Breast cancer (BC) is the most common malignancy affecting Western women today. It is estimated that as many as 10% of BC cases can be attributed to germline variants. However, the genetic basis of the majority of familial BC cases has yet to be identified.
View Article and Find Full Text PDFBackground: Next-generation sequencing (NGS) has significantly transformed the landscape of identifying disease-causing genes associated with genetic disorders. However, a substantial portion of sequenced patients remains undiagnosed. This may be attributed not only to the challenges posed by harder-to-detect variants, such as non-coding and structural variations but also to the existence of variants in genes not previously associated with the patient's clinical phenotype.
View Article and Find Full Text PDFRecent advances in genomic technologies expand the scope and efficiency of preimplantation genetic testing (PGT). We previously developed Haploseek, a clinically-validated, variant-agnostic comprehensive PGT solution. Haploseek is based on microarray genotyping of the embryo's parents and relatives, combined with low-pass sequencing of the embryos.
View Article and Find Full Text PDFOvarian dysgenesis (OD), an XX disorder of sex development, presents with primary amenorrhea, hypergonadotrophic hypogonadism, and infertility. In an Ashkenazi Jewish patient with OD, whole exome sequencing identified compound heterozygous frameshifts in FIGNL1, a DNA damage response (DDR) gene: c.189del and c.
View Article and Find Full Text PDFBiallelic variants in are associated with a slowly progressive syndrome characterized by intellectual disability, spinocerebellar ataxia, cognitive decline and psychosis. The pitrilysin metallopeptidase 1 (PITRM1) is a mitochondrial matrix enzyme, which digests diverse oligopeptides, including the mitochondrial targeting sequences (MTS) that are cleaved from proteins imported across the inner mitochondrial membrane by the mitochondrial processing peptidase (MPP). Mitochondrial peptidases also play a role in the maturation of Frataxin, the protein affected in Friedreich's ataxia.
View Article and Find Full Text PDFPathogenic variants in LRBA, encoding the LPS Responsive Beige-Like Anchor (LRBA) protein, are responsible for recessive, early-onset hypogammaglobulinemia, severe multi-organ autoimmunity, and lymphoproliferation, with increased risk for malignancy. LRBA deficiency has a wide clinical spectrum with variable age of onset and disease severity. Three apparently unrelated patients with LRBA deficiency, of Georgian Jewish descent, were homozygous for LRBA c.
View Article and Find Full Text PDFObjective: To determine the yield of genetic diagnoses using chromosomal microarray (CMA) and trio whole exome sequencing (WES), separately and combined, among patients with cryptogenic cerebral palsy (CP).
Methods: Trio WES of patients with prior CMA analysis for cryptogenic CP, defined as disabling, non-progressive motor symptoms beginning before the age of 3 years without known cause.
Results: Given both CMA analysis and trio WES, clinically significant genetic findings were identified for 58% of patients (26 of 45).
Purpose: We previously developed Haploseek, a method for comprehensive preimplantation genetic testing (PGT). However, some key features were missing, and the method has not yet been systematically validated.
Methods: We extended Haploseek to incorporate DNA from embryo grandparents and to allow testing of variants on chromosome X or in regions where parents share common haplotypes.
Frasier syndrome (FS), a rare disease caused by inherited or de novo mutation in Wilm's Tumor suppressor gene 1 (WT1), is characterized by slow progressive nephropathy, XY gonadal dysgenesis (XY-DSD), and increased risk for gonadal tumors. Early childhood (1-6 years) nephropathy progresses with age to refractory nephrotic syndrome, and end-stage renal failure in late adolescence, when delayed puberty and/or primary amenorrhea are clinically evident. We report a unique case of FS presenting initially with primary amenorrhea at 16 years, without previous or concomitant renal damage.
View Article and Find Full Text PDFDeficiency of the endoplasmic reticulum transmembrane protein ARV1 leads to epileptic encephalopathy in humans and in mice. ARV1 is highly conserved, but its function in human cells is unknown. Studies of yeast arv1 null mutants indicate that it is involved in a number of biochemical processes including the synthesis of sphingolipids and glycosylphosphatidylinositol (GPI), a glycolipid anchor that is attached to the C-termini of many membrane bound proteins.
View Article and Find Full Text PDFGlycosylphosphatidylinositol (GPI) is synthesized in the endoplasmic reticulum (ER) and added onto proteins to form GPI-anchored proteins. Among the many proteins involved in this process, ACAT-related enzyme-2 required for viability 1 (Arv1) is a candidate, functioning as a flippase that translocates GPI intermediates from the cytoplasmic side into the luminal side of the ER membranes. Here, we show that the deletion of the ARV1 gene in yeast leads to cold-sensitive defects in cell growth and GPI anchor synthesis.
View Article and Find Full Text PDFJ Pediatr Gastroenterol Nutr
June 2020
Purpose: Mutations in the gene HSD17B3 encoding the 17-beta hydroxysteroid dehydrogenase 3 enzyme cause testosterone insufficiency leading to XY disorders of sex development. In this study the clinical and molecular characteristics of three patients from consanguineous families are elucidated.
Methods: We identified three patients from two unrelated families with XY DSD and a novel homozygous HSD17B3:c.
Processing of Precursor RNA 1 (POP1) is a core protein component shared by two essential closely related eukaryotic ribonucleoprotein complexes: RNase MRP (the mitochondrial RNA processing ribonuclease) and RNase P. Recently, five patients harboring mutations in POP1 have been reported with severe spondylo-epi-metaphyseal dysplasia and extremely short stature. We report a unique clinical phenotype resulting from the novel homozygous R211Q POP1 mutation in three patients from one family, presenting with severe short stature but only subtle skeletal dysplastic changes that are merely metaphyseal.
View Article and Find Full Text PDFPrenatal genetic testing is not generally applicable to the very early stages of pregnancy (prior to week 8 gestation), a time period that is crucial to pregnant couples with high risk for transmission of genetic disease to their fetus. Therefore, we developed a new ultra-sensitive targeted next generation sequencing method for noninvasive haplotype-based paternal allele exclusion testing of the cystic fibrosis-associated gene, CFTR. This new method was compared to a conventional library prep and sequencing analysis method and all test results were validated by amniotic fluid testing at later stages of pregnancy.
View Article and Find Full Text PDFThe causes of ovarian dysgenesis remain incompletely understood. Two sisters with XX ovarian dysgenesis carried compound heterozygous truncating mutations in the BRCA2 gene that led to reduced BRCA2 protein levels and an impaired response to DNA damage, which resulted in chromosomal breakage and the failure of RAD51 to be recruited to double-stranded DNA breaks. The sisters also had microcephaly, and one sister was in long-term remission from leukemia, which had been diagnosed when she was 5 years old.
View Article and Find Full Text PDFMutations in Vaccinia-related kinase 1 (VRK1) have emerged as a cause of severe neuronal phenotypes in human, including brain developmental defects and degeneration of spinal motor neurons, leading to Spinal Muscular Atrophy (SMA) or early onset Amyotrophic Lateral Sclerosis (ALS). Vrk1 gene-trap partial Knockout (KO) mice (Vrk1), which express decreased levels of Vrk1, are sterile due to impaired gamete production. Here, we examined whether this mouse model also presents neuronal phenotypes.
View Article and Find Full Text PDFObjective: To identify the genetic basis of a childhood-onset syndrome of variable severity characterised by progressive spinocerebellar ataxia, mental retardation, psychotic episodes and cerebellar atrophy.
Methods: Identification of the underlying mutations by whole exome and whole genome sequencing. Consequences were examined in patients' cells and in yeast.
Breast cancer among Palestinian women has lower incidence than in Europe or North America, yet is very frequently familial. We studied genetic causes of this familial clustering in a consecutive hospital-based series of 875 Palestinian patients with invasive breast cancer, including 453 women with diagnosis by age 40, or with breast or ovarian cancer in a mother, sister, grandmother or aunt ("discovery series"); and 422 women diagnosed after age 40 and with negative family history ("older-onset sporadic patient series"). Genomic DNA from women in the discovery series was sequenced for all known breast cancer genes, revealing a pathogenic mutation in 13% (61/453) of patients.
View Article and Find Full Text PDFObjective: To identify the genetic basis of a recessive congenital neurologic syndrome characterized by severe hypotonia, arthrogryposis, and respiratory failure.
Methods: Identification of the responsible gene by exome sequencing and assessment of the effect of the mutation on protein stability in transfected rat neuronal-like PC12 cells.
Results: Two brothers from a nonconsanguineous Yemeni Jewish family manifested at birth with severe hypotonia and arthrogryposis.
Objective: To identify the genetic basis of a recessive syndrome characterized by prenatal hyperechogenic brain foci, congenital microcephaly, hypothalamic midbrain dysplasia, epilepsy, and profound global developmental disability.
Methods: Identification of the responsible gene by whole exome sequencing and homozygosity mapping.
Results: Ten patients from 4 consanguineous Palestinian families manifested in utero with hyperechogenic brain foci, microcephaly, and intrauterine growth retardation.
Recessive CRB2 mutations were recently reported to cause both steroid resistant nephrotic syndrome and prenatal onset ventriculomegaly with kidney disease. We report two Ashkenazi Jewish siblings clinically diagnosed with ciliopathy. Both presented with severe congenital hydrocephalus and mild urinary tract anomalies.
View Article and Find Full Text PDFOvarian development and maintenance are poorly understood; however, diseases that affect these processes can offer insights into the underlying mechanisms. XX female gonadal dysgenesis (XX-GD) is a rare, genetically heterogeneous disorder that is characterized by underdeveloped, dysfunctional ovaries, with subsequent lack of spontaneous pubertal development, primary amenorrhea, uterine hypoplasia, and hypergonadotropic hypogonadism. Here, we report an extended consanguineous family of Palestinian origin, in which 4 females exhibited XX-GD.
View Article and Find Full Text PDFWe report on the derivation of a diploid 46(XX) human embryonic stem cell (HESC) line that is homozygous for the common deletion associated with Spinal muscular atrophy type 1 (SMA) from a pathenogenetic embryo. By characterizing the methylation status of three different imprinted loci (MEST, SNRPN and H19), monitoring the expression of two parentally imprinted genes (SNRPN and H19) and carrying out genome-wide SNP analysis, we provide evidence that this cell line was established from the activation of a mutant oocyte by diploidization of the entire genome. Therefore, our SMA parthenogenetic HESC (pHESC) line provides a proof-of-principle for the establishment of diseased HESC lines without the need for gene manipulation.
View Article and Find Full Text PDFBackground: Noninvasive prenatal testing can be used to accurately detect chromosomal aneuploidies in circulating fetal DNA; however, the necessity of parental haplotype construction is a primary drawback to noninvasive prenatal diagnosis (NIPD) of monogenic disease. Family-specific haplotype assembly is essential for accurate diagnosis of minuscule amounts of circulating cell-free fetal DNA; however, current haplotyping techniques are too time-consuming and laborious to be carried out within the limited time constraints of prenatal testing, hampering practical application of NIPD in the clinic. Here, we have addressed this pitfall and devised a universal strategy for rapid NIPD of a prevalent mutation in the Ashkenazi Jewish (AJ) population.
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