What causes congenital hypothyroidism?
The most common cause of congenital hypothyroidism is the incorrect growth of the thyroid gland. Early in fetal development, a baby’s thyroid gland begins to form in the brain and then moves to the neck. In some cases this process is interrupted, resulting in a small thyroid gland (dysgenesis) or even the lack of a thyroid gland (agenesis). This is a permanent condition that a baby does not outgrow. Congenital hypothyroidism does not appear to have a clear pattern of inheritance. There are some types of inherited hypothyroidism that are autosomal recessive. Most often, the parents of a child with an autosomal recessive condition are not affected because they are “carriers”, with one copy of an altered gene and one copy of the normal gene. Your endocrinologist and/or regional genetic center will let you know if your baby has this type of hypothyroidism and the chance of having another child with this condition.
