Underweight babies, the cause is genetics

The CDKAL1 gene known to scientists as involved in the development of type 2 diabetes could also be the cause of low birth weight babies. The discovery was made by researchers at Children's Hospital of Philadelphia and the University of Pennsylvania School of Medicine and highlights an unusual condition; that in which the same gene is implicated both in a prenatal event and in one that occurs later in life such as type 2 diabetes. This diabetic form is due to the production of insufficient insulin by the pancreas or to the inability of the organism to use it correctly. It is caused by the interaction of environmental factors, such as poor diet, advancing age and lack of physical activity, and by a genetic predisposition. Previous research, in fact, has shown that there are at least 20 gene variants that predispose to type 2 diabetes. In the new study, the scientists used data collected by the genome-wide association during a study on childhood obesity to select 5,465 Caucasian babies with the lowest birth weight. They then looked for which of the 20 gene variants were present in them, discovering a strong association between an allele of the CDKAL1 gene and low weight. The result therefore supports what is called the fetal insulin hypothesis, according to which a low production of insulin during prenatal life can cause the birth of children smaller than normal, as it acts as an important growth factor, i.e. as a a substance capable of stimulating the division and growth of cells. The mechanism by which the CDKAL1 gene acts has not yet been clarified but it probably causes a reduced secretion of insulin by the pancreas, predisposing to diabetes and poor growth of the fetus. From: Examination of type 2 diabetes loci implicates CDKAL1 as a birth weight gene. Zhao J, Li M, Bradfield JP, Wang K, Zhang H, Sleiman P, Kim CE, Annaiah K, Glaberson W, Glessner JT, Otieno GF, Thomas KA, Garris M, Hou C, Frackelton EC, Chiavacci RM, Berkowitz RI , Hakonarson H, Grant SF. Diabetes. 2009 Jul 10.