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.

Down syndrome: otolaryngological effects of rapid maxillary expansion.

Objective: Phenotypical Down syndrome includes pharyngeal and maxillary hypoplasia and, frequently, constricted maxillary arch with nasal obstruction.

Study Design: This clinical trial assessed the effects of rapid maxillary expansion on ENT disorders in 24 children with Down syndrome randomly allocated to receive either rapid maxillary expansion or not. Each group received ENT and speech therapy assessments before expansion and after the device had been removed.

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.

Newborn screening compared to clinical identification of biochemical genetic disorders.

A group of 28 patients with inherited metabolic disease (homocystinuria galactosaemia, maple syrup urine disease and biotinidase deficiency) diagnosed by screening were compared with a group of 17 similar patients identified clinically. The rate of hospitalization was similar for the two groups. The patients diagnosed clinically showed a higher incidence of mental retardation and their parents experienced greater stress and found greater difficulty in meeting their child's needs.

Influence of age on activities of antioxidant enzymes and lipid peroxidation products in erythrocytes and neutrophils of Down syndrome patients.

Thirty-seven individuals with Down syndrome (DS) were divided into four age categories: (i) 1 to < 6 years, (ii) 6 to < 13 years, (iii) 13 to < 20 years, and (iv) over 20 years. Activities of antioxidant enzymes found in individual age categories were different, but the differences between age groups were not statistically significant. We confirmed significantly higher activities of Cu/Zn superoxide dismutase (SOD) and glutathione peroxidase (GPx) in blood cells of people with DS as compared to 35 controls, which consisted, for the first time, of siblings of children with DS.

Novel mutations in the GALK1 gene in patients with galactokinase deficiency.

Galactokinase deficiency is an inborn error of galactose metabolism whose major clinical manifestation is the development of cataracts during the first months of life. Only 20 mutations have been reported to date and understanding of the functionally important domains of the galactokinase protein is still limited. Here we report four novel mutations in GALK1 that were identified in two unrelated patients with galactokinase deficiency.

Towards optimal mental health of persons with Down syndrome.

This paper outlines the risk of mental health disorders in adults with Down syndrome and considers the practical ways in which positive well-being can be promoted. It emphasises that prevention begins at birth and parents need to be alerted to positive child-rearing strategies from infancy.

A prevalence study of celiac disease in persons with Down syndrome residing in the United States of America.

In order to estimate the prevalence of celiac disease in persons with Down syndrome, 105 patients with this chromosomal disorder residing on the East Coast of the United States of America were enrolled in this study. IgA and IgG antigliadin antibodies (AGA) were determined using a fluorescent immunoenzymatic assay, and antiendomysium antibodies (AEA) were measured with immunofluorescence on monkey oesophagus. Of the 105 patients, 5 were positive for AEA, 4 were positive for IgG AGA, and 1 was positive for IgG AGA and AEA.

Amblyopia and visual acuity in children with Down's syndrome.

Background/aims: Amblyopia in people with Down's syndrome has not been well investigated. This study was designed to determine the prevalence and associated conditions of amblyopia in a group of home reared children with Down's syndrome.

Methods: All children in the study group underwent an evaluation of visual acuity.

Atypical background somatic mutant frequencies at the HPRT locus in children and adults with Down syndrome.

People with Down syndrome are 10-30 fold more likely to develop leukemia than the normal population. To date, little is known regarding the molecular mechanisms underlying this phenomenon. We have previously demonstrated that the spontaneous somatic mutant frequency (Mf) at a reporter gene, hypoxanthine-guanine phosphoribosyl transferase (HPRT), from a normal population showed a strict age dependency with an exponential increase in Mf from birth to late adolescents with a subsequent linear 2-5% increase per year in adults.

Should children with Down syndrome be screened for atlantoaxial instability?

In 1995, the Committee on Sports Medicine and Fitness of the American Academy of Pediatrics (AAP) published a position paper on atlantoaxial instability in children with Down syndrome in which a previous statement on the same subject published in 1984 (Table) was retired. The 1995 statement includes several arguments that disfavor screening of children with Down syndrome for atlantoaxial instability. Whereas some of these arguments are well founded, other lack substantive evidence that would support the statement.

Cerebrohepatorenal (Zellweger) syndrome: clinical, neuropathological, and biochemical findings.

An infant with Zellweger syndrome is reported. A detailed description of the clinical findings is provided. In particular, the neuropathological aspects are highlighted and the underlying biochemical derangements discussed.

Guidelines for optimal medical care of persons with Down syndrome. International League of Societies for Persons with Mental Handicap (ILSMH).

There are numerous clinical conditions observed in persons with Down syndrome, as described above, which should be taken into consideration in the course of their medical care and management. If provided with optimal medical services, pursuing specific evaluations and examinations, with a focus on preventive aspects and fostering well being in all areas of human functioning, the quality of life of individuals with Down syndrome can be enhanced significantly and their contribution to society substantial.

Major depression in a small group of adults with Down syndrome.

The clinical histories and treatment of the nine individuals with Down syndrome (DS) and major depression (MD) previously noted in a report on the psychopathology of a population of 164 adults with DS with and without health disorders from a Down Syndrome Clinic are presented (Myers & Pueschel, 1991). The clinical characteristics including DSM-III-R (1987) criteria of these 9 patients plus 13 individuals with DS and MD described in case reports in the literature are summarized. Depression is rarely verbalized and commonly appears as crying, depressed appearance, or mood lability.

Tardive or atypical Tourette's disorder in a population with Down syndrome?

In a population of 425 individuals with Down syndrome, we observed 5 persons (1.2%) with Tourette's disorder. Because the prevalence of Tourette's disorder in the general population has been estimated to be between 0.

Posterior occipitoatlantal hypermobility in Down syndrome: an analysis of 199 patients.

We endeavored to determine the prevalence of occipitoatlantal hypermobility in individuals with Down syndrome, to establish objective radiographic criteria for this entity, and to correlate this with neurologic abnormality. In a retrospective analysis, upper cervical spine radiographs of 210 patients with Down syndrome were compared with those of 102 normal individuals. Radiographs were evaluated using the Powers ratio.

Environmental and temperament assessments of children with Down's syndrome.

This study was designed to investigate the family environment and the temperament of children with Down's syndrome (DS). Parents of 40 children with DS completed the Family Environmental Scale (FES). They also were asked to fill out the Temperament Assessment Battery for Children (TABC) for both the child with DS and the nearest same-sex sibling.

Mitral valve prolapse in persons with Down syndrome.

This study was designed to determine the prevalence of mitral valve prolapse and aortic insufficiency in home-reared, young persons with Down syndrome. Of the 36 individuals (ages 20-32 years) enrolled in this study, 20 had abnormal echocardiographic findings. Thirteen patients had mitral valve prolapse, 3 had both mitral valve prolapse and aortic insufficiency, 2 had only aortic insufficiency, and 2 had other mitral valve disorders.