High variability in the expression of the
syndrome. Facial features consist of microcephaly with a round, flat
profiled face, early closure of the fontanelles, micrognathia, cleft palate,
depressed nasal bridge, short neck, glaucoma, proptosis, and blue sclerae.
Orthopedic anomalies are micromelic dwarfism, scoliosis, and abnormal joint
laxity resulting in recurrent luxations of hip and patella. Infants may show
some distinctive additional skeletal signs, which may disappear after the
first year of life and include coronal clefts in thoracolumbar vertebrae,
and extra ossification centers, most often in the area of the
metacarpophalangeal joint of the index finger, resulting in supernumerary
phalanges and deviation of the fingers. The chest appears narrow and
“funnel” shaped, and the abdominal wall is hypoplastic. These children are
mentally retarded and approximately one third of them die in early infancy,
most commonly as a result of respiratory infections. Some also suffer from
obstructive sleep apnea syndrome. Ventricular septal defect, tracheomalacia,
and laryngomalacia have been reported, with the latter two findings
requiring tracheotomy in at least one patient. Long-term problems of these
children include worsening joint problems, chest and spine deformities,
recurrent aspiration pneumonias, and progressive psychomotor developmental
delay.