The classic triad consists of short neck,
restriction of neck movement, and low posterior hair line. Of these,
restriction of movement is most common and occurs in up to 50% of cases.
The syndrome often remains unrecognized because the neck may appear normal
and the patient is asymptomatic until later in life. Presentation may be
with neurologic deficit that occurs either spontaneously or after minor
trauma. Syncopal attacks may be precipitated by sudden rotary movements of
the neck. Other skeletal anomalies include cervical vertebral fusion,
hemivertebrae, sacral agenesis, scoliosis (either primary or secondary) in up to 60% of cases,
spinal canal stenosis, and
torticollis. Other findings include webbed neck, Sprengel deformity
(both, small and elevated scapula) in 30%, genitourinary abnormalities in
35 to 65% (hydronephrosis, renal ectopia, renal agenesis, horseshoe kidney, anomalies of the
collecting system),
congenital heart disease in 15% (particularly ventricular
septal defect), deafness in 30% (conductive and/or sensorineural), synkinesia (mirror movements) in 20%,
and, rarely, paraplegia or hemiplegia. Cleft palate is common, as is the
association with malformation of laryngeal cartilage and mild-to-severe
vocal cord paresis.