MCT8-specific thyroid hormone cell transporter deficiency
National Organization for Rare Disorders, Inc.
It is possible that the main title of the report MCT8-specific thyroid hormone cell transporter deficiency is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.
- MCT8-THCT deficiency
- Allan-Herndon-Dudley syndrome
- Allan-Herndon syndrome
- mental retardation, X-linked, with hypotonia
- THCT deficiency
MCT8-specific thyroid hormone cell transporter deficiency (THCT deficiency) is an inherited disorder that is characterized by severe mental retardation, an impaired ability to speak, diminished muscle tone (hypotonia), and/or movement abnormalities.
With the exception of poor muscle tone, most affected infants appear to develop normally during the first months of life. However, by about two months of age, affected infants may seem weak and have an inability to hold up the head. Due to hypotonia, severely reduced motor development, and other abnormalities, affected children very rarely develop any ability to walk and when they do, it is with shuffling gait. Associated features often include underdevelopment (hypoplasia) and wasting (atrophy) of muscle tissue; weakness and stiffness of the legs (spastic paraplegia) with exaggerated reflexes (hyperreflexia); relatively slow, involuntary, purposeless, commonly dyskinetic (abnormal movement) attacks. Writhing movements (athetoid movements); and/or other movement abnormalities are less common. Affected individuals may also have abnormalities of the skull and facial (craniofacial) region. THCT deficiency is an inherited as an X-linked genetic disorder.
WE MOVE (Worldwide Education and Awareness for Movement Disorders)
204 West 84th Street
New York, NY 10024
Arc (a national organization on mental retardation)
1010 Wayne Ave
Silver Spring, MD 20910
NIH/Nat'l Institute on Deafness & Other Communication Disorders Information Clearinghouse
1 Communication Ave
Bethesda, MD 20892-3456
Thyroid Society for Education & Research
7515 S. Main
Houston, TX 77030
MUMS National Parent-to-Parent Network
150 Custer Court
Green Bay, WI 54301-1243
Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
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