A cross-disorder dosage sensitivity map of the human genome.

Rare copy-number variants (rCNVs) include deletions and duplications that occur infrequently in the global human population and can confer substantial risk for disease. In this study, we aimed to quantify the properties of haploinsufficiency (i.e.

Uniparental disomy in a population of 32,067 clinical exome trios.

Purpose: Data on the clinical prevalence and spectrum of uniparental disomy (UPD) remain limited. Trio exome sequencing (ES) presents a comprehensive method for detection of UPD alongside sequence and copy-number variant analysis.

Methods: We analyzed 32,067 ES trios referred for diagnostic testing to create a profile of UPD events and their disease associations.

Correction: Adapting ACMG/AMP sequence variant classification guidelines for single-gene copy-number variants.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Adapting ACMG/AMP sequence variant classification guidelines for single-gene copy number variants.

Purpose: The ability of a single technology, next-generation sequencing, to provide both sequence and copy number variant (CNV) results has driven the merger of clinical cytogenetics and molecular genetics. Consequently, the distinction between the definition of a sequence variant and a CNV is blurry. As the 2015 American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) standards and guidelines for interpretation of sequence variants address CNV classification only sparingly, this study focused on adapting ACMG/AMP criteria for single-gene CNV interpretation.

Copy number variant discrepancy resolution using the ClinGen dosage sensitivity map results in updated clinical interpretations in ClinVar.

Conflict resolution in genomic variant interpretation is a critical step toward improving patient care. Evaluating interpretation discrepancies in copy number variants (CNVs) typically involves assessing overlapping genomic content with focus on genes/regions that may be subject to dosage sensitivity (haploinsufficiency (HI) and/or triplosensitivity (TS)). CNVs containing dosage sensitive genes/regions are generally interpreted as "likely pathogenic" (LP) or "pathogenic" (P), and CNVs involving the same known dosage sensitive gene(s) should receive the same clinical interpretation.

Identification of two 14q32 deletions involving DICER1 associated with the development of DICER1-related tumors.

DICER1 encodes an RNase III endonuclease protein that regulates the production of small non-coding RNAs. Germline mutations in DICER1 are associated with an autosomal dominant hereditary cancer predisposition syndrome that confers an increased risk for the development of several rare childhood and adult-onset tumors, the most frequent of which include pleuropulmonary blastoma, ovarian sex cord-stromal tumors, cystic nephroma, and thyroid gland neoplasia. The majority of reported germline DICER1 mutations are truncating sequence-level alterations, suggesting that a loss-of-function type mechanism drives tumor formation in DICER1 syndrome.

Diagnostic cytogenetic testing following positive noninvasive prenatal screening results: a clinical laboratory practice resource of the American College of Medical Genetics and Genomics (ACMG).

Disclaimer: ACMG Clinical Laboratory Practice Resources are developed primarily as an educational tool for clinical laboratory geneticists to help them provide quality clinical laboratory genetic services. Adherence to these practice resources is voluntary and does not necessarily assure a successful medical outcome. This Clinical Laboratory Practice Resource should not be considered inclusive of all proper procedures and tests or exclusive of other procedures and tests that are reasonably directed to obtaining the same results.

Noninvasive prenatal screening for aneuploidy: positive predictive values based on cytogenetic findings.

Objective: We sought to determine the positive predictive value (PPV) of noninvasive prenatal screening (NIPS) for various aneuploidies based on cases referred for follow-up cytogenetic testing. Secondarily, we wanted to determine the false-negative (FN) rate for those cases with a negative NIPS result.

Study Design: We compared the cytogenetic findings (primarily from chromosome analysis) from 216 cases referred to our laboratories with either a positive or negative NIPS result, and classified NIPS results as true positive, false positive, true negative, or FN.

Assessing copy number from exome sequencing and exome array CGH based on CNV spectrum in a large clinical cohort.

Purpose: Detection of copy-number variation (CNV) is important for investigating many genetic disorders. Testing a large clinical cohort by array comparative genomic hybridization provides a deep perspective on the spectrum of pathogenic CNV. In this context, we describe a bioinformatics approach to extract CNV information from whole-exome sequencing and demonstrate its utility in clinical testing.

Partial deletion of ANKRD11 results in the KBG phenotype distinct from the 16q24.3 microdeletion syndrome.

KBG syndrome (OMIM 148050) is a very rare genetic disorder characterized by macrodontia, distinctive craniofacial abnormalities, short stature, intellectual disability, skeletal, and neurologic involvement. Approximately 60 patients have been reported since it was first described in 1975. Recently mutations in ANKRD11 have been documented in patients with KBG syndrome, and it has been proposed that haploinsufficiency of ANKRD11 is the cause of this syndrome.

A systematic analysis of small supernumerary marker chromosomes using array CGH exposes unexpected complexity.

Purpose: A small supernumerary marker chromosome is often seen in patients with developmental disorders. Prior to array-based comparative genomic hybridization markers were rarely genotyped end to end. In this study, a valid genotype-to-phenotype correlation was possible because the supernumerary marker chromosomes were fully characterized by array-based comparative genomic hybridization in a genome-wide analysis.

Histiocytic sarcoma transdifferentiated from follicular lymphoma presenting as a cutaneous tumor.

Histiocytic sarcoma represents a rare and poorly understood tumor of histiocytic/dendritic cell lineage that can rarely present in the skin. Previously reported cases of histiocytic sarcoma after follicular lymphoma suggested that follicular lymphoma can transdifferentiate into histiocytic sarcoma. We describe another case involving a 40-year old male who developed histiocytic sarcoma in his right thigh 4 years after the diagnosis of grade 1 follicular lymphoma in the left neck.

Holoprosencephaly due to numeric chromosome abnormalities.

Holoprosencephaly (HPE) is the most common malformation of the human forebrain. When a clinician identifies a patient with HPE, a routine chromosome analysis is often the first genetic test sent for laboratory analysis in order to assess for a structural or numerical chromosome anomaly. An abnormality of chromosome number is overall the most frequently identified etiology in a patient with HPE.

Cooperation of tumor-derived HBx mutants and p53-249(ser) mutant in regulating cell proliferation, anchorage-independent growth and aneuploidy in a telomerase-immortalized normal human hepatocyte-derived cell line.

Hepatocellular carcinoma (HCC) is a common cancer, and hepatitis B virus (HBV) is a major etiological agent. Convincing epidemiological and experimental evidence also links HCC to aflatoxin, a naturally occurring mycotoxin that produces a signature p53-249(ser) mutation. Recently, we have reported that tumor-derived HBx variants encoded by HBV exhibited attenuated transactivation and proapoptotic functions but retained their ability to block p53-mediated apoptosis.

Long-term persistence of nonpathogenic clonal chromosome abnormalities in donor hematopoietic cells after allogeneic stem cell transplantation.

We describe the cases of two unrelated patients who exhibited multiple chromosomal abnormalities in donor cells after allogeneic peripheral blood stem cell transplantation (PBSCT). The patients were diagnosed with chronic myeloid leukemia and chronic lymphocytic leukemia, respectively, and both underwent nonmyeloablative conditioning with cyclophosphamide and fludarabine followed by PBSCT from their HLA-matched opposite-sex siblings. Post-transplant bone marrow cytogenetics showed full engraftment, and the early post-transplant studies demonstrated only normal donor metaphases.

Statement on guidance for genetic counseling in advanced paternal age.

In 1996, a practice guideline on genetic counseling for advanced paternal age was published. The current document updates the state of knowledge of advanced paternal age effects on single gene mutations, chromosome anomalies, and complex traits.

Autosomal dominant congenital cataract in a Libyan Jewish family: cosegregation with a reciprocal chromosomal translocation [t(3;5)(p22.3; p15.1)].

Purpose: To describe a Jewish family of Libyan ancestry in which autosomal dominant congenital cataract segregates with an apparently balanced reciprocal chromosomal translocation.

Methods: Detailed family history and clinical data were recorded. Cytogenetic studies were performed on 13 family members.

MDA-MB-435 cells are derived from M14 melanoma cells--a loss for breast cancer, but a boon for melanoma research.

Background: The tissue of origin of the cell line MDA-MB-435 has been a matter of debate since analysis of DNA microarray data led Ross et al. (2000, Nat Genet 24(3):227-235) to suggest they might be of melanocyte origin due to their similarity to melanoma cell lines. We have previously shown that MDA-MB-435 cells maintained in multiple laboratories are of common origin to those used by Ross et al.

Factor VII deficiency and developmental abnormalities in a patient with partial monosomy of 13q and trisomy of 16p: case report and review of the literature.

Background: Unbalanced chromosomal translocations may present with a variety of clinical and laboratory findings and provide insight into the functions of genes on the involved chromosomal segments.

Case Presentation: A 9 year-old boy presented to our clinic with Factor VII deficiency, microcephaly, a seizure disorder, multiple midline abnormalities (agenesis of the corpus callosum, imperforate anus, bilateral optic nerve hypoplasia), developmental delay, hypopigmented macules, short 5th fingers, and sleep apnea due to enlarged tonsils. Cytogenetic and fluorescence in situ hybridization analyses revealed an unbalanced translocation involving the segment distal to 16p13 replacing the segment distal to 13q33 [46, XY, der(13)t(13;16)(q33;p13.

Constitutional trisomy 8 mosaicism due to meiosis II non-disjunction in a phenotypically normal woman with hematologic abnormalities.

Constitutional trisomy 8 mosaicism (CT8M) in liveborns is typically caused by mitotic non-disjunction and exhibits wide phenotypic variability. By contrast, CT8M due to meiotic errors usually results in miscarriage. We describe a case of CT8M due to a paternal meiosis II non-disjunction error.

Segregation of a t(1;3) translocation in multiple affected family members with both types of adjacent-1 segregants.

A subtle balanced translocation involving the terminal regions of 1q and 3p was identified in a large family by high-resolution karyotype analysis and confirmed by fluorescence in situ hybridization (FISH) analysis. In this family, segregation of a balanced t(1:3)(q42.3;p25) chromosome translocation led to two types of viable unbalanced complements.