scholarly journals Partial Lipodystrophy and LMNA p.R545H Variant

2021 ◽  
Vol 10 (5) ◽  
pp. 1142
Author(s):  
Silvia Magno ◽  
Giovanni Ceccarini ◽  
Andrea Barison ◽  
Iacopo Fabiani ◽  
Alessandro Giacomina ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Subcutaneous Fat ◽  
Gene Mutations ◽  
In Silico Analysis ◽  
Missense Variant ◽  
Fat Distribution ◽  
Incomplete Penetrance ◽  
Partial Lipodystrophy ◽  
Variable Expressivity ◽  
Organ Systems

Laminopathies are disorders caused by LMNA gene mutations, which selectively affect different tissues and organ systems, and present with heterogeneous clinical and pathological traits. The molecular mechanisms behind these clinical differences and tissue specificity have not been fully clarified. We herein examine the case of a patient carrying a heterozygous LMNA c.1634G>A (p.R545H) variant with a mild, transient myopathy, who was referred to our center for the suspicion of lipodystrophy. At physical examination, an abnormal distribution of subcutaneous fat was noticed, with fat accumulation in the anterior regions of the neck, resembling the fat distribution pattern of familial partial lipodystrophy type 2 (FPLD2). The R545H missense variant has been found at very low allelic frequency in public databases, and in silico analysis showed that this amino acid substitution is predicted to have a damaging role. Other patients carrying the heterozygous LMNA p.R545H allele have shown a marked clinical heterogeneity in terms of phenotypic body fat distribution and severity of organ system involvement. These findings indicate that the LMNA p.R545H heterozygous variant exhibits incomplete penetrance and highly variable expressivity. We hypothesized that additional genetic factors, epigenetic mechanisms, or environmental triggers might explain the variable expressivity of phenotypes among various patients.

A genome-wide linkage scan for familial partial lipodystrophy susceptibility genes in a German kindreds

2007 ◽  
Vol 30 (4) ◽  
pp. 86
Author(s):  
M. Lanktree ◽  
J. Robinson ◽  
J. Creider ◽  
H. Cao ◽  
D. Carter ◽  
...  
Keyword(s):  
Subcutaneous Fat ◽  
Visceral Obesity ◽  
Fat Distribution ◽  
Dominant Negative ◽  
Molecular Forms ◽  
Partial Lipodystrophy ◽  
Genome Wide ◽  
A Genome ◽  
Familial Partial Lipodystrophy ◽  
Promoter Mutations

Background: In Dunnigan-type familial partial lipodystrophy (FPLD) patients are born with normal fat distribution, but subcutaneous fat from extremities and gluteal regions are lost during puberty. The abnormal fat distribution leads to the development of metabolic syndrome (MetS), a cluster of phenotypes including hyperglycemia, dyslipidemia, hypertension, and visceral obesity. The study of FPLD as a monogenic model of MetS may uncover genetic risk factors of the common MetS which affects ~30% of adult North Americans. Two molecular forms of FPLD have been identified including FPLD2, resulting from heterozygous mutations in the LMNA gene, and FPLD3, resulting from both heterozygous dominant negative and haploinsufficiency mutations in the PPARG gene. However, many patients with clinically diagnosed FPLD have no mutation in either LMNA or PPARG, suggesting the involvement of additional genes in FPLD etiology. Methods: Here, we report the results of an Affymetrix 10K GeneChip microarray genome-wide linkage analysis study of a German kindred displaying the FPLD phenotype and no known lipodystrophy-causing mutations. Results: The investigation identified three chromosomal loci, namely 1q, 3p, and 9q, with non-parametric logarithm of odds (NPL) scores >2.7. While not meeting the criteria for genome-wide significance, it is interesting to note that the 1q and 3p peaks contain the LMNA and PPARG genes respectively. Conclusions: Three possible conclusions can be drawn from these results: 1) the peaks identified are spurious findings, 2) additional genes physically close to LMNA, PPARG, or within 9q, are involved in FPLD etiology, or 3) alternative disease causing mechanisms not identified by standard exon sequencing approaches, such as promoter mutations, alternative splicing, or epigenetics, are also responsible for FPLD.

scholarly journals Congenital Hyperinsulinism Due to a Novel Activating Glucokinase Mutation: A Case Report and Literature Review

2020 ◽  
Vol 5 (6) ◽  
Keyword(s):  
Case Report ◽  
Novel Mutation ◽  
Gene Mutations ◽  
In Silico Analysis ◽  
Missense Variant ◽  
Laboratory Evaluation ◽  
Congenital Hyperinsulinism ◽  
Hypoglycemic Episode ◽  
Glucokinase Mutation ◽  
Uncertain Significance

Background: Congenital Hyperinsulinism (CHI) constitutes a major cause of persistent and recurrent hypoglycemia, especially in the neonatal period, showing notable phenotypical heterogeneity among affected subjects. Activating mutations of the Glucokinase gene (GCK) are responsible for mild forms of hypoglycemia, due to CHI, usually easily medically managed. Case report: We present a patient at the age of 3.5 years old investigated for persistent hypoglycemia. Laboratory evaluation showed hyperinsulinism during the hypoglycemic episode with a required glucose infusion rate greater than 8-10 mg/kg/min to maintain normoglycemia. Targeted gene panel sequencing revealed an activating missense novel mutation p.Val71Ala in exon 3 of GCK gene, dominantly inherited by his mother. In silico, analysis of this novel missense variant assessed its pathogenicity as being of uncertain significance Conclusions: GCK gene mutations result in varying phenotypic characteristics and responsiveness to diazoxide depending on the type of activating mutation.

Autosomal recessive congenital hereditary corneal dystrophy associated with a novel SLC4A11 mutation in two consanguineous Tunisian families

2021 ◽  
pp. bjophthalmol-2020-318204
Author(s):  
Zohra Chibani ◽  
Imen Zone Abid ◽  
Peter Söderkvist ◽  
Jamel Feki ◽  
Mounira Hmani Aifa
Keyword(s):  
Autosomal Recessive ◽  
Corneal Transplantation ◽  
Gene Mutations ◽  
In Silico Analysis ◽  
Corneal Dystrophy ◽  
Solute Carrier Family ◽  
Transporter Protein ◽  
Bicarbonate Transporter ◽  
Corneal Clouding ◽  
Solute Carrier

BackgroundAutosomal recessive congenital hereditary corneal dystrophy (CHED) is a rare isolated developmental anomaly of the eye characterised by diffuse bilateral corneal clouding that may lead to visual impairment requiring corneal transplantation. CHED is known to be caused by mutations in the solute carrier family 4 member 11 (SLC4A11) gene which encodes a membrane transporter protein (sodium bicarbonate transporter-like solute carrier family 4 member 11).MethodsTo identify SLC4A11 gene mutations associated with CHED (OMIM: #217700), genomic DNA was extracted from whole blood and sequenced for all exons and intron-exon boundaries in two large Tunisian families.ResultsA novel deletion SLC4A11 mutation (p. Leu479del; c.1434_1436del) is responsible for CHED in both analysed families. This non-frameshift mutation was found in a homozygous state in affected members and heterozygous in non-affected members. In silico analysis largely support the pathogenicity of this alteration that may leads to stromal oedema by disrupting the osmolarity balance. Being localised to a region of alpha-helical secondary structure, Leu479 deletion may induce protein-compromising structural rearrangements.ConclusionTo the best of our knowledge, this is the first clinical and genetic study exploring CHED in Tunisia. The present work also expands the list of pathogenic genotypes in SLC4A11 gene and its associated clinical diagnosis giving more insights into genotype–phenotype correlations.

scholarly journals DNA methylation epi-signature is associated with two molecularly and phenotypically distinct clinical subtypes of Phelan-McDermid syndrome

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
L. C. Schenkel ◽  
E. Aref-Eshghi ◽  
K. Rooney ◽  
J. Kerkhof ◽  
M. A. Levy ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Critical Region ◽  
Deletion Syndrome ◽  
Genetic Defects ◽  
Chromosome 22 ◽  
Incomplete Penetrance ◽  
Variable Size ◽  
Variable Expressivity ◽  
Genome Wide ◽  
22Q13.3 Deletion Syndrome

Abstract Background Phelan-McDermid syndrome is characterized by a range of neurodevelopmental phenotypes with incomplete penetrance and variable expressivity. It is caused by a variable size and breakpoint microdeletions in the distal long arm of chromosome 22, referred to as 22q13.3 deletion syndrome, including the SHANK3 gene. Genetic defects in a growing number of neurodevelopmental genes have been shown to cause genome-wide disruptions in epigenomic profiles referred to as epi-signatures in affected individuals. Results In this study we assessed genome-wide DNA methylation profiles in a cohort of 22 individuals with Phelan-McDermid syndrome, including 11 individuals with large (2 to 5.8 Mb) 22q13.3 deletions, 10 with small deletions (< 1 Mb) or intragenic variants in SHANK3 and one mosaic case. We describe a novel genome-wide DNA methylation epi-signature in a subset of individuals with Phelan-McDermid syndrome. Conclusion We identified the critical region including the BRD1 gene as responsible for the Phelan-McDermid syndrome epi-signature. Metabolomic profiles of individuals with the DNA methylation epi-signature showed significantly different metabolomic profiles indicating evidence of two molecularly and phenotypically distinct clinical subtypes of Phelan-McDermid syndrome.

scholarly journals Allelic Variants in Established Hypopituitarism Genes Expand Our Knowledge of the Phenotypic Spectrum

Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1128
Author(s):  
Marilena Nakaguma ◽  
Nathalia Garcia Bianchi Pereira Ferreira ◽  
Anna Flavia Figueredo Benedetti ◽  
Mariana Cotarelli Madi ◽  
Juliana Moreira Silva ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Male Patient ◽  
Missense Variant ◽  
Hormone Deficiency ◽  
Pituitary Hormone ◽  
Incomplete Penetrance ◽  
Growth Hormone Gene ◽  
Posterior Lobe ◽  
Allelic Variants ◽  
Phenotypic Spectrum

We report four allelic variants (three novel) in three genes previously established as causal for hypopituitarism or related disorders. A novel homozygous variant in the growth hormone gene, GH1 c.171delT (p.Phe 57Leufs*43), was found in a male patient with severe isolated growth hormone deficiency (IGHD) born to consanguineous parents. A hemizygous SOX3 allelic variant (p.Met304Ile) was found in a male patient with IGHD and hypoplastic anterior pituitary. YASARA, a tool to evaluate protein stability, suggests that p.Met304Ile destabilizes the SOX3 protein (ΔΔG = 2.49 kcal/mol). A rare, heterozygous missense variant in the TALE homeobox protein gene, TGIF1 (c.268C>T:p.Arg90Cys) was found in a patient with combined pituitary hormone deficiency (CPHD), diabetes insipidus, and syndromic features of holoprosencephaly (HPE). This variant was previously reported in a patient with severe holoprosencephaly and shown to affect TGIF1 function. A novel heterozygous TGIF1 variant (c.82T>C:p.Ser28Pro) was identified in a patient with CPHD, pituitary aplasia and ectopic posterior lobe. Both TGIF1 variants have an autosomal dominant pattern of inheritance with incomplete penetrance. In conclusion, we have found allelic variants in three genes in hypopituitarism patients. We discuss these variants and associated patient phenotypes in relation to previously reported variants in these genes, expanding our knowledge of the phenotypic spectrum in patient populations.

scholarly journals EFFECTS OF BREED AND SEX ON THE PATTERNS OF FAT DEPOSITION AND DISTRIBUTION IN SWINE

1980 ◽  
Vol 60 (2) ◽  
pp. 223-230 ◽  
Author(s):  
S. D. M. JONES ◽  
R. J. RICHMOND ◽  
M. A. PRICE ◽  
R. B. BERG
Keyword(s):  
Subcutaneous Fat ◽  
Fat Distribution ◽  
Allometric Equation ◽  
Muscle Weight ◽  
Constant Weight ◽  
Independent Variables ◽  
Fat Depots ◽  
Wide Range ◽  
Sex Type ◽  
Breed Differences

The growth and distribution of fat from 163 pig carcasses were compared among five breeds (Duroc × Yorkshire (D × Y), Hampshire × Yorkshire (H × Y), Yorkshire (Y × Y), Yorkshire × Lacombe-Yorkshire (Y × L-Y) and Lacombe × Yorkshire (L × Y)) and two sex-types (barrows and gilts) over a wide range in carcass weight. The growth pattern of fat and the fat depots were estimated from the allometric equation (Y = aXb) using side muscle weight and side fat weight separately as independent variables. Growth coefficients (b) for intermuscular and subcutaneous fat depots were similar for the hindquarter but the intermuscular depot coefficient was slightly higher for the forequarter. The coefficient for body cavity fat was highest in all comparisons. No significant differences were detected for coefficients among breeds and between sexes using both total muscle and total side fat as independent variables. Significant breed and sex-type differences were found in the fat depots at a constant weight of side muscle. This would indicate that breed differences in fatness seemed to be more influenced by the initiation of fattening at different muscle weights than by any inherent differences in rate of fattening. Significant breed differences were also found in the fat depots at a constant fat weight, indicating that breed may influence fat distribution. Sex-type had no effect on fat distribution when the evaluation was made at constant fatness.

scholarly journals Integrative cBioPortal Analysis Revealed Molecular Mechanisms That Regulate EGFR-PI3K-AKT-mTOR Pathway in Diffuse Gliomas of the Brain

Cancers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 3247
Author(s):  
Petar Brlek ◽  
Anja Kafka ◽  
Anja Bukovac ◽  
Nives Pećina-Šlaus
Keyword(s):  
Large Scale ◽  
Molecular Mechanisms ◽  
In Silico Analysis ◽  
Total Sample ◽  
Mtor Signaling ◽  
Biological Behavior ◽  
Mrna Transcription ◽  
Diffuse Gliomas ◽  
New Treatment ◽  
Using Data

Diffuse gliomas are a heterogeneous group of tumors with aggressive biological behavior and a lack of effective treatment methods. Despite new molecular findings, the differences between pathohistological types still require better understanding. In this in silico analysis, we investigated AKT1, AKT2, AKT3, CHUK, GSK3β, EGFR, PTEN, and PIK3AP1 as participants of EGFR-PI3K-AKT-mTOR signaling using data from the publicly available cBioPortal platform. Integrative large-scale analyses investigated changes in copy number aberrations (CNA), methylation, mRNA transcription and protein expression within 751 samples of diffuse astrocytomas, anaplastic astrocytomas and glioblastomas. The study showed a significant percentage of CNA in PTEN (76%), PIK3AP1 and CHUK (75% each), EGFR (74%), AKT2 (39%), AKT1 (32%), AKT3 (19%) and GSK3β (18%) in the total sample. Comprehensive statistical analyses show how genomics and epigenomics affect the expression of examined genes differently across various pathohistological types and grades, suggesting that genes AKT3, CHUK and PTEN behave like tumor suppressors, while AKT1, AKT2, EGFR, and PIK3AP1 show oncogenic behavior and are involved in enhanced activity of the EGFR-PI3K-AKT-mTOR signaling pathway. Our findings contribute to the knowledge of the molecular differences between pathohistological types and ultimately offer the possibility of new treatment targets and personalized therapies in patients with diffuse gliomas.

scholarly journals Loss of histone methyltransferase ASH1L in the developing mouse brain causes autistic-like behaviors

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yuen Gao ◽  
Natalia Duque-Wilckens ◽  
Mohammad B. Aljazi ◽  
Yan Wu ◽  
Adam J. Moeser ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mouse Brain ◽  
Molecular Mechanisms ◽  
Gene Mutations ◽  
Autism Spectrum ◽  
Normal Brain ◽  
Critical Function ◽  
Developmental Defects ◽  
Neurodevelopmental Disease ◽  
Developing Mouse Brain

AbstractAutism spectrum disorder (ASD) is a neurodevelopmental disease associated with various gene mutations. Recent genetic and clinical studies report that mutations of the epigenetic gene ASH1L are highly associated with human ASD and intellectual disability (ID). However, the causality and underlying molecular mechanisms linking ASH1L mutations to genesis of ASD/ID remain undetermined. Here we show loss of ASH1L in the developing mouse brain is sufficient to cause multiple developmental defects, core autistic-like behaviors, and impaired cognitive memory. Gene expression analyses uncover critical roles of ASH1L in regulating gene expression during neural cell development. Thus, our study establishes an ASD/ID mouse model revealing the critical function of an epigenetic factor ASH1L in normal brain development, a causality between Ash1L mutations and ASD/ID-like behaviors in mice, and potential molecular mechanisms linking Ash1L mutations to brain functional abnormalities.

scholarly journals New Insights into the Pathogenesis of Systemic Mastocytosis

2021 ◽  
Vol 22 (9) ◽  
pp. 4900
Author(s):  
Zhixiong Li
Keyword(s):  
Molecular Mechanisms ◽  
Kinase Inhibitor ◽  
Systemic Mastocytosis ◽  
Treatment Strategies ◽  
The United States ◽  
European Medicines Agency ◽  
Myeloid Neoplasm ◽  
Organ Systems ◽  
United States Food ◽  
Kit D816v

Mastocytosis is a type of myeloid neoplasm characterized by the clonal, neoplastic proliferation of morphologically and immunophenotypically abnormal mast cells that infiltrate one or more organ systems. Systemic mastocytosis (SM) is a more aggressive variant of mastocytosis with extracutaneous involvement, which might be associated with multi-organ dysfunction or failure and shortened survival. Over 80% of patients with SM carry the KIT D816V mutation. However, the KIT D816V mutation serves as a weak oncogene and appears to be a late event in the pathogenesis of mastocytosis. The management of SM is highly individualized and was largely palliative for patients without a targeted form of therapy in past decades. Targeted therapy with midostaurin, a multiple kinase inhibitor that inhibits KIT, has demonstrated efficacy in patients with advanced SM. This led to the recent approval of midostaurin by the United States Food and Drug Administration and European Medicines Agency. However, the overall survival of patients treated with midostaurin remains unsatisfactory. The identification of genetic and epigenetic alterations and understanding their interactions and the molecular mechanisms involved in mastocytosis is necessary to develop rationally targeted therapeutic strategies. This review briefly summarizes recent developments in the understanding of SM pathogenesis and potential treatment strategies for patients with SM.

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