Archive for October, 2012

Genetic Diseases: new horizons, new hopes

Tuesday, October 23rd, 2012

Monogenic genetic diseases are frequent causes of neonatal morbidity and mortality, and disease presentations are often undiagnosed. Scientists have already identified genetic problems for more than 7,000 genetic diseases and around 500 of these already have applicable treatments. Thousands of disorders caused by a single gene defect have been characterized at molecular levels, but clinical testing is available for only some of them and many have clinical and genetic heterogeneity. Hence, unmet need exists for improved care and molecular diagnosis in infants. Because for some of these disorders the progression of the disease is extremely rapid, albeit heterogeneous, molecular diagnoses must occur quickly to be relevant for clinical decision-making. Fortunately, in the last three years, faster DNA sequencing machines or the so-called Next Generation Sequencing (NGS) together with improved data analysis tools have been able to facilitate the diagnosis of genetic disorders in days rather than weeks, and we can expect to do it in hours since technologies in this field are evolving fast. Whole genome sequencing, for example, can already identify new genetic defects, never seen or described before. Health care professionals can group children that have the same symptoms and genetic mutations, providing new clues on how to proceed to treat these patients. Armed with computer program searches for genes based on the baby’s symptoms, they can diagnose genetic diseases with more certainty (for more information see “Rapid Whole-Genome Sequencing for Genetic Disease Diagnosis in Neonatal Intensive Care Units” by Saunders et al.). This way, new genetic disorders can be identified combining DNA sequencing with bioinformatics and the symptoms or morphological defects of the children. Diagnosing unidentified diseases will add more information to the biomedical field and help pharmaceutical companies identify and test new drugs (see also “Rapid test pinpoints newborns’ genetic diseases in days” by Monya Baker). These tests could represent one of the first practical fruits of the revolution in sequencing an individual’s entire DNA (see the article “Infant DNA Tests Speed Diagnosis of Rare Diseases” by Gina Kolata in the NYTimes). This brings new market opportunities for genetic testing, biotechnology and pharmaceutical companies. Tests such as whole genome sequencing that reveals fatal genetic diseases could also improve genetic counseling by informing parents on their probabilities of having new children with the same defects. Most genetic diseases have no treatments yet; however, for the ones that are identified and there are treatments, this type of test will increase the chances for the babies to survive and avoid the problems caused by an undiagnosed condition. Whole genome sequencing still cannot diagnose all genetic diseases; however these new breakthroughs in medical genetics will enable a better diagnosis for many cases that would otherwise have remained harrowing mysteries. More research needs to be done before these tests make it to market and are covered by the healthcare system (it is still expensive, costing between 8,000-15,000 dollars), but these studies bring new hope for families of kids with genetic disorders. (Image Source: GEN News)