Pendred Syndrome
What is Pendred syndrome?
Pendred syndrome is an inherited syndrome which consists of deafness from the time of birth and enlargement of the thyroid gland (goiter) in the front of the neck. Pendred syndrome is a result of a defect in the production of the thyroid hormone, an essential hormone for normal body metabolism.
Thyroid hormones are produced by the thyroid gland. This gland is located in the lower part of the neck, below the Adam's
apple. It is
wrapped around the windpipe (trachea) and has the shape of a
butterfly which is formed by two wings (lobes) and attached by a middle
segment
(isthmus). Thyroid hormones are essential for the
function of
every cell in the body. They help regulate growth and the rate
of chemical
reactions (metabolism) in the body.
The features of Pendred syndrome are:
- Inner ear: Deafness at birth; defect in balance (vestibular function); and malformation of a portion of the inner ear (cochlea);
- Hormonal: Normal blood level of thyroid hormones due to compensated hypothyroidism;
- Neck: Swelling in the front of the neck (goiter);
- Intelligence: Mental retardation (due to the congenital thyroid defect);
- Cancer risk : Possible increased risk of thyroid cancer (thyroid carcinoma);
- Laboratory : Evidence for defect in the making of thyroid hormone (defect in incorporating iodine into the thyroid hormone, called an organification defect); and
- Inheritance: Inherited as an autosomal recessive condition (not linked to a sex chromosone). This means that both seemingly normal parents carry a copy of the Pendred syndrome gene and each of their children has a 1 in 4 (25%) chance of inheriting both parental Pendred syndrome genes and suffering from the syndrome.
Pendred syndrome was clinically recognized and concisely described in 1896 by the English general practitioner Vaughan Pendred (1869-1946). Exactly a century later, the gene for Pendred syndrome was discovered (by Coyle and Sheffield and colleagues) to be on chromosome 7q.
Pendred syndrome is also known as deafness with goiter, the goiter-deafness syndrome, and thyroid hormone organification defect IIb or the genetic defect in thyroid organogenesis IIb.
Pendred Syndrome At A Glance
- Pendred syndrome is an inherited syndrome which consists of deafness from the time of birth and enlargement of the thyroid gland (goiter).
- Pendred syndrome is a cause of mental retardation.
- It is inherited as an autosomal recessive condition.
Last Editorial Review: 4/30/2002
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