Unaffected Carriers Research Articles

Polygenic risk impacts PDGFRA mutation penetrance in non-syndromic cleft lip and palate.

Non-syndromic cleft lip with or without cleft palate (NSCL/P) is a common, severe craniofacial malformation that imposes significant medical, psychosocial and financial burdens. NSCL/P is a multifactorial disorder with genetic and environmental factors playing etiologic roles. Currently, only 25% of the genetic variation underlying NSCL/P has been identified by linkage, candidate gene and genome-wide association studies. In this study, whole-genome sequencing and genome-wide genotyping followed by polygenic risk score (PRS) and linkage analyses were used to identify the genetic etiology of NSCL/P in a large three-generation family. We identified a rare missense variant in PDGFRA (c.C2740T; p.R914W) as potentially etiologic in a gene-based association test using pVAAST (P = 1.78×10-4) and showed decreased penetrance. PRS analysis suggested that variant penetrance was likely modified by common NSCL/P risk variants, with lower scores found among unaffected carriers. Linkage analysis provided additional support for PRS-modified penetrance, with a 7.4-fold increase in likelihood after conditioning on PRS. Functional characterization experiments showed that the putatively causal variant was null for signaling activity in vitro; further, perturbation of pdgfra in zebrafish embryos resulted in unilateral orofacial clefting. Our findings show that a rare PDGFRA variant, modified by additional common NSCL/P risk variants, have a profound effect on NSCL/P risk. These data provide compelling evidence for multifactorial inheritance long postulated to underlie NSCL/P and may explain some unusual familial patterns.

Limb Girdle Muskuler Distrofi Tip 2a: Vaka Sunumu

Limb Girdle Muscular Disease (LGMD) comprise a group of inherited muscular distrophy with chronic progressive weakness of hip and shoulder girdles. The inheritance pattern is either autosomal dominant (LGMD1) or autosomal recessive (LGMD2). LGMD 2A is known as calpainopathy in which there was a defect of gene encoding the protein named as calpain. There are three calpainopathy phenotypes according to distribution of muscle weakness and age at onset. In this report, we presented an asymptomatic child with persistant hyper CKemia diagnosed with muscle biopsy and genetic testing. Genetical examination results of the patient showed homozygote mutation of CAPN3 gene(c.2092C>A) and parents revealed that they were heterozygous unaffected carriers.

334 Hereditary transthyretin amyloidosis: main features and profiles of different clinical phenotypes

Abstract Aims Hereditary transthyretin-related amyloidosis (h-ATTR) is a systemic infiltrative disease caused by a single amino acid mutation on the transthyretin (TTR) gene, which destabilizes the protein and can determine its deposition on multiple organs, including heart and peripheral nervous system. We aimed to characterize and compare clinical, instrumental, and prognostic features of patients affected by h-ATTR by dividing the population into the disease’s main phenotypes (unaffected carriers, cardiac, neurological or mixed phenotype). Methods and results Two hundred and eighty-five subjects of a single-centre cohort with a recognized pathogenic mutation on TTR gene were retrospectively included in the analysis. Phenotypes of disease were defined at baseline. Neurological phenotype (NP) was defined according to sensorimotor and/or autonomic dysfunction, while cardiac phenotype (CP) was defined in the presence of unexplained maximum wall thickness >12 mm and other typical echocardiographic findings. Unaffected carriers (UC) and mixed phenotypes (MP) presented none or both of the above-mentioned features, respectively. Two hundred and ten patients showed clinical signs of the disease, 37 (13%) with CP, 65 (23%) with NP and 108 (38%) with MP, while 75 subjects (26%) were UC. Ile68Leu was the most represented mutation (96 subjects, 34%), followed by Val30Met (21%) and Glu89Gln (13%). NP patients (mostly Val30Met) had mPND score >1 in 45% of patients, were younger at diagnosis (mean 47 years, P < 0.001 vs. CP/MP), and sex was equally distributed. In contrast, CP patients were older at diagnosis (mean 70 years, P < 0.001 vs. CP/MP), predominantly male (as well as in MP) with a higher incidence of tunnel carpal syndrome and a shorter time interval between onset of symptoms and diagnosis (mean 17 months, P < 0.001 vs. CP/MP). NYHA class, ECG findings, left ventricular wall thickness, and ejection fraction did not significantly differ between CP and MP. After a mean follow-up of 59 months, 98 (34%) patients died. On a Kaplan–Meier survival analysis, mean survival times were 208, 123, 150, and 95 months for UC, CP, NP, and MP, respectively, with a statistically significant difference in affected patients between NP and MP (P = 0.012). Conclusions H-ATTR is a rare systemic disorder whose natural history, including age of onset, clinical characteristics, and instrumental findings, is strongly influenced by primary phenotypes, ranging from the excellent prognosis of unaffected carriers to the inauspicious outcome of mixed phenotypes.

Abstract 11176: Family Screening in Dilated Cardiomyopathy; Long-Term Incidence and Potential for Limiting Follow-Up

Introduction: Guidelines recommend family screening in dilated cardiomyopathy (DCM) to uncover pre-symptomatic familial DCM (FDC). So far, no guidelines provide specific recommendations on the intensity and frequency of follow-up screening. This study sought to provide the first detailed estimates of the incidence of FDC during follow-up and identify baseline markers which could inform future follow-up of relatives. Methods: The study was a retrospective, observational, longitudinal cohort study of relatives to DCM probands screened at a regional assembly of family screening clinics in Copenhagen, Denmark, from 2006 to 2020. Results: In total, 563 relatives (50% women) from 211 families were included. At baseline, 124 relatives (22%) were diagnosed with FDC: 97 (18%) as a result of screening and 27 (5%) with symptom-onset prior to screening. Genetic sequencing identified the etiology of DCM in 35% of families and classified 90 relatives (17%) as unaffected carriers (n=44) or relatives not at risk of FDC (n=46). As such, the combined clinical and genetic baseline-yield was 31%. In 439 relatives considered unaffected at baseline, 45 (10%) were diagnosed with FDC during follow-up (median 5.0 years). The age-standardized incidence rate of FDC was 2.0% per person-year [CI: 1.4-2.8%] with higher rates in men vs women (3.0% vs 1.4% per person-year). In relatives without predictive genetic findings (n=349), non-diagnostic abnormal baseline-findings on ECG or echocardiography was associated with a higher incidence rate of FDC (figure A), while the risk was low in relatives with normal findings (0.4% vs 4.7% per person-year; figure B). Conclusion: Systematic family screening identified FDC or genetic predisposition to FDC in 1 out of 3 relatives at baseline. Relatives without predictive genetic findings and with normal findings on ECG and echocardiography at baseline had a low risk of developing FDC. Follow-up can be limited and may not be warranted in these relatives.

Analysis of characteristics and prognostic impact of phenotypes in hereditary ATTR

Abstract Background Hereditary transthyretin-related amyloidosis (h-ATTR) is a systemic infiltrative disease caused by a single amino acid mutation on the transthyretin (TTR) gene, which destabilizes the protein and can determine its deposition on multiple organs, including heart and peripheral nervous system. Purpose We aimed to characterize and compare clinical, instrumental, and prognostic features of patients affected by h-ATTR by dividing the population into the disease's main phenotypes (unaffected carriers, cardiac, neurological or mixed phenotype). Methods Two hundred and eighty-five subjects of a single-centre cohort with a recognized pathogenic mutation on TTR gene were retrospectively included in the analysis. Phenotypes of disease were defined at baseline. Neurological phenotype (NP) was defined according to sensorimotor and/or autonomic dysfunction, while cardiac phenotype (CP) was defined in the presence of unexplained maximum wall thickness >12 mm and other typical echocardiographic findings. Unaffected carriers (UC) and mixed phenotypes (MP) presented none or both of the above-mentioned features, respectively. Results Two hundred and ten patients showed clinical signs of the disease, 37 (13%) with CP, 65 (23%) with NP and 108 (38%) with MP, while 75 subjects (26%) were UC. Ile68Leu was the most represented mutation (96 subjects, 34%), followed by Val30Met (21%) and Glu89Gln (13%). NP patients (mostly Val30Met) had mPND score >1 in 45% of patients, were younger at diagnosis (mean 47 years, p<0,001 vs CP/MP), and sex was equally distributed. In contrast, CP patients were older at diagnosis (mean 70 years, p<0,001 vs CP/MP), predominantly male (as well as in MP) with a higher incidence of tunnel carpal syndrome and a shorter time interval between onset of symptoms and diagnosis (mean 17 months, p<0,001 vs CP/MP). NYHA class, ECG findings, left ventricular wall thickness and ejection fraction did not significantly differ between CP and MP. After a mean follow-up of 59 months, 98 (34%) patients died. On a Kaplan-Meier survival analysis, mean survival times were 208, 123, 150 and 95 months for UC, CP, NP and MP, respectively, with a statistically significant difference in affected patients between NP and MP (p=0.012). Conclusions H-ATTR is a rare systemic disorder whose natural history, including age of onset, clinical characteristics and instrumental findings, is strongly influenced by primary phenotypes, ranging from the excellent prognosis of unaffected carriers to the inauspicious outcome of mixed phenotypes. Funding Acknowledgement Type of funding sources: None.

Progression of PTH Resistance in Autosomal Dominant Pseudohypoparathyroidism Type Ib Due to Maternal STX16 Deletions.

Maternally inherited STX16 deletions that cause loss of methylation at GNAS exon A/B and thereby reduce Gsα expression are the most frequent cause of autosomal dominant pseudohypoparathyroidism type Ib (AD-PHP1B). Early identification of these disease-causing variants in the children of affected and unaffected female carriers would prompt treatment with calcium and calcitriol once parathyroid hormone (PTH) levels increase, thereby preventing hypocalcemia and associated complications. This study aimed to determine when PTH and calcium abnormalities develop after birth if a STX16 deletion is inherited maternally. Forty-four children of affected (n = 7) or unaffected (n = 7) females with a STX16 deletion were investigated for the presence of these variants. If a deletion was identified, measurement of PTH, calcium, phosphate, and thyrotropin (TSH) was advised. The STX16 deletion that causes AD-PHP1B was identified in 25 children. Pretreatment laboratory results were available for 19 of those cases. Elevated PTH levels were detected by 2 years of age, and these were progressively higher if laboratory testing was first performed after establishing the genetic defect later in life. Total serum calcium levels remained within normal limits until about 5 years of age. TSH levels showed no consistent rise over time. Establishing whether a STX16 deletion is inherited from a female carrier of a disease-causing variant rapidly establishes the diagnosis of AD-PHP1B. Several years before overt hypocalcemia developed, PTH levels increased, thereby establishing the onset of PTH resistance. Our findings provide diagnostic guidance and when treatment with calcium and calcitriol should be considered in order to prevent hypocalcemia and associated sequelae.

3-Methylglutaconic aciduria in carriers of primary carnitine deficiency

The etiology of secondary 3-methylglutaconic aciduria (3-MGA-uria) is not well understood although is thought to be a marker of mitochondrial dysfunction. For this reason, suspicion for a secondary 3-MGA-uria often leads to an extensive clinical and laboratory work-up for mitochondrial disease, although in many cases evidence for mitochondrial dysfunction is never found.3-methylglutaconic aciduria in healthy individuals without known metabolic disease has not been well described. Here, we describe clinical and biochemical features of 23 individuals evaluated at the Greenwood Genetic Center for low plasma free carnitine reported on newborn screening. Of the 23 individuals evaluated, four individuals were diagnosed with primary carnitine deficiency, 16 were identified as carriers for primary carnitine deficiency, and three individuals were determined to be unaffected non-carriers based on molecular and biochemical testing.Elevated 3-MGA (>20 mmol/mol of creatinine) was identified in nine carriers of primary carnitine deficiency, while all unaffected non carriers and all affected individuals with primary carnitine deficiency had a normal 3-MGA level (<20 mmol/mol of creatinine). Average 3-MGA among all carriers was 39.66 mmol/mol of creatinine. Average plasma free carnitine in among all carriers (n = 16) was 13.87 μm/L, and average plasma free carnitine was not significantly different between carriers with and those without elevated 3-MGA (p = 0.66).In summary, we describe elevated 3-MGA as a discriminatory feature in nine healthy carriers of primary carnitine deficiency. Our findings suggest that heterozygosity for pathogenic alterations on SLC22A5 should be considered in the differential for individuals with persistent 3-MGA-uria of unclear etiology.

Are foveal thickness, pit depth, and slopes truly abnormal in unaffected carriers of the LHON variant m.11778G>G?

Are foveal thickness, pit depth, and slopes truly abnormal in unaffected carriers of the LHON variant m.11778G>G?

LIPAD (LRRK2/Luebeck International Parkinson's Disease) Study Protocol: Deep Phenotyping of an International Genetic Cohort.

Background: Pathogenic variants in the Leucine-rich repeat kinase 2 (LRRK2) gene are the most common known monogenic cause of Parkinson's disease (PD). LRRK2-linked PD is clinically indistinguishable from idiopathic PD and inherited in an autosomal dominant fashion with reduced penetrance and variable expressivity that differ across ethnicities and geographic regions.Objective: To systematically assess clinical signs and symptoms including non-motor features, comorbidities, medication and environmental factors in PD patients, unaffected LRRK2 pathogenic variant carriers, and controls. A further focus is to enable the investigation of modifiers of penetrance and expressivity of LRRK2 pathogenic variants using genetic and environmental data.Methods: Eligible participants are invited for a personal or online examination which comprises completion of a detailed eCRF and collection of blood samples (to obtain DNA, RNA, serum/plasma, immune cells), urine as well as household dust. We plan to enroll 1,000 participants internationally: 300 with LRRK2-linked PD, 200 with LRRK2 pathogenic variants but without PD, 100 PD patients with pathogenic variants in the GBA or PRKN genes, 200 patients with idiopathic PD, and 200 healthy persons without pathogenic variants.Results: The eCRF consists of an investigator-rated (1 h) and a self-rated (1.5 h) part. The first part includes the Movement Disorder Society Unified Parkinson's Disease Rating, Hoehn &Yahr, and Schwab & England Scales, the Brief Smell Identification Test, and Montreal Cognitive Assessment. The self-rating part consists of a PD risk factor, food frequency, autonomic dysfunction, and quality of life questionnaires, the Pittsburgh Sleep Quality Inventory, and the Epworth Sleepiness as well as the Hospital Anxiety and Depression Scales. The first 15 centers have been initiated and the first 150 participants enrolled (as of March 25th, 2021).Conclusions: LIPAD is a large-scale international scientific effort focusing on deep phenotyping of LRRK2-linked PD and healthy pathogenic variant carriers, including the comparison with additional relatively frequent genetic forms of PD, with a future perspective to identify genetic and environmental modifiers of penetrance and expressivityClinical Trial Registration:ClinicalTrials.gov, NCT04214509.

Identifying Sequence Variants of 18 Hereditary Ovarian Cancer-Associated Genes in Chinese Epithelial Ovarian Cancer Patients.

Objectives The causes of ovarian cancer (OC) have been confirmed to be closely related to genetic factors. Identifying sequence variants of hereditary ovarian cancer (HOC) susceptibility genes can increase clinical surveillance, facilitate early detection, and provide personalized treatment for patients. This study is aimed at investigating the variation frequency of HOC susceptibility genes in the Chinese population and providing information for the etiology and genetics of OC. Methods 118 epithelial OC patients were recruited in this clinical study. Variants of 18-gene panel were detected in blood samples by next-generation sequencing (NGS) technology. Results Overall, 36.44% (43/118) of patients carried at least one pathogenic variant. Among these, BRCA1 pathogenic variants were detected in 31 (26.27%) patients, and 5 (4.24%) patients carried pathogenic variants of BRCA2. Moreover, 27.12% (32/118) of patients carried variants of unknown significance (VUSs). Importantly, we detected eight variants that were not reported previously. Conclusions Our study enlarged the spectrum of HOC-associated gene sequence variants in the Chinese population and also proved the necessity of multigene testing in epithelial OC patients. The identification of patients with HOC will allow family members to undergo cascade testing where identification of unaffected carriers can facilitate early detection, risk reduction, or prevention of OC and ultimately improve long-term outcomes.

Reassessment of Gene-Elusive Familial Dilated Cardiomyopathy Leading to the Discovery of a Homozygous AARS2 Variant—The Importance of Regular Reassessment of Genetic Findings

Background: AARS2 encodes the mitochondrial protein alanyl-tRNA synthetase 2 (MT-AlaRS), an important enzyme in oxidative phosphorylation. Variants in AARS2 have previously been associated with infantile cardiomyopathy. Case summary: A 4-year-old girl died of infantile-onset dilated cardiomyopathy (DCM) in 1996. Fifteen years later, her 21-year-old brother was diagnosed with DCM and ultimately underwent heart transplantation. Initial sequencing of 15 genes discovered no pathogenic variants in the brother at the time of his diagnosis. However, 9 years later re-screening in an updated screening panel of 129 genes identified a homozygous AARS2 (c.1774C &gt; T) variant. Sanger sequencing of the deceased girl confirmed her to be homozygous for the AARS2 variant, while both parents and a third sibling were all found to be unaffected heterozygous carriers of the AARS2 variant. Discussion: This report underlines the importance of repeated and extended genetic screening of elusive families with suspected hereditary cardiomyopathies, as our knowledge of disease-causing mutations continuously grows. Although identification of the genetic etiology in the reported family would not have changed the clinical management, the genetic finding allows genetic counselling and holds substantial value in identifying at-risk relatives.

Two Approaches for a Genetic Analysis of Pompe Disease: A Literature Review of Patients with Pompe Disease and Analysis Based on Genomic Data from the General Population.

In this study, two different approaches were applied in the analysis of the GAA gene. One was analyzed based on patients with Pompe disease, and the other was analyzed based on GAA genomic data from unaffected carriers in a general population genetic database. For this, GAA variants in Korean and Japanese patients reported in previous studies and in patients reported in the Pompe disease GAA variant database were analyzed as a model. In addition, GAA variants in the Korean Reference Genome Database (KRGDB), the Japanese Multi Omics Reference Panel (jMorp), and the Genome Aggregation Database (gnomAD) were analyzed. Overall, approximately 50% of the pathogenic or likely pathogenic variants (PLPVs) found in unaffected carriers were also found in real patients with Pompe disease (Koreans, 57.1%; Japanese, 46.2%). In addition, there was a moderate positive correlation (Spearman’s correlation coefficient of 0.45–0.69) between the proportion of certain PLPVs in patients and the minor allele frequency of their variants in a general population database. Based on the analysis of general population databases, the total carrier frequency for Pompe disease in Koreans and Japanese was estimated to be 1.7% and 0.7%, respectively, and the predicted genetic prevalence was 1:13,657 and 1:78,013, respectively.

High-throughput Molecular Analysis of Pseudohypoparathyroidism 1b Patients Reveals Novel Genetic and Epigenetic Defects.

Patients with pseudohypoparathyroidism type 1b (PHP1b) show disordered imprinting of the maternal GNAS allele or paternal uniparental disomy (UPD). Genetic deletions in STX16 or in upstream exons of GNAS are present in many familial but not sporadic cases. Characterization of epigenetic and genetic defects in patients with PHP1b. DNA from 84 subjects, including 26 subjects with sporadic PHP1b, 27 affected subjects and 17 unaffected and/or obligate gene carriers from 12 PHP1b families, 11 healthy individuals, and 3 subjects with PHP1a was subjected to quantitative pyrosequencing of GNAS differentially methylated regions (DMRs), microarray analysis, and microsatellite haplotype analysis. Academic medical center. Molecular pathology of PHP1b. Healthy subjects, unaffected family members and obligate carriers of paternal PHP1b alleles, and subjects with PHP1a showed normal methylation of all DMRs. All PHP1b subjects showed loss of methylation (LOM) at the exon A/B DMR. Affected members of 9 PHP1b kindreds showed LOM only at the exon A/B DMR, which was associated with a 3-kb deletion of STX16 exons 4 through 6 in 7 families and a novel deletion of STX16 and adjacent NEPEPL1 in 1 family. A novel NESP deletion was found in 1 of 2 other families with more extensive methylation defects. One sporadic PHP1b had UPD of 20q, 2 had 3-kb STX16 deletions, and 5 had apparent epigenetic mosaicism. We found diverse patterns of defective methylation and identified novel or previously known mutations in 9 of 12 PHP1b families.

Ocular Involvement in Hereditary Transthyretin Amyloidosis: A Case Series Describing Novel Potential Biomarkers.

Hereditary transthyretin amyloidosis (hATTR) is a rare disease caused by a point mutation in the transthyretin (TTR) gene and inherited in an autosomal dominant fashion. TTR is a plasma protein that functions as a carrier for thyroxine (T4) and retinol (vitamin A). Ophthalmological manifestations are due to both the hepatic and ocular production of mutated TTR. In this case series, we report the ocular manifestations of hATTR in eighteen eyes of nine consecutive patients. Corneal nerve abnormalities as well as morphological and functional changes in the retina were investigated. The study was a single-center, retrospective, observational, clinical case series. In all patients, corneal confocal microscopy (CCM), multimodal imaging of the retina, including fundus photography and Optical Coherence Tomography (OCT), as well as rod and cone electroretinography (ERG) were performed. Eight patients had active disease and one was an unaffected carrier. In all study eyes, corneal nerve plexa examined with CCM were poorly represented or absent. Mixed rod-cone and cone ERG b-wave amplitudes were reduced, and photopic b-wave responses were significantly delayed. Photopic Negative Response (PhNR) amplitude was significantly reduced, while PhNR latency was significantly augmented. In 13/18 eyes, vitreous opacities and abnormalities of vitreo-retinal interface were found. The current results highlight the presence of corneal nerve damage. Functional retinal abnormalities, detected by ERG, can be found even in the presence of minimal or absent structural retinal damage. These findings support the use of CCM and ERGs to detect early biomarkers for primary hATTR.

Application of [18F]FLT-PET in pulmonary arterial hypertension: a clinical study in pulmonary arterial hypertension patients and unaffected bone morphogenetic protein receptor type 2mutation carriers.

Pulmonary arterial hypertension is a heterogeneous group of diseases characterized by vascular cell proliferation leading to pulmonary vascular remodelling and ultimately right heart failure. Previous data indicated that 3′-deoxy-3′-[18F]-fluorothymidine (18FLT) positron emission tomography (PET) scanning was increased in pulmonary arterial hypertension patients, hence providing a possible biomarker for pulmonary arterial hypertension as it reflects vascular cell hyperproliferation in the lung. This study sought to validate 18FLT-PET in an expanded cohort of pulmonary arterial hypertension patients in comparison to matched healthy controls and unaffected bone morphogenetic protein receptor type 2 mutation carriers. 18FLT-PET scanning was performed in 21 pulmonary arterial hypertension patients (15 hereditary pulmonary arterial hypertension and 6 idiopathic pulmonary arterial hypertension), 11 unaffected mutation carriers and 9 healthy control subjects. In-depth kinetic analysis indicated that there were no differences in lung 18FLT k3 phosphorylation among pulmonary arterial hypertension patients, unaffected bone morphogenetic protein receptor type 2 mutation carriers and healthy controls. Lung 18FLT uptake did not correlate with haemodynamic or clinical parameters in pulmonary arterial hypertension patients. Sequential 18FLT-PET scanning in three patients demonstrated uneven regional distribution in 18FLT uptake by 3D parametric mapping of the lung, although this did not follow the clinical course of the patient. We did not detect significantly increased lung 18FLT uptake in pulmonary arterial hypertension patients, nor in the unaffected bone morphogenetic protein receptor type 2 mutation carriers, as compared to healthy subjects. The conflicting results with our preliminary human 18FLT report may be explained by a small sample size previously and we observed large variation of lung 18FLT signals between patients, challenging the application of 18FLT-PET as a biomarker in the pulmonary arterial hypertension clinic.

Genetic Dominant Variants in STUB1, Segregating in Families with SCA48, Display In Vitro Functional Impairments Indistinctive from Recessive Variants Associated with SCAR16.

Variants in STUB1 cause both autosomal recessive (SCAR16) and dominant (SCA48) spinocerebellar ataxia. Reports from 18 STUB1 variants causing SCA48 show that the clinical picture includes later-onset ataxia with a cerebellar cognitive affective syndrome and varying clinical overlap with SCAR16. However, little is known about the molecular properties of dominant STUB1 variants. Here, we describe three SCA48 families with novel, dominantly inherited STUB1 variants (p.Arg51_Ile53delinsProAla, p.Lys143_Trp147del, and p.Gly249Val). All the patients developed symptoms from 30 years of age or later, all had cerebellar atrophy, and 4 had cognitive/psychiatric phenotypes. Investigation of the structural and functional consequences of the recombinant C-terminus of HSC70-interacting protein (CHIP) variants was performed in vitro using ubiquitin ligase activity assay, circular dichroism assay and native polyacrylamide gel electrophoresis. These studies revealed that dominantly and recessively inherited STUB1 variants showed similar biochemical defects, including impaired ubiquitin ligase activity and altered oligomerization properties of the CHIP. Our findings expand the molecular understanding of SCA48 but also mean that assumptions concerning unaffected carriers of recessive STUB1 variants in SCAR16 families must be re-evaluated. More investigations are needed to verify the disease status of SCAR16 heterozygotes and elucidate the molecular relationship between SCA48 and SCAR16 diseases.

Neurological involvement in Ile68Leu (p.Ile88Leu) ATTR amyloidosis: not only a cardiogenic mutation

Background Ile68Leu transthyretin-related amyloidosis (ATTR) is known as a mainly or exclusively cardiogenic variant. We hypothesized that an accurate specialized neurological evaluation could reveal a consistent frequency of mixed phenotypes. Methods Forty-six consecutive subjects with transthyretin (TTR) Ile68Leu (p.Ile88Leu) mutation (29 patients and 17 unaffected carriers) underwent an in-depth cardiac and neurologic evaluation at a single center. Results All 29 patients showed cardiac involvement. In 20 (69%) cases, it was associated with neurological abnormalities (i.e. a mixed phenotype): 10 (35% of the total) had signs and symptoms of neuropathy, 5 (17%) had abnormalities at the neurologic specialist examination but without symptoms, and 5 (17%) had abnormal nerve conduction study only. None of the asymptomatic carriers showed neurological abnormalities or cardiac involvement. The Neuropathy Impairment Score was > 5 in seven patients at baseline, and became >5 in six more patients during follow-up. The probability of experiencing a major adverse cardiac event (MACE) during follow-up was higher in the mixed than cardiologic phenotype (p = 0.026). Age and phenotype were independent prognostic predictors of MACE. Conclusion At least two-thirds of patients with Ile68Leu ATTR and amyloidotic cardiomyopathy show an associated – definite or probable – neurologic impairment of variable degree if accurately evaluated in a neurologic setting. This proportion can rise during follow-up. The mixed phenotype carries a worse prognosis compared to the exclusively cardiologic one. These observations show that more patients could be eligible for treatment with gene silencers than currently indicated and highlight the need for an in-depth and continuous multidisciplinary evaluation of Ile68Leu ATTR patients.

Screening for Mutations in Isolated Central Hypothyroidism Reveals a Novel Mutation in Insulin Receptor Substrate 4.

BackgroundCentral hypothyroidism (CeH) is a rare condition affecting approximately 1:16 000- 100 000 individuals. Congenital forms can harm normal development if not detected and treated promptly. Clinical and biochemical diagnosis, especially of isolated CeH, can be challenging. Cases are not usually detected in neonatal screening, which, in most countries, is focused on detection of the more prevalent primary hypothyroidism. Until now, five genetic causes for isolated CeH have been identified. Here we aimed to identify the genetic cause in two brothers with impaired growth diagnosed with CeH at the age of 5 years. We further evaluated the candidate gene variants in a large genetic database.MethodsClinical and biochemical characterization together with targeted next-generation sequencing (NGS) was used to identify the genetic cause in a family of two brothers presenting with CeH. Screening of insulin receptor substrate 4 (IRS4) variants was carried out in the FinnGen database.ResultsA novel monoallelic frameshift mutation c.1712_1713insT, p.Gly572Trp fs*32 in the X-linked IRS4 gene was identified by NGS analysis in both affected males and confirmed using Sanger sequencing. Their mother was an unaffected carrier. In addition to the declined growth at presentation, central hypothyroidism and blunted TRH test, no other phenotypic alterations were found. Diagnostic tests included head MRI, thyroid imaging, bone age, and laboratory tests for thyroid autoantibodies, glucose, insulin and glycosylated hemoglobin levels. Examination of the IRS4 locus in FinnGen (R5) database revealed the strongest associations to a rare Finnish haplotype associated with thyroid disorders (p = 1.3e-7) and hypothyroidism (p = 8.3e-7).ConclusionsHere, we identified a novel frameshift mutation in an X-linked IRS4 gene in two brothers with isolated CeH. Furthermore, we demonstrate an association of IRS4 gene locus to a general thyroid disease risk in the FinnGen database. Our findings confirm the role of IRS4 in isolated central hypothyroidism.

First Report of Novel PTEN variant in breast cancer from Pakistan: A predictive variable of diagnostic importance

Introduction Breast Cancer is the number one cause of cancer related deaths in Pakistani women with an incidence of 1 in 9. This abstract is a part of a larger study that we conducted to identify the variants in 27 possible genes known for breast and ovarian cancer along with several oxidative stress markers. The current objective is to report a predictive novel variant of diagnostic importance in local females with breast cancer. Furthermore, to study the epidemiological and clinical presentation that may be predictive of this variable. Methods After ethical approval and informed consent, we extracted DNA from peripheral blood and conducted next generation sequencing followed by Sanger confirmation. Bioinformatic analysis was performed on ANNOVAR and SNP-Nexus softwares. Results Our results on both softwares indicate that an identical novel Phosphatase and Tension Homolog (PTEN) variant is present in 69% patients. It is a homozygous frameshift substitution (GCGCCG > CCGCCGC) at amino acid position C65S on exon 2 of chromosome 10 from 89623901 to 89623906. It acts at Micro-RNA and Cellular Senescence level of cancer pathways. All PTEN cases showed significant triple negative behavior at estrogen, progesterone and HER2 receptors, associated with adverse outcome. A total of 85% were premenopausal with mean age of 35 years +/- SD 5.611; SE 1.255; range 27-46 years). Their mean age at menarche was 13.25 years +/- SD 0.716; SE 0.160. The mean BMI showed overweight status. Family history was positive and known in only 35% but they were mainly (60%) the outcome of related parents. In majority (75%) of them history of breast feeding was positive and had no difficulty in breast feeding (70%). Around 80% were non-smokers and 100% were non-alcoholics. Most of them (85%) presented with Invasive Ductal Carcinoma and 55% with grade III. They all were homemakers, most (85%) being married and majority (75%) did not receive education above grade 10. Nearly 70% used tap / filtered-tap-water for drinking. They all had unilateral breast cancer of right side mainly (60%). Almost all (95%) detected it by feeling the lump. Mastectomy was performed only in 30% and all of them underwent chemotherapy. Radiotherapy was offered to only 10%. A total of 35% among them had only 1 year post-diagnosis survival. Conclusion This novel variant may be useful for researcher and clinician to expect similar outcome in unaffected carriers. It can be offered as a screening tool to achieve pre-diagnosis around 13 years of age to predict similar clinical manifestation using affordable Sanger technique, even before the breast development. The early diagnosis may improve the outcome.

A Case-Based Clinical Approach to the Investigation, Management and Screening of Families with BRCA2 Related Prostate Cancer.

BRCA2 is the most commonly implicated DNA damage repair gene associated with inherited prostate cancer. BRCA2 deficient prostate cancer typically presents at a younger age, is more poorly differentiated, and is associated with worse survival outcomes than non-BRCA2 associated prostate cancer. Despite these unfavourable prognostic implications, poly-ADP ribose polymerase inhibitors and platinum-based chemotherapy have been identified as potent targeted therapeutic agents towards BRCA1/2 deficient cancer cells. This review article explores the literature surrounding BRCA2-related prostate cancer through a familial clinical scenario. The investigation, diagnosis and management of BRCA2 deficient prostate cancer will be explored, alongside the implications of the identification of a germline pathogenic BRCA2 variant within a family, cascade screening and prostate cancer surveillance in unaffected male BRCA2 carriers. A greater understanding of the molecular pathogenesis of DNA damage repair gene deficient prostate cancer, coupled with new treatment paradigms and widened access to both somatic and germline genetic analysis for prostate cancer patients and their families will hopefully enable the robust implementation of high quality evidence-based clinical pathways for both the management and identification of BRCA2 deficient prostate cancer and improved screening, early detection and prevention strategies for individuals at increased genetic risk of prostate cancer.