Gene behind freckles, brown hair and blue eyes found

November 23, 2013

boards.weddingbee.comWashington, Nov 23: In the study of Icelanders, researchers uncovered an intricate pathway involving the interspersed DNA sequence, or non-coding region, of a gene that is among a few dozen associated with human pigmentation traits.

It is more common to find people with ancestors from geographic locations farther from the equator, such as Iceland, who have less pigment in their skin, hair and eyes.

The researchers, including scientists from the National Human Genome Research Institute (NHGRI), analysed data from a genome-wide association study (GWAS) of 2,230 Icelanders.

A GWAS compares hundreds of thousands of common differences across individuals' DNA to see if any of those variants are associated with a known trait.

"This study explains a complex molecular pathway that may also contribute insights into skin diseases, such as melanoma, which is caused by the interaction of genetic susceptibility with environmental factors," said NHGRI Scientific Director Dan Kastner.

Researchers focused on the interferon regulatory factor 4 (IRF4) gene, previously associated with immunity. IRF4 makes a protein that spurs production of interferons, proteins that fight off viruses or harmful bacteria.

The researchers noted from genomic databases that the IRF4 gene is expressed at high levels only in lymphocytes, a type of white blood cell important in the immune system, and in melanocytes, specialized skin cells that make the pigment melanin. The new study established an association between the IRF4 gene and the pigmentation trait.

"Genome-wide association studies are uncovering many genomic variants that are associated with human traits and most of them are found in non-protein-coding regions of the genome," said William Pavan, co-author and senior investigator, Genetic Disease Research Branch, NHGRI.

The Icelandic GWAS yielded millions of variants among individuals in the study. The researchers narrowed their study to 16,280 variants located in the region around the IRF4 gene.

They used an automated fine-mapping process to explore the set of variants in IRF4 in 95,085 people from Iceland. The data revealed that a variant in a non-coding, enhancer region that regulates the IRF4 gene is associated with the combined trait of sunlight sensitivity, brown hair, blue eyes and freckles.

The study was reported in the journal Cell.

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May 17,2020

Geneva, May 17: Spraying disinfectant on the streets, as practised in some countries, does not eliminate the new coronavirus and even poses a health risk, the World Health Organization (WHO) warned on Saturday.

In a document on cleaning and disinfecting surfaces as part of the response to the virus, the WHO says spraying can be ineffective. "Spraying or fumigation of outdoor spaces, such as streets or marketplaces, is... not recommended to kill the Covid-19 virus or other pathogens because disinfectant is inactivated by dirt and debris," explains the WHO.

"Even in the absence of organic matter, chemical spraying is unlikely to adequately cover all surfaces for the duration of the required contact time needed to inactivate pathogens." The WHO said that streets and pavements are not considered as "reservoirs of infection" of Covid-19, adding that spraying disinfectants, even outside, can be "dangerous for human health".

The document also stresses that spraying individuals with disinfectants is "not recommended under any circumstances".

"This could be physically and psychologically harmful and would not reduce an infected person's ability to spread the virus through droplets or contact," said the document.

Spraying chlorine or other toxic chemicals on people can cause eye and skin irritation, bronchospasm and gastrointestinal effects, it adds.

The organisation is also warning against the systematic spraying and fumigating of disinfectants on to surfaces in indoor spaces, citing a study that has shown it to be ineffective outside direct spraying areas.

"If disinfectants are to be applied, this should be done with a cloth or wipe that has been soaked in disinfectant," it says.

The SARS-CoV-2 virus, the cause of the pandemic that has killed more than 300,000 people worldwide since its appearance in late December in China, can attach itself to surfaces and objects.

However, no precise information is currently available for the period during which the viruses remain infectious on the various surfaces.

Studies have shown that the virus can stay on several types of surfaces for several days. However, these maximum durations are only theoretical because they are recorded under laboratory conditions and should be "interpreted with caution" in the real-world environment.

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June 24,2020

New Delhi, Jun 24: Expanding the testing criterion for coronavirus, the Indian Council of Medical Research has said it should be made widely available to all symptomatic individuals across the country.

"Since test, track and treat' is the only way to prevent spread of infection and save lives, it is imperative that testing should be made widely available to all symptomatic individuals in every part of the country and contact tracing mechanisms for containment of infection are further strengthened," it said in an advisory on 'Newer Additional Strategies for COVID-19 Testing' on Tuesday.

In its revised testing strategy for COVID-19 issued on May 18, the Indian Council of Medical Research (ICMR) had advised testing for all symptomatic Influenza-like illness (ILI) among returnees and migrants within seven days of illness.

All hospitalised patients who develop ILI symptoms, symptomatic individuals living within hotspots or containment zones and healthcare and frontline workers involved in containment and mitigation of coronavirus were also advised testing.

The apex health research body has also advised authorities to enable all government and private hospitals, offices and public sector units to perform antibody-based COVID-19 testing for surveillance to help allay fears and anxiety of healthcare workers and office employees.

The earlier advisories on rapid antibody testing advisories had focused on areas reporting clusters (containment zones), large migration gatherings/evacuees centers and testing of symptomatic ILI individuals at facility level.

Besides, the ICMR on Tuesday also recommended deployment of rapid antigen detection tests for COVID-19 in combination with RT-PCR tests in all containment zones, all central and state government medical colleges and government hospitals, all private hospitals approved by the National Accreditation Board for Hospitals and Healthcare (NABH), all NABL-accredited and ICMR approved private labs, for COVID-19 testing.

All hospitals, laboratories and state governments intending to perform the point-of-care antigen tests need to register with ICMR to obtain the login credentials for data entry.

"ICMR advises all state governments, public and private institutions concerned to take required steps to scale up testing for COVID-19 by deploying combination of various tests as advised," the advisory added.

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May 25,2020

Singapore, May 25: COVID-19 patients are no longer infectious after 11 days of getting sick even though some may still test positive, according to a new study by infectious disease experts in Singapore.

A positive test "does not equate to infectiousness or viable virus," a joint research paper by Singapore's National Centre for Infectious Diseases and the Academy of Medicine, Singapore said. The virus "could not be isolated or cultured after day 11 of illness."

The paper was based on a study of 73 patents in the city-state.

The latest findings may have implications on the country's patient discharge policy. The discharge criteria is currently based on negative test results rather than infectiousness.

Singapore's strategy on managing COVID-19 patients is guided by the latest local and international clinical scientific evidence, and the Ministry of Health will evaluate if the latest evidence can be incorporated into its patient clinical management plan, according to a report by the Straits Times.

So far, 13,882, or about 45% of the total 31,068 Covid-19 patients in Singapore have been discharged from hospitals and community facilities. Singapore reported 642 new Covid-19 cases as of noon on Saturday.

The government has been actively screening pre-school staff as it prepares to reopen pre-schools from June 2. On Friday, two pre-school employees tested positive for the novel coronavirus, bringing the total number of confirmed cases among pre-school staff to seven, according to the Ministry of Health.

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