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Rett Syndrome (
MIM: 312750)
Rett
syndrome is a neurodevelopmental disorder that occurs almost exclusively
in females. Rett syndrome (RTT) is caused by mutation in the gene encoding
methyl-CpG-binding protein-2 (MECP2). It affects the development of the
central nervous system (grey matter). The
clinical features include small hands and feet and a deceleration of the rate
of head growth (including microcephaly in some), repetitive hand movements
(such as mouthing or wringing). Girls with Rett syndrome are prone to
gastrointestinal disorders and up to 80% have seizures.
Rett syndrome is usually sporadic, caused (95% or more) by a de novo mutation in
the child.
Peutz-Jeghers syndrome (
MIM: 175200
)
The
autosomal dominant Peutz–Jeghers syndrome, also known as hereditary
intestinal polyposis syndrome, is characterized by the development of benign
hamartomatous polyps in the gastrointestinal tract and
hyperpigmented macules on the lips and oral mucosa. The disease is
caused
due to mutations in the serine/threonine kinase STK11 gene. Peutz-Jegher
syndrome has a prevalence of approximately 1 in 25,000 to 300,000 births.
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