Mental retardation associated with myopathy, facial
malformation, and seizures.
Puerto Rican Infant Hypotonia Syndrome.
have been described; genetic inheritance unknown.
Features include myopathy, (congenital fiber type
disproportion, i.e., type I muscle fibers are significantly smaller than type II fibers
(normally about the same size), and a predominance of type I fibers by numbers
(normally about equal)), nonprogressive hypotonia, facial malformations (hypertelorism, broad nasal root,
long philtrum, mouth held open, high-arched and narrow palate, microdontia),
delayed bone age with abnormal ossification, pectus excavatum, seizures, and mental
Direct laryngoscopy and tracheal
intubation could be difficult because of facial malformations. Avoid
anesthetic muscle relaxants until the airway has been secured. Evaluate
neurological function (clinical, history, CT/MRI, EEG). Consider interaction
between antiepileptic treatment and anesthetic drugs. Evaluate myopathy
(history, clinical, creatine phosphokinase); avoid succinylcholine and
halogenated drugs. Reduce neuromuscular blocking agent doses because of
hypotonia and use a peripheral nerve stimulator.
Qazi QH, Markouizos D, Rao C, et al: A syndrome of hypotonia,
psychomotor retardation, seizures, delayed and dysharmonic skeletal
maturation, and congenital fibre type disproportion. J Med Genet 31(5):405, 1994.