Sotos Syndrome (cerebral gigantism) is one of the overgrowth syndromes. There is no diagnostic genetic or biochemical test, and phenotypic appearance is how the patients are identified.


Inheritance: Most cases are sporadic (so the parents will appear normal), but a small percentage of cases show autosomal dominant inheritance.


Features noted in infants:

(1) frontal bossing

(2) macrocephaly with dolichocephaly

(3) high-arched palate

(4) temporal narrowing giving the appearance of hypertelorism

(5) large size at birth, especially for length > +2 SD (rapid prenatal growth)


Features seen as the patient develops:

(1) high forehead

(2) downslanting palpebral fissues (antimongoloid slant; lateral canthus lower than medial)

(3) long face

(4) facial outline compared to an inverted pear

(5) facial flushing, with reddish coloration of cheeks, chin and nasal tip

(6) slow hair growth in the frontoparietal region

(7) excessive growth in early childhood, especially in the limbs

(8) advanced bone age for birth age

(9) prominent jaw


Other findings that may be identified:

(1) developmental delays and behavioral problems

(2) dental abnormalities

(3) foot deformities

(4) feeding difficulties in infancy with failure to thrive

(5) hypotonia and problems with coordination

(6) frequent upper respiratory tract infections


Differential diagnosis: Several overgrowth syndrome share physical characteristics, while not all patients with Sotos syndrome show classic findings. Thus phenotypic diagnosis may be uncertain and misdiagnosis does occur.


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