Thyroid Problem in Expecting Mothers Hampers Brain Development in Fetus
Proper functioning of thyroid hormones transporter in mother plays a crucial role in the development of brain in fetus.
A new study suggests that not only thyroid hormone is important for the development of the brain in fetus but transporters of these hormones are equally important. Improper functioning of the transporters may result in serious consequences in the development of the ‘the little brain’- cerebellum.
Thyroid hormones are usually associated with everyday metabolism but are very important even before birth. A fetus is dependent on mother’s hormones until the complete development of its own thyroid. So, insufficient hormone production in pregnant women may cause negative impact on the brain development of fetus.
These hormones check various cell types of brain stem during its development and move to its allocated place and make the correct connections.
Proper function of thyroid hormones is usually determined by measuring the level of hormones present in the blood. Although this technique is not a full proof indicator. The inadequacy of the technique was proved in the case of rare hereditary condition of nervous system, Allan-Herndon-Dudley syndrome (AHDS), only affecting boys.
Boys affected with this syndrome suffer from extreme mental retardation and locomotor deficits. When they were checked for hormonal deficiencies, doctors were surprised to see a very high level of hormones in them. The main problem was recognized in the transporters which carry the hormones inside the cell from blood. The reason was a genetic mutation of an important transporter “MCT8” which gets deactivated in AHDS patients.
On examining a chick embryo with deactivated transporter in the part of little brain. Researchers observed that the part of the brain which lacked an active transporter did not produce important proteins necessary for the development of the brain cells. Additionally, nerve cells in the cortex of the little brain known as Purkinje cells also had less dendritic branches. Therefore, brain cell signaling is completely disturbed and problems start originating in other parts of the cell as well.
If the things go wrong before birth, it becomes hard to repair it later. The findings from the study demonstrate the importance of thyroid hormones in the embryonic development right from the beginning. The study suggests that it is necessary to treat the mothers-to-be for thyroid problems as early as possible instead of the newborns.
Professor Veerle Darras said, “For the Allan-Herndon-Dudley syndrome, in particular, our study raises questions about possible prenatal treatments with variants of thyroid hormones: these can enter the cell without the transporter. But this is still an experimental treatment – one that is only being tested after birth”.
The study was performed by the researchers from KU Leuven (University of Leuven, Belgium) and King’s College, London.