Three novel genes tied to mandibular prognathism in eastern Mediterranean families.

INTRODUCTION: Mandibular prognathism (MP) is subject to major polygenic influence and segregates within families in autosomal dominance with variable expressivity and incomplete penetrance. We aimed to identify the inheritance pattern and genes and loci involved in the development of MP in Mediterranean families and to evaluate the dentoskeletal characteristics of affected individuals. METHODS: Fifty-one eastern Mediterranean families with individuals affected by MP were identified. Data and biospecimens were collected from 14 of the families, including clinical examination, lateral cephalography (on subjects with Class III malocclusion), and 5 mL blood drawn from consenting affected and nonaffected relatives. Next-generation sequencing (NGS) was performed on 8 families (7 Lebanese, 1 Lebanese/Syrian), including large numbers of affected individuals over many generations and severe conditions, with the use of whole-exome sequencing. RESULTS: Most pedigrees suggested autosomal-dominant inheritance with an equal number of affected male and female individuals. Affected individuals had macrognathic and prognathic mandibles with dentoalveolar compensation. Genetic screening did not correspond with previously reported MP-linked genes, but yielded 3 novel genes (C1orf167, NBPF8, NBPF9) on chromosome 1 potentially responsible for mandibular development and macrognathism. CONCLUSIONS: In this first genetic study with the use of NGS on the largest reported number of families with MP, novel genes (C1orf167, NBPF8, NBPF9) were associated with familial MP in the eastern Mediterranean population.

Statins Modulate Cyclooxygenase-2 and Microsomal Prostaglandin E Synthase-1 in Human Hepatic Myofibroblasts.

Statins have been shown to exert anti-inflammatory and anti-fibrogenic properties in the liver. In the present study, we explored the mechanisms underlying anti-fibrogenic effects of statins in isolated hepatic myofibroblasts and focused on cyclooxyegnase-2, a major anti-proliferative pathway in these cells. We show that simvastatin and fluvastatin inhibit thymidine incorporation in hMF in a dose-dependent manner. Pretreatment of cells with NS398, a COX-2 inhibitor, partially blunted this effect. cAMP levels, essential to the inhibition of hMF proliferation, were increased by statins and inhibited by non-steroidal anti-inflammatory drugs. Since statins modify prenylation of some important proteins in gene expression, we investigated the targets involved using selective inhibitors of prenyltransferases. Inhibition of geranylgeranylation resulted in the induction of COX-2 and mPGES-1. Using gel retardation assays, we further demonstrated that statins potentially activated the NFκB and CRE/E-box binding for COX-2 promoter and the binding of GC-rich regions and GATA for mPGES-1. Together these data demonstrate that statin limit hepatic myofibroblasts proliferation via a COX-2 and mPGES-1 dependent pathway. These data suggest that statin-dependent increase of prostaglandin in hMF contributes to its anti-fibrogenic effect.

BRCA1 and BRCA2 mutations in ethnic Lebanese Arab women with high hereditary risk breast cancer.

PURPOSE: Breast cancer is the most common malignancy among women in Lebanon and in Arab countries, with 50% of cases presenting before the age of 50 years. METHODS: Between 2009 and 2012, 250 Lebanese women with breast cancer who were considered to be at high risk of carrying BRCA1 or BRCA2 mutations because of presentation at young age and/or positive family history (FH) of breast or ovarian cancer were recruited. Clinical data were analyzed statistically. Coding exons and intron-exon boundaries of BRCA1 and BRCA2 were sequenced from peripheral blood DNA. All patients were tested for BRCA1 rearrangements using multiplex ligation-dependent probe amplification (MLPA). BRCA2 MLPA was done in selected cases. RESULTS: Overall, 14 of 250 patients (5.6%) carried a deleterious BRCA mutation (7 BRCA1, 7 BRCA2) and 31 (12.4%) carried a variant of uncertain significance. Eight of 74 patients (10.8%) aged ≤40 years with positive FH and only 1 of 74 patients (1.4%) aged ≤40 years without FH had a mutated BRCA. Four of 75 patients (5.3%) aged 41-50 years with FH had a deleterious mutation. Only 1 of 27 patients aged >50 years at diagnosis had a BRCA mutation. All seven patients with BRCA1 mutations had grade 3 infiltrating ductal carcinoma and triple-negative breast cancer. Nine BRCA1 and 17 BRCA2 common haplotypes were observed. CONCLUSION: Prevalence of deleterious BRCA mutations is lower than expected and does not support the hypothesis that BRCA mutations alone cause the observed high percentage of breast cancer in young women of Lebanese and Arab descent. Studies to search for other genetic mutations are recommended.

Low-density lipoprotein levels and not mutation status predict intima-media thickness in familial hypercholesterolemia.

BACKGROUND: Intima-media thickness (IMT) is a well-described marker of cardiovascular disease. In this study we aim to determine whether low-density lipoprotein (LDL) levels and disease-related mutation status can predict IMT in patients with severe familial hypercholesterolemia (FH) referred for or on LDL apheresis. METHODS: Genetic screening, lipid profile testing, and IMT measurements were performed on a series of 33 severe FH patients (19 homozygous) on LDL apheresis treatments (LDL 447 ± 151 mg/dL, age range 6-60 years). Data were then compared with literature IMT-LDL data for normal subjects, mild FH patients, and severe FH patients (18, 41, and 6 studies, respectively). RESULTS: Age-adjusted IMT was linearly related to LDL levels over a wide range of values (<500 mg/dL), except for the severe FH no-apheresis cohort. Alternatively, our severe FH population (mostly on apheresis) did follow the mild FH/control age-adjusted IMT-LDL relation. CONCLUSIONS: In severe FH, measuring LDL levels is more predictive of increased IMT than genetic screening.

Role of glucagon-like peptide-1 analogues on insulin receptor regulation in diabetic rat hearts.

This study focused on the regulation and affinity modulation of the insulin receptor of coronary endothelium and cardiomyocytes in nondiabetic and STZ-induced type 1 diabetic rats. Male rats were divided into the following 9 groups: nondiabetic (N), nondiabetic treated with exendin-4 (NE), nondiabetic treated with dipeptidyl peptidase IV (DPP-IV) inhibitor (NDp), diabetic (D), diabetic treated with insulin (DI), diabetic treated with exendin-4 (DE), diabetic co-treated with insulin and exendin-4 (DIE), diabetic treated with DPP-IV inhibitor (DDp), and diabetic co-treated with insulin and DPP-IV inhibitor (DIDp). After the rats were treated for 1 month, a first-order Bessel function was employed to estimate the insulin binding affinity (with time constant tau = 1/k-n) to its receptors on the coronary endothelium and cardiomyocytes using CHAPS-untreated and CHAPS-treated heart perfusion, respectively. The results showed that diabetes (D) decreased the tau value on the coronary endothelium and increased it on cardiomyocytes compared with the nondiabetic group (N). Treatment with insulin and (or) exendin-4, a glucagon-like peptide-1 (GLP-1) analogue, increased tau on the coronary endothelium only. On the coronary endothelium, tau values of DI and DIDp were normalized. Western blots of the insulin receptor showed upregulation in D, downregulation in DI, and normalization in DE and DDp. Immunohistochemistry and RT-PCR findings indicated atrial natriuretic factor (ANF) in all diabetic ventricles, thus ascertaining hypertrophy. Therefore, negative myocardial effects related to the insulin receptor were diminished in diabetic rats treated with DPP-IV inhibitor and, more efficiently, by exendin-4.

NKX2-5 mutations in an inbred consanguineous population: genetic and phenotypic diversity.

NKX2-5 mutations are associated with different forms of congenital heart disease. Despite the knowledge gained from molecular and animal studies, genotype-phenotype correlations in humans are limited by the lack of large cohorts and the incomplete assessment of family members. We hypothesized that studying the role of NKX2-5 in inbred populations with homogeneous genetic backgrounds and high consanguinity rates such as Lebanon could help closing this gap. We sequenced NKX2-5 in 188 index CHD cases (25 with ASD). Five variants (three segregated in families) were detected in eleven families including the previously documented p.R25C variant, which was found in seven patients from different families, and in one healthy individual. In 3/5 familial dominant ASD cases, we identified an NKX2-5 mutation. In addition to the heterogeneity of NKX2-5 mutations, a diversity of phenotypes occurred within the families with predominant ASD and AV block. We did in fact identify a large prevalence of Sudden Cardiac Death (SCD) in families with truncating mutations, and two patients with coronary sinus disease. NKX2-5 is thus responsible for dominant familial ASD even in consanguineous populations, and a wide genetic and phenotypic diversity is characteristic of NKX2-5 mutations in the Lebanese population.

Diet, genetics, and disease: a focus on the middle East and north Africa region.

The Middle East and North Africa (MENA) region suffers a drastic change from a traditional diet to an industrialized diet. This has led to an unparalleled increase in the prevalence of chronic diseases. This review discusses the role of nutritional genomics, or the dietary signature, in these dietary and disease changes in the MENA. The diet-genetics-disease relation is discussed in detail. Selected disease categories in the MENA are discussed starting with a review of their epidemiology in the different MENA countries, followed by an examination of the known genetic factors that have been reported in the disease discussed, whether inside or outside the MENA. Several diet-genetics-disease relationships in the MENA may be contributing to the increased prevalence of civilization disorders of metabolism and micronutrient deficiencies. Future research in the field of nutritional genomics in the MENA is needed to better define these relationships.

Familial hypercholesterolemia: the lipids or the genes?

Familial Hypercholesterolemia (FH) is a common cause of premature cardiovascular disease and is often undiagnosed in young people. Although the disease is diagnosed clinically by high LDL cholesterol levels and family history, to date there are no single internationally accepted criteria for the diagnosis of FH. Several genes have been shown to be involved in FH; yet determining the implications of the different mutations on the phenotype remains a hard task. The polygenetic nature of FH is being enhanced by the discovery of new genes that serve as modifiers. Nevertheless, the picture is still unclear and many unknown genes contributing to the phenotype are most likely involved. Because of this evolving polygenetic nature, the diagnosis of FH by genetic testing is hampered by its cost and effectiveness.In this review, we reconsider the clinical versus genetic nomenclature of FH in the literature. After we describe each of the genetic causes of FH, we summarize the known correlation with phenotypic measures so far for each genetic defect. We then discuss studies from different populations on the genetic and clinical diagnoses of FH to draw helpful conclusions on cost-effectiveness and suggestions for diagnosis.