogenic Variants ◽  
Gastrointestinal Problems ◽  
Life Threatening

ObjectiveTo describe the phenotype in 2 sisters with a rare constellation of neurologic symptoms and secretory impairments and to identify the etiology by the use of whole-genome sequencing (WGS).MethodsAfter an extensive workup failed to reveal the cause of disease, in a girl with a previously not reported phenotype, WGS of the proband, her diseased older sister, an older healthy brother, and their parents was performed, and potentially pathogenic variants were analyzed.ResultsThe proband and her older sister both presented with neonatal Staphylococcus aureus parotitis, apneas, disappearance of the Moro reflex, and hypotonia. The proband survived. Her brain MRI showed white matter and basal ganglia abnormalities, and CSF damage biomarkers were increased. At age 8 years, she exhibits a constellation of symptoms including severe neurodevelopmental disorder, hearing impairment, gastrointestinal problems, and a striking lack of tear fluid, saliva, and sweat. Her respiratory mucosa is dry with potentially life-threatening mucus plugging. Through WGS, 2 loss-of-function variants in SLC12A2 were identified that follow an autosomal recessive inheritance pattern.ConclusionsTaken together with a single previously reported case and the close resemblance to the phenotypes of corresponding mouse models, our study firmly establishes biallelic variants in SLC12A2 as causing human disease and adds data regarding the neurologic phenotype.

scholarly journals Recessive genetic effects on type 2 diabetes-related metabolites in a consanguineous population

2019 ◽  
Author(s):  
Ayşe Demirkan ◽  
Jun Liu ◽  
Najaf Amin ◽  
Jan B van Klinken ◽  
Ko Willems van Dijk ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Autosomal Recessive ◽  
Metabolic Diseases ◽  
Genetic Model ◽  
Autosomal Recessive Inheritance ◽  
P Value ◽  
Recessive Mutations ◽  
Nominal Significance ◽  
The Central Nervous System

AbstractAutozygosity, meaning inheritance of an ancestral allele in the homozygous state is known to lead bi-allelic mutations that manifest their effects through the autosomal recessive inheritance pattern. Autosomal recessive mutations are known to be the underlying cause of several Mendelian metabolic diseases, especially among the offspring of related individuals. In line with this, inbreeding coefficient of an individual as a measure of cryptic autozygosity among the general population is known to lead adverse metabolic outcomes including Type 2 diabetes (T2DM); a multifactorial metabolic disease for which the recessive genetic causes remain unknown. In order to unravel such effects for multiple metabolic facades of the disease, we investigated the relationship between the excess of homozygosity and the metabolic signature of T2DM. We included a set of 53 metabolic phenotypes, including 47 metabolites, T2DM and five T2DM risk factors, measured in a Dutch genetic isolate of 2,580 people. For 20 of these markers, we identified 29 regions of homozygous (ROHs) associated with the nominal significance of P-value < 1.0 × 10−3. By performing association according to the recessive genetic model within these selected regions, we identified and replicated two intronic variants: rs6759814 located in KCNH7 associated with valine and rs1573707 located in PTPRT associated with IDL-free cholesterol and IDL-phospholipids. Additionally, we identified a rare intronic SNV in TBR1 for which the homozygous individuals were enriched for obesity. Interestingly, all three genes are mainly neuronally expressed and pointed out the involvement of glutamergic synaptic transmission pathways in the regulation of metabolic pathways. Taken together our study underline the additional benefits of model supervised analysis, but also seconds the involvement of the central nervous system in T2DM and obesity pathogenesis.

scholarly journals Effect of inbreeding on type 2 diabetes-related metabolites in a Dutch genetic isolate

2019 ◽  
Author(s):  
Ayşe Demirkan ◽  
Jun Liu ◽  
Najaf Amin ◽  
Ko Willems van Dijk ◽  
Cornelia M. van Duijn
Keyword(s):  
Risk Factors ◽  
Type 2 Diabetes ◽  
Autosomal Recessive ◽  
Metabolic Diseases ◽  
Additive Model ◽  
Autosomal Recessive Inheritance ◽  
Genetic Isolate ◽  
Remarkable Effect ◽  
Recessive Mutations

AbstractAutozygosity, meaning inheritance of an ancestral allele in the homozygous state is known to lead bi-allelic mutations that manifest their effects through the autosomal recessive inheritance pattern. Autosomal recessive mutations are known to be the underlying cause of several Mendelian metabolic diseases, especially among the offspring of related individuals. In line with this, inbreeding coefficient of an individual as a measure of cryptic autozygosity among the general population is known to lead adverse metabolic outcomes including type 2 diabetes (T2DM), a multifactorial metabolic disease for which the recessive genetic causes remain unknown. In order to unravel such effects for multiple metabolic facades of the disease, we investigated the relationship between the excess of homozygosity and the metabolic signature of T2DM. We included a set of heritable 143 circulating markers associated with fasting glucose in a Dutch genetic isolate Erasmus Rucphen Family (ERF) of up to 2,580 individuals. We calculated individual whole genome-based, exome-based and pedigree-based inbreeding coefficients and tested their influence on the T2DM-related metabolites as well as T2DM risk factors. We also performed model supervised genome-wide association analysis (GWAS) for the metabolites which significantly correlate with inbreeding values. Inbreeding value of the population significantly and positively correlated with associated with risk factors of T2DM: body-mass index (BMI), glucose, insulin resistance, fasting insulin and waist-hip ratio. We found that inbreeding influenced 32.9% of the T2DM-related metabolites, clustering among chemical groups of lipoproteins, amino-acids and phosphatidylcholines, whereas 80 % of these significant associations were independent of the BMI. The most remarkable effect of inbreeding is observed for S-HDL-ApoA1, for which we show evidence of the novel DISP1 genetic region discovered by model supervised GWAS, in the ERF population. In conclusion, we show that inbreeding effects human metabolism and genetic models other than the globally used additive model is worth considering for study of metabolic phenotypes.

scholarly journals A Compound Heterozygous Mutation in the Ciliary Gene TTC21B Causes Nephronophthisis Type 12

2019 ◽  
Vol 09 (03) ◽  
pp. 198-202
Author(s):  
Wafaa Moustafa M. Abo El Fotoh ◽  
Amira Fathy Al-fiky
Keyword(s):  
Autosomal Recessive ◽  
Autosomal Recessive Inheritance ◽  
Compound Heterozygous Mutation ◽  
Heterozygous Mutation ◽  
Compound Heterozygous ◽  
Renal Disorder ◽  
Pathogenic Variants ◽  
Tubulointerstitial Lesions ◽  
Stage Renal Disease ◽  
End Stage

AbstractNephronophthisis (NPHP) is one of the renal ciliopathies and is also a cystic renal disorder with an autosomal recessive inheritance, which usually progresses to end-stage renal disease (ESRD). It affects children, adolescents, and young adults. In approximately 15% of cases, the features of a ciliopathy syndrome, which include liver fibrosis, skeletal anomalies, retinal abnormalities, and neurodevelopmental delay, will be present. We describe a case of a 2-year-old male child with ESRD on hemodialysis and a family record of a similar condition (his brother). The clinical features of this child are succinctly summarized. The genetic study was conducted using whole exome sequencing. TTC21B mutational variants were detected in our patient who exhibited nephrotic-range proteinuria, focal segmental glomerulosclerosis, and tubulointerstitial lesions that evolved to ESRD. Compound heterozygous mutations, c.626c > t (p.P209L) in exon 6 and c.450 g > a (p.W150Ter) in exon 5, were uncovered. These findings are in line with the description of autosomal recessive NPHP type 12. Both clinical and pathological diagnoses of NPHP are critical, bearing in mind ESRD as well as its related extrarenal defining features. Identification of the pathogenic variants in the TTC21B gene assisted in the successful proof of the clinical diagnosis NPHP12 as well as providing information for formal suitable prenatal counseling.

scholarly journals Novel Autosomal Recessive Splice-Altering Variant in PRKD1 Is Associated with Congenital Heart Disease

Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 612
Author(s):  
Salam Massadeh ◽  
Maha Albeladi ◽  
Nour Albesher ◽  
Fahad Alhabshan ◽  
Kapil Dev Kampe ◽  
...  
Keyword(s):  
Congenital Heart ◽  
Autosomal Recessive ◽  
Heart Defects ◽  
Pulmonary Stenosis ◽  
Autosomal Recessive Inheritance ◽  
Calcium Calmodulin Dependent ◽  
Recessive Mutations ◽  
Whole Exome ◽  
Dependent Protein ◽  
Inheritance Mode

Congenital heart defects (CHDs) are the most common types of birth defects, and global incidence of CHDs is on the rise. Despite the prevalence of CHDs, the genetic determinants of the defects are still in the process of being identified. Herein, we report a consanguineous Saudi family with three CHD affected daughters. We used whole exome sequencing (WES) to investigate the genetic cause of CHDs in the affected daughters. We found that all affected individuals were homozygous for a novel splice-altering variant (NM_001330069.1: c.265-1G>T) of PRKD1, which encodes a calcium/calmodulin-dependent protein kinase in the heart. The homozygous variant was found in the affected patients with Pulmonary Stenosis (PS), Truncus Arteriosis (TA), and Atrial Septal Defect (ASD). Based on the family’s pedigree, the variant acts in an autosomal recessive manner, which makes it the second autosomal recessive variant of PRKD1 to be identified with a link to CHDs, while all other previously described variants act dominantly. Interestingly, the father of the affected daughters was also homozygous for the variant, though he was asymptomatic of CHDs himself. Since both of his sisters had CHDs as well, this raises the possibility that the novel PRKD1 variant may undergo autosomal recessive inheritance mode with gender limitation. This finding confirms that CHD can be associated with both dominant and recessive mutations of the PRKD1 gene, and it provides a new insight to genotype–phenotype association between PRKD1 and CHDs. To our knowledge, this is the first report of this specific PRKD1 mutation associated with CHDs.

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