Down syndrome, Turner syndrome, and Klinefelter syndrome: primary care throughout the life span.

Down syndrome, Turner syndrome, and Klinefelter syndrome constitute the most common chromosomal abnormalities encountered by primary care physicians. Down syndrome typically is recognized at birth, Turner syndrome often is not recognized until adolescence,and many men with Klinefelter syndrome are never diagnosed. Although each syndrome is caused by an abnormal number of chromosomes, or aneuploidy, they are distinct syndromes with learning disabilities and a predisposition toward autoimmune diseases,endocrinologic disorders, and cancers. Optimal health care requires a thorough knowledge of the unique health risks, psychoeducational needs, functional capabilities, and phenotypic variation associated with each condition. Syndrome-specific health care should complement standard preventive health care recommendations. Checklists and syndrome-specific growth grids should be used. Ongoing communication between specialists and primary care physicians and between pediatric and adult clinicians is essential. Support groups and Internet resources can benefit affected individuals and their families immensely.