Rubinstein-Taybi Syndrome (RTS) [Q87.2]
OMIM number: 180849
Dr. med. Imma Rost
The Rubinstein-Taybi syndrome (RTS) is accompanied by intellectual disability as well as characteristic physical features. Frequency is estimated to be 1:125,000. Physical features are microcephaly, growth delay, down-slanting palpebral fissures, convex nasal ridge and low hanging columella. Nearly all patients have broad thumbs and big toes, sometimes accompanied by varus or valgus deformity. RTS usually occurs sporadically; there are only a few cases with autosomal dominant inheritance reported in the literature where the affected children were always more severely affected than their mothers from which the mutation was inherited.
In approx. 40% of all cases, RTS is caused by mutations in the CREBBP gene in the chromosomal region 16p13.3. Another 10% are due to microdeletions in this region. A small part (approx. 3%) is caused by mutations in the EP300 gene on the long arm of chromosome 22 (22q13.2), however, the degree of severity seems to be milder in these cases.