Clinical Characteristics

SMS clinical features:

•    Craniofacial anomalies:
o    Brachycephaly
o    Relative prognathism with age
o    Broad, square-shaped face
o    Everted, “tented” vermilion of the upper lip
o    Deep-set, close-spaced eyes.
o    Dental anomalies (missing premolars; taurodontism)

•    Otolaryngological problems:
o    Hearing loss, increasing loss with age
o    Hoarse, deep voice
o    Hyperacusis
o    Middle-ear and laryngeal anomalies
o    Frequent ear infections

•    Neurological features:
o    Infantile hypotonia
o    Oral sensorimotor dysfunction (early childhood)
o    Sensory processing issues
o    Developmental delay/ cognitive impairment
o    Speech/language impairment
o    Sleep disturbance
o    Inverted circadian rhythm of melatonin
o    Attention seeking behaviors
o    Tantrums, behavior dysregulation
o    Impulsivity
o    Stereotypic behaviors
o    Signs of peripheral neuropathy.

•    Skeletal anomalies:
o    Height less than expected based upon parental heights
o    Scoliosis
o    Short broad hands, short fingers