Down syndrome in a population of elderly mentally retarded patients: Genetic-diagnostic survey and implications for medical care

Ninety-six adults with Down syndrome (DS) from an institutional setting of 591 mentally retarded were investigated systematically with respect to cyto genetic diagnosis, mental functioning and dementia, ophthalmological and au diological abnormalities, and thyroid function. Seventy of the 96 DS patien ts (73%) were older than 40 years. Only 4.2% were females. Trisomy 21 was f ound in 86% and mosaic trisomy 21 in 13%. Eighty-two percent of the patient s were moderately or severely mentally retarded, 15% were profoundly retard ed, and only 3% mildly retarded. Nineteen percent of the patients had demen tia. This number increased to 42% of the patients above the age of 50 years . Epileptic seizures were present in 16.7% of all patients, and in 50% of t he patients with dementia. Only 17% of the patients in the present study ha d normal visual acuity, one-third had at least moderately reduced vision. T his number increased significantly with age: in the age group 50-59 years a lmost half of the patients had moderate to severe vision loss. Seventy perc ent of the patients had moderate, severe, or very severe hearing loss, whic h was undiagnosed before systematic hearing testing was performed. Increase d (48%) or decreased (1%) TSH level was found in 49% of the patients examin ed for thyroid functions. We suggest a regular screening of all adults with DS to diagnose early dementia, epilepsy, hypothyroidism, and early loss of visual acuity and hearing, with special attention to the group of patients who are severely to profoundly mentally retarded and Obese with advanced a ge. Cytogenetic studies are necessary to confirm the clinical diagnosis and are essential for genetic counseling purposes. (C) 1999 Wiley-Liss, Inc.