Rubinstein
Taybi SyndromeThis syndrome only with a frequency of 1 in 300,000 births,
but is fairly commonly seen (1 in 600) in mental retardation clinics. The typical features are broad malformed thumbs
and big toes as well as typical facial abnormalities and mental retardation. It
is due to a spontaneous deletion of part of chromosome
16(16p13-)leading to these multiple abnormal fetal developments. Signs
and symptoms Facial deformities include an underdeveloped small
maxilla with a narrow palate. Typically there are low set ears and often malformed.
Sometimes there is a typical talon cusp malformation in one or more incisor teeth
as depicted in this image. This person
shown in the link had only minimal features of Rubinstein Taybi syndrome,
but the typical dental abnormality triggered a chromosomal work-up and confirmed
the presence of this syndrome in this case. There are deformities
of thumb and big toe with a wide base and angulations towards the fingers
or toes. Syndactyly and polydactyly also exists in some cases. Several eye deformities
are also common like congenital glaucoma, retinal abnormalities and strabismus.
The child has growth retardation and as adults they do not grow taller
than 58 to 60 inches. The child has speech difficulties and a muscle weakness
problem (hypotonia). There are feeding problems. In girls hirsutism is common,
in boys cryptorchidism. Mental retardation is severe with an intelligence quotient
between 30 and 80, with 50% or more having an IQ of 50. Joint hypermobility poses
problems with patellofemoral instability and frequent patellar dislocations. Cardiac
malformations are common with ventricular septal defects, atrial septal defects,
patent ductus arteriosus etc. There is a high sensitivity to succinylcholine,
which is used generally with intubation general anesthesia during surgeries and
this can cause life threatening cardiac arrhythmias. Prognosis The prognosis depends on the
mix of congenital conditions present. Attention to detail by the cardiologist,
neurologist, pediatrician, orthopedic surgeon and ophthalmologist will give the
baby the best chance of survival. However, the limiting conditions are any cardiac
malformation, feeding problems with possible aspiration pneumonia and subsequent
infection and possible blindness, if the congenital eye abnormality is serious. |
