According to a study, researchers claim to have discovered a genetic link for extreme thinness. It is the research that shows that people with extra copies of certain genes are much more likely to be very skinny. In them, the part of chromosome 16 is duplicated, which makes men 23 times and women five times more likely to be underweight.
Usually every person has a set of the chromosome from each parent, so we have two copies of each gene. But sometimes parts of a chromosome is deleted or duplicated. It results in an abnormal ‘dosage’ of genes. When the DNA of over 95,000 people, researchers have identified that duplication of a part of chromosome 16 is associated with being underweight, defined as a body mass index below 18.5. Half of all children with the duplication in the study have been diagnosed with a ‘failure to thrive’, which means that their rate of weight gain is significantly lower than average. A quarter of people with the duplication have microcephaly, a condition in which the head and brain are abnormally small, which is associated with neurological defects and shorter life expectancy.
The genome is full of holes where genes are lost, and we have extra copies of genes in other places. In many cases, deletions and duplications do not affect, but sometimes they can lead to disease.
Scientists have discovered a large number of genetic changes that lead to obesity. It seems that we have plenty of systems that increase appetite since eating is so important. This is the first genetic cause of extreme thinness that has been identified.
The important thing is that it shows that failure to thrive in childhood can be genetically driven. If a child is not eating, it’s not necessarily the parents’ fault.
It is also an example of deletion and duplication of one part of the genome having opposite effects. Scientists are working on why the gene duplication in this region causes thinness. It might throw new potential treatments for obesity and appetite disorders.
The part of chromosome 16 identified in the study contains 28 genes. Duplications in this region have also been linked with autism and schizophrenia.