Inherited syndrome with iris coloboma, ptosis,
hypertelorism, mental retardation, broad nasal bridge, and short stature.
Iris Coloboma, Ptosis, Hypertelorism, and Mental
Autosomal recessive inheritance. The disease
has been assigned to a pericentric inversion involving chromosome locus
The typical clinical picture aids in making the
diagnosis. Chromosomal studies may show the pericentric inversion on
Global developmental delay with lissencephaly,
pachygyria or polymicrogyria, and hypotonia are typical. Seizures have been
reported. Colobomata affect the iris but also may involve the retina and the
optic nerve. These may be the only features distinguishing this syndrome from
Noonan syndrome. Hypertelorism, ptosis, prominent epicanthic folds,
thickened, edematous eyelids, and heterochromia of the iris are further
ophthalmologic features. Broad nasal bridge, long philtrum, thin upper lip,
macrostomia, webbed neck, and short stature are other morphologic features.
Some patients present with ventricular septal defect.
The need for specific investigations
must be guided by the clinical scenario. If Noonan syndrome is considered,
echocardiography would be useful to exclude cardiac defects.
Developmental delay may affect the
ability of patients to cooperate. Although no reports describing anesthetic
management have been published, these patients should be considered to be at
risk for malignant hyperthermia because of the close relationship with
Inhalational anesthetics and
succinylcholine should be avoided because of possible malignant
hyperthermia. Neuromuscular blockers should be used with caution in the
presence of hypotonia.
Noonan Syndrome: Rare genetic disorder with phenotypical
similarity to Turner syndrome; however, the karyotype in Noonan syndrome is
King-Denborough Syndrome: Autosomal dominant transmitted
dysmorphic syndrome with susceptibility to malignant hyperthermia.
Baraitser M, Winter RM: Iris coloboma, ptosis, hypertelorism, and mental
retardation: A new syndrome. J Med Genet
Verloes A: Iris coloboma, ptosis, hypertelorism, and mental retardation:
Baraitser-Winter syndrome or Noonan syndrome? J Med Genet