Rare diseases are genetic in nature and genome sequencing has the ability to help the patients in a way that conventional diagnostic tools cannot. MeghaGen customizes the genomics sequencing to the needs of the treating physician.
There are between 5,000 and 8,000 known rare diseases. 1 in 17 people, or 7% of the population, will be affected by a rare disease at some point in their lives. Most rare diseases have a genetic component. In about 80% of rare diseases, changes to DNA are involved in the cause.
DNA contains the instructions for making the proteins our bodies are built of – from the keratin in hair and fingernails to the antibody proteins that fight infection. A change to DNA means a change to proteins; it could be how the protein is built, or the amount of it that is made. Sometimes a change means that a protein doesn’t work properly. It could work too slowly, too quickly or not in the right way. If the protein is found in lots of areas of the body, then it could cause lots of different problems. These changes can have severe health impact on affected patients and their families, including physical and intellectual disabilities and premature death. Examples of rare diseases include Huntington disease, fragile X syndrome, Guillain-Barré syndrome, Crohn disease, and Duchenne muscular dystrophy. In addition, the economic impact of rare diseases is substantial not only for affected patients and their families, but for society as a whole.
Genome sequencing has been increasingly applied in the work-up of patients with rare and undiagnosed diseases, both in the United States and elsewhere. In fact, we have seen a rapid emergence of sequencing in clinical research in the past few years. This technology has provided success in identifying new causal mutations for rare suspected genetic diseases of previously unknown cause, with diagnostic rates of 25%-50% in recent studies. In addition, over the past 4 years, the NIH funded Centers for Mendelian Genomics have conducted sequencing and analysis of protein-coding portions of more than 20,000 human genomes and have identified over 740 genes that likely cause genetic diseases.
Molecular genomic diagnosis of rare diseases can lead to changes in medical care including use of existing medications or development of new ones to help people with specific mutations, as well as discontinuing ineffective therapies. One example for genomic study benefits is switching to high-fat diet in early infantile epileptic encephalopathy type 11, a severe, genetic form of epilepsy that is amenable to treatment with a ketogenic diet reduces the frequency of the seizures. Molecular insights have not led to effective therapies for most rare diseases so far, but they do promise deeper understanding into the biology of these conditions that could lead to better management and improved outcomes in the future. For an increasing number of rare diseases, treatments are becoming readily available, which can ameliorate or reduce the burden of illness and delay death. Examples include cystic fibrosis, hemophilia, sickle cell disease and phenylketonuria. Obviously, these are the early days of the application of whole genome sequencing in rare disease research and management and many scientific, ethical and societal challenges remain.