This book provides comprehensive details on a number of well-defined genetic disorders and a selection of less well-defined entities that include somatic overgrowth as a major manifestation. In addition to overgrowth, these syndromes each have their own distinguishing characteristics that benefit the clinician in making a specific diagnosis. In most cases, the causative genes are known, giving a means of laboratory confirmation of the diagnoses. A major distinction from other hereditary syndromes is a predisposition of patients with the overgrowth syndromes to develop neoplasms during childhood. In some cases, the overgrowth seems to be limited, even to the extent that some growth parameters may return to the normal range by adulthood. In other cases, the overgrowth is notable throughout life. In recent years, both the generalized and the segmental overgrowth syndromes have begun to yield their secrets to molecular technologies. These studies have provided clinicians a way to confirm the specific diagnosis so they can provide appropriate counseling and anticipatory management. In the case of segmental overgrowth disorders, they have also established their mosaic nature, which explains the sporadic occurrence and marked phenotype variability.
Clinical pitfalls in the diagnosis of segmental overgrowth syndromes: a child with the c.2740G > A mutation in PIK3CA gene