RUBINSTEIN-TAYBI SYNDROME
DEFINITION:
A multiple congenital anomaly syndrome of unknown etiology
characterized by mental and growth retardation, short broad
thumbs and/or halluces, and typical facial features.
EPIDEMIOLOGY:
- incidence: rare (over 600 cases reported worldwide)
- age of onset:
- mean age of diagnosis is 15.2 months of age
- risk factors:
- sporadic occurence
- institutionalized patients (1/300 in Ontario)
- M = F
PATHOGENESIS:
- syndrome first described by Rubinstein and Taybi in 1963
although first report by Michail et al., in 1957 and thus
the name Broad Thumb-Hallux Syndrome (BTHS)
- review of BTHS in the American Journal of Medical
Genetics Supplement 6: 1-83 (1990)
2. Pathogenesis
- an in utero etiology has been proposed due to the
presence of characteristic facial anomalies at birth (upward
slanting of the palpebral fissures, abundant dark scalp
hair, facial hirsutism) and persistence of some fetal traits
(persistent fetal finger pads, shawl scrotum)
CLINICAL FEATURES:
- neonatal distress +/- recurrent respiratory tract
infections (78%)
- feeding difficulties (77%)
- constipation (54%)
- allergy (31%)
- birth weight 2.5 kg or less; polyhydramnios (20%)
2. Neurological Manifestations
- developmental delay (motor, language, social) - 99%
- IQ < 50 (most have IQ in mild-moderate range) - 74%
- hyperactive deep tendon reflexes (53%)
- seizures (28%)
- others: self-stimulating behaviour (rocking, spinning,
hand-flapping)
3. Facial Manifestations
- beaked or straight nose (93%)
- highly-arched palate (93%)
- downward-slanting palpebral fissures (90%)
- broad nasal bridge (86%)
- hypertelorism (83%)
- others: ear anomalies, nasal septum below alae, mild
retrognathia, grimicing smile, epicanthal folds, heavy or
highly-arched eyebrows, prominent forehead, long eyelashes,
small mouth, dental anomalies, facial asymmetry
- Note: the facial features evolve with age in a
characteristic manner
4. Musculoskeletal Manifestations
- broad, short thumbs and/or halluces (100%)
- microcephaly (head circumference <50th%) - 95%
- short stature (height <50th%) - 93%
- stiff gait (87%)
- broad terminal phalanges of other fingers (73%)
- others: vertebral anomalies (spina bifida, kyphosis,
lordosis, scoliosis), large or late-closing anterior
fontanelle, hypotonia, lax ligaments, hyperextensible
joints, sternal or rib anomalies, overlapping toes, 5th
finger clinodactyly, angulation deformity of thumbs with
abnormally- shaped proximal phalanx, high incidence of
fractures
5. Ophthalmologic Manifestations
- strabismus (71%)
- refractive error (56%)
- nasolacrimal duct obstruction (37%)
- ptosis (29%)
- others: colobomata, cataracts, intrauterine keratitis,
corneal leukoma, congenital corneal scar, glaucoma
6. Cutaneous Manifestations
- hirsutism (75%)
- capillary hemangiomata (flat) - 61%
- deep plantar crease between 1st & 2nd toes (56%)
- supernumerary nipples (16%)
- others: simian crease, keloid formation, cafe-au-lait
spots
7. Other Manifestations
- azygous lobe or other abnormal lobation
- laryngomalacia
2. Cardiovascular
- PDA, VSD, ASD, Coarctation of the Aorta
- cor pulmonale, conduction defects, cardiomyopathy
3. Genitourinary
- congenital anomalies, urinary tract infections,
nephrosis
- incomplete or delayed descent of the testes, small
angulated penis, hypospadias, shawl scrotum
INVESTIGATIONS:
- skull
- large foramen magnum, parietal foramina
- pelvic
- flat acetabular angles, flaring of ilia, notch in
ischia
2. CT/MRI
- absent/hypoplastic corpus callosum
3. EEG
- abnormalities in 66% of cases
MANAGEMENT:
- multidisciplinary approach
- Paediatrics, Cardiology, Orthopedics, Ophthalmology,
Dentistry, Surgery
- genetic counselling
2. Surgery
- orchidopexy for undescended testes
- surgical correction of angulated thumbs between 1-2
years of age with improved opposition and grasp
3. Prognosis
- normal life span
- group homes or supervised apartments when older
- sheltered workshops or supervised employment
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