Genetics of Rubinstein-Taybi Syndrome Clinical Presentation

Updated: Sep 19, 2018
  • Author: Keith K Vaux, MD; Chief Editor: Luis O Rohena, MD, MS, FAAP, FACMG  more...
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Presentation

Physical

Patients show multiple congenital anomalies, including intellectual disabilities, growth deficiency (postnatal), microcephaly, broad thumbs and first toes, and dysmorphic facial features. Patients have a striking facial appearance, characterized by highly arched eyebrows, long eyelashes, abnormally slanting palpebral fissures, broad nasal bridge, beaked nose, and mandibular abnormalities, including mild micrognathia. [11, 12, 3]

Selected physical findings

Facial abnormalities

These include the following:

  • Abnormal maxilla with narrow palate

  • Prominent beaked nose

  • Down-slanting palpebral fissures

  • Low-set and/or malformed ears

  • Strabismus 

  • Large anterior fontanel 

  • Microcephaly 

  • Malpositioned or crowded teeth, high palate, short upper lip, and protuberant lower lip are also seen

Digit abnormalities

These include the following:

  • Broad great toes

  • Broad thumbs with radial angulation

  • Broadness of other fingers

  • Persistent fetal finger pads

  • Syndactyly and polydactyly

Abnormalities of growth and development

These include the following:

  • Mental retardation with intelligence quotient (IQ) of 30-79 (average 51) - More than 50% of patients have an IQ of less than 50

  • Speech difficulty

  • Hypotonia

  • Electroencephalographic abnormalities (even in the absence of seizures)

  • Growth retardation (postnatal-onset growth deficiency; Rubinstein-Taybi syndrome [RTST]–specific charts are available) - Average male height: 153 cm; average female height: 147 cm

  • Feeding problems - Gastroesophageal reflux

Skeletal abnormalities

These include the following:

  • Retarded osseous maturation

  • Vertebral and sternal abnormalities

  • Patellar dislocation

Cardiac anomalies

These include the following:

Other symptoms and findings

These include the following:

  • Cryptorchidism (very common in males)

  • Hirsutism

  • Keloid formation

  • Cardiac arrhythmias

  • Laryngeal wall collapsibility

  • Sleep and anesthesia problems

In a study by Ajmone et al of 23 patients with RSTS, brain magnetic resonance imaging (MRI) revealed that 73.6% of the cohort had dysmorphia of the corpus callosum, with or without the presence of other anomalies, such as minor dysmorphia of the cerebellar vermis and hyperintensity of the posterior periventricular white matter. In addition, whole-spine MRI scans indicated a greater tendency for patients with RSTS to have a low-lying conus medullaris without thickening of the filum terminale. [13]