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Inherited syndrome with iris coloboma, ptosis, hypertelorism, mental retardation, broad nasal bridge, and short stature.

Iris Coloboma, Ptosis, Hypertelorism, and Mental Retardation Syndrome.

Unknown, but very rare.

Autosomal recessive inheritance. The disease has been assigned to a pericentric inversion involving chromosome locus 2p12-q14.

The typical clinical picture aids in making the diagnosis. Chromosomal studies may show the pericentric inversion on chromosome 2.

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 Noonan syndrome.

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 normal.

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 25:41, 1988.  [PubMed: 3351890]
Verloes A: Iris coloboma, ptosis, hypertelorism, and mental retardation: Baraitser-Winter syndrome or Noonan syndrome? J Med Genet 30:425, 1993.  [PubMed: 8320709]

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