Causes of Hypothyroidism: Congenital Causes
Posted on: June 11, 2006 | Posted in: Medical Information
Some people are born with hypothyroidism, for a variety of reasons. Infants with untreated congenital hypothyroidism can develop a number of serious developmental problems as they mature, including mental retardation and stunted growth—a condition once known as “cretinism” (think of that next time you want to call someone a “cretin”, eh? I don’t think I’ve used that particular insult in months, for just that reason!).
Some cases of congenital hypothyroidism seem to stem from developmental issues during pregnancy. The child’s thyroid gland may be underdeveloped or may no have descended to its proper location. In another condition, known as Thyroid Dyshormonogenesis, the infant’s thyroid gland simply fails to produce adequate hormone output, although it appears normal. In cases where the thyroid gland is abnormal, treatment will most likely last the rest of the child’s life.
Other cases of infant hypothyroidism seem to spontaneously resolve in a few weeks or months. Called “transient” hypothyroidism, this is sometimes caused by the mother’s treatment for Grave’s disease or hyperthyroidism during pregnancy. Women with any history of thyroid dysfunction have a higher chance of their children experiencing transient hypothyroidism at birth, however once the transient problem resolves, no further treatment is necessary.
In 2002, a new cause for congenital hypothyroidism was determined: mutations of the thyroid oxidase 2 (THOX2) gene(s). You inherit a copy of this gene from each of your parents. If only one gene is mutated, a child may have transient hypothyroidism at birth, which spontaneously resolves but may return later in life (particularly at times of high thyroid demand, such as pregnancy/childbirth, periods of extreme stress, etc.). If both THOX2 genes are mutated, it seems to cause more severe, non-transient hypothyroidism. THOX2 mutations may be responsible for previously “undefined” cases of congenital hypothyroidism, and possibly adult cases of non-autoimmune thyroid dysfunction.
Although rare (approximately 1 in 4000 infants suffers hypothyroidism), the side effects of infant hypothyroid problems are so severe—and so much important development goes on during infancy—getting treatment as soon as possible is of paramount importance. Because of the relation between a mother’s thyroid problems and congenital hypothyroidism, it is doubly important that hypothyroid women be familiar with the symptoms (from Mary Shomon’s book, “>Living Well with Hypothyroidism):
- Puffy face, swollen tongue
- Hoarse cry
- Cold extremities, mottled skin
- Low muscle tone (floppy, no strength)
- Poor feeding
- Thick coarse hair that goes low on the forehead
- Large fontanel (soft spot)
- Prolonged jaundice
- Herniated bellybutton
- Lethargic (lack of energy, sleeps most of the time, appears tired even when awake)
- Persistent constipation, bloated or full to the touch
- Little to no growth
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