Hennekam developed an algorithm for the molecular diagnosis of Rubinstein-Taybi syndrome (RSTS). Many cases are associated with mutations in CREB binding protein (CRB), which functions as a suppressor to the cell cycle.


Patient selection: clinical features suggestive of RTS


Diagnostic testing:

(1) First perform FISH to detect microdeletions at 16p13.3 using 5 probes (RT100, RT102, RT166, RT191, RT203)

(2) If #1 negative, then perform mutation analysis at CBP on 16p13.3

(3) If #2 negative, then perform mutation analysis at p300 on 22q13.2


If any of the molecular tests is positive (55% of cases), then the diagnosis is confirmed. If none of the tests is positive (45%), then diagnosis depends solely on clinical features.


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