The genetic architecture of Down syndrome phenotypes revealed by high-resolution analysis of human segmental trisomies.

Down syndrome (DS), or trisomy 21, is a common disorder associated with several complex clinical phenotypes. Although several hypotheses have been put forward, it is unclear as to whether particular gene loci on chromosome 21 (HSA21) are sufficient to cause DS and its associated features. Here we present a high-resolution genetic map of DS phenotypes based on an analysis of 30 subjects carrying rare segmental trisomies of various regions of HSA21.

Voice parameters in children with Down syndrome.

Down syndrome (DS) is the most frequent chromosomal disorder. Commonly, individuals with DS have difficulties with speech and show an unusual quality in the voice. Their phenotypic characteristics include general hypotonia and maxillary hypoplasia with relative macroglossia, and these contribute to particular acoustic alterations.

The effect of acetyl-L-carnitine administration on persons with Down syndrome.

Since previous investigations reported improvements in cognition of patients with dementia after acetyl-L-carnitine therapy and since there is an increased risk for persons with Down syndrome to develop Alzheimer disease, this study was designed to investigate the effect of acetyl-L-carnitine administration on neurological, intellectual, and social functions in adults with Down syndrome. In this double-blind study we enrolled 40 individuals with Down syndrome and administered acetyl-L-carnitine to the study group during a six months period. Specified examinations and psychological tests were given to persons in both the study and control groups at the start of the investigation and at 3, 6, and 9 months.

Markers of oxidative stress in children with Down syndrome.

Background: Persons with Down syndrome have increased vulnerability to oxidative stress caused by overexpression of superoxide dismutase, an antioxidant enzyme coded on chromosome 21. Increased oxidative stress may lead to oxidative damage of important macromolecules. We monitored this damage by measuring levels of different biomarkers of oxidative stress (protein carbonyls and 4-hydroxy-2-nonenal), as well as plasma antioxidant capacity, in children with Down syndrome.

Rapid maxillary expansion and nasal patency in children with Down syndrome.

Down syndrome (DS) is the most common aneuploid disorder at birth. The life expectancy of persons with DS has improved over the last forty years and is now at about sixty years. Phenotypic characteristics include general hypotonia, maxillary hypoplasia with a small oral cavity and a somewhat larger appearing tongue, frequent constricted maxillary arch, nasal obstruction and others.

Uric acid and allantoin levels in Down syndrome: antioxidant and oxidative stress mechanisms?

Background: Down syndrome (DS) is a chromosomal abnormality (trisomy 21) leading to mental retardation, to the characteristic change of individual's phenotype and to the pathological features of Alzheimer disease. Patients with DS have elevated ratio of superoxide dismutase to (catalase plus glutathione peroxidase) with respect to controls in all age categories suggesting that oxidative imbalance contributes to the clinical manifestation of accelerated aging.

Results: We report that persons with DS have elevated uric acid levels compared with controls, 348.

Effect of expanded newborn screening for biochemical genetic disorders on child outcomes and parental stress.

Context: Tandem mass spectrometry now allows newborn screening for more than 20 biochemical genetic disorders. Questions about the effectiveness and risks of expanded newborn screening for biochemical genetic disorders need to be answered prior to its widespread acceptance as a state-mandated program.

Objectives: To compare newborn identification by expanded screening with clinical identification of biochemical genetic disorders and to assess the impact on families of a false-positive screening result compared with a normal result in the expanded newborn screening program.