Sotossyndrome, or cerebralgigantism, cerebralgigantismsyndromeinchildhood, also known as childhood giant brain syndrome ( macrencephalysyndrome, Sotos syndrome, is a syndrome in which the skeletal development grows too fast, the head is huge, and the intellectual development is delayed during infancy and school-age children. How is pediatric macrocephaly syndrome diagnosed? The syndrome is characterized clinically by significant growth of the body in the neonatal period, with long head and giant brain, mental retardation, idiosyncratic facial features and abnormal limb morphology. The birth weight and length of the child are greater than normal, and the growth is rapid during the first 4-5 years of life, then the growth seems to approach normal and stable, but the measured value is still more than two standard deviations from the mean value at the same age. The child may have a giant skull, long head, distant eye spacing, congenital dullness, peculiar facial features, prominent jaw, high palatal arch, mental retardation, clumsy movements or ataxia. Sometimes there may be obesity, twitching, abnormal hand skin pattern (increased number of total finger ridges between triangle a-b, large interfoveal lines and fingerprints with bucket-shaped lines are common), but abnormal skin texture has also been reported. Chromosomal examination was normal, fasting serum growth hormone concentration was normal, secretion stimulation test was also normal, oral glucose tolerance test could be abnormal in some cases, blood 17–ketosteroids were increased and 17–hydroxy corticosteroids were normal. Pneumoencephalography was done with varying degrees of ventricular dilatation, mainly lateral ventricle and third ventricle and brain parenchyma atrophy, and EEG had abnormalities. The diagnosis was confirmed based on the clinical features and laboratory and ancillary tests, and a positive family history facilitated the diagnosis of the syndrome. The etiology of this syndrome is unknown, but it may be due to pathological factors in utero or to the impaired function of the hypothalamic-pituitary axis. It has been suggested that this syndrome is familial and dominantly inherited, with a higher incidence in males than in females (4:1 or 3:1), so it is usually considered as X-linked inheritance.