Category Archives: Transhuman News

Public release date: 8-Nov-2012 [ | E-mail | Share ]

Contact: Cathy Yarbrough press@ashg.org 858-243-1814 American Society of Human Genetics

A consortium of scientists who are taking a novel approach in their research to detect the genetic variations that predispose individuals to type 2 diabetes provided an update of their findings at the American Society of Human Genetics (ASHG) 2012 meeting.

Among the project's novel characteristics is the ethnic diversity of the 10,000 individuals whose exomes, the 18,000 protein-coding genes, are being sequenced.

The researchers recruited 5,000 individuals with type 2 diabetes (T2D) from five major ancestry groups: African-American, East Asian, European, Hispanic and South Asian. The study population also includes an equal number of controls, individuals from these same ancestry groups who do not have T2D.

"Our hypothesis is that screening the exome in a range of diverse ethnic groups increases the range of variants of each gene surveyed, and thereby improves our ability to detect genes showing differences in the patterns of the DNA codes for proteins between individuals with type 2 diabetes and controls," said T.M. Teslovich, Ph.D., research fellow in statistical genetics at the University of Michigan, who presented the study at ASHG 2012.

The study is one of the three projects under the umbrella of the NIH-sponsored T2D-GENES (Type 2 Diabetes Genetic Exploration by Next-generation sequencing in multi-Ethnic Samples) study.

The scientists' approach also will enable them to determine whether there are T2D risk variants that are unique to an ancestry group.

An initial analysis of the data on 3,500 African-American, East Asian and South Asian individuals identified about 1.6 million single nucleotide variants (SNVs), 71.5% of which were previously unknown.

"Only about 89,000, or 5.6%, of the 1.6 million variants are present in all three groups," said Dr. Teslovich.

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Novel type 2 diabetes genetic study involves 5 major ancestry groups

Public release date: 8-Nov-2012 [ | E-mail | Share ]

Contact: Cathy Yarbrough press@ashg.org 858-243-1814 American Society of Human Genetics

Research findings confirming that de novo mutations represent a major cause of previously unexplained intellectual disability were presented on Nov. 8 at the American Society of Human Genetics 2012 meeting in San Francisco.

Josep de Ligt, M.Sc., bioinformatician and Ph.D. student in human genetics at Radboud University Nijmegen Medical Centre in The Netherlands, also reported findings lending support to the use of exome sequencing, which deciphers over 21,000 protein-coding genes and not the entire human genome, as a diagnostic assay to determine whether one or more genetic mutations explain a patient's intellectual disability.

The cause of intellectual disability, which represents a wide range of phenotypes, or observable biological characteristics, is unknown in at least 50% of patients.

Most individuals with intellectual disability without a known cause are the only members of their families with the condition. Because the cause of their child's cognitive impairment is unknown, parents are often baffled.

The child with a cognitive disability is often an "isolated case without family history of the condition," said de Ligt, adding that intellectual disability occurs in about 1% of the population,

By exome sequencing of 100 patients with unexplained cognitive impairment, de Ligt and his colleagues uncovered 79 genes with unique de novo mutations.

These de novo mutations were present in the DNA of the patients but not in that of their parents whose exomes also were sequenced.

"All de novo as well as X-linked mutations identified in this study were interpreted in the context of the clinical diagnosis," de Ligt pointed out.

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Exome sequencing: Potential diagnostic assay for unexplained intellectual disability