HUT (Hutterite)

Inheritance: autosomal recessive
Genes: SLC5A5

Congenital hypothyroidism
Iodine accumulation
Iodine transport defect

Hypothyroidism
Failure to thrive
Constipation
Mental retardation

Thyroid Hormone Dysgenesis 1

Clinical Characteristics

General description (for patients):  

The mutation causing this disease is responsible for low levels of thyroid hormone.  Infants and young children are lethargic, feed poorly and generally are slow developmentally.  They may appear chubby and have large tongues.  Constipation is an important sign.  It is important that the diagnosis and treatment with thyroid hormones take place early to prevent permanent brain damage.

Medical description:  

Several forms of hormone dysgenesis have been found in plain people (see also 274500).  This disorder is secondary to a defect in an iodine transporter mechanism and causes the classical findings of congenital hypothyroidism.

Genetics:

This defect in iodine transport causes an autosomal recessive condition in which the thyroid is unable to maintain the required iodine concentration in the thyroid gland.  This defect can also be demonstrated in the salivary gland and the gastric mucosa.  A mutation in the sodium-iodide symporter gene (SLC5A5) located on chromosome 19 (19p13.2-p12) seems to be responsible.  In a large consanguineous Hutterite kindred, a base substitution (1350G>A) was identified in this gene complex.

Treatment:

Thyroid replacement therapy

Prognosis:

Dependent upon age of treatment initiation.

Ancillary treatments and support:

Generally none needed if diagnosis made early and treatment initiated.

Specialists and specialty centers:

Endocrinologist, Pediatrician

References:

Park, S.M., and Chatterjee, V. K.K.:  Genetics of congenital hypothyroidism.  J. Med. Genet. 42: 379-389, 2005.  PubMed ID: 15863666

Couch, R.M., Dean, H.J., and Winter, J.S.:  Congenital hypothyroidism caused by defective iodide transport.  J. Pediatr.106: 950-953, 1985.  PubMed ID: 3998954

Kosugi, S., Bhayana, S., and Dean, H.J.:  A novel mutation in the sodium/iodide symporter gene in the largest family with iodide transport defect.  J. Clin. Endocrinol. Metab. 84: 3248-3253, 1999.  PubMed ID: 10487695

Resources:

Medline Plus thyroid disease
The Hormone Foundation
Endocrine Web

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