Down’s Syndrome and Alzheimer’s Disease: Are Common Genes From Human Chromosome 21 Involved In Both Disorders? In: Fisher A, Hanin I, Lachman C, editors. Alzheimer’s and Parkinson’s Disease. Boston: Springer US; 1986. pp. 271-83. [DOI: 10.1007/978-1-4613-2179-8_34]

Premature thymic involution, observed at the ultrastructural level, in two lineages of human-SOD-1 transgenic mice

The human Cu/Zn superoxide dismutase (hSOD-1) gene, catalyses the dismutation of O2 to H2O2 and O2. It is located on chromosome 21 in q22.1 and is overexpressed in Down's syndrome (DS) patients. These patients present various abnormalities including mental retardation, congenital heart disease, immunological deficits and premature aging. In order to explore the potential role of SOD-1 overexpression in DS, we have generated two lineages of transgenic mice for the hSOD-1 gene and studied, at the ultrastructural level, the effect of hSOD-1 overexpression on the thymic microenvironment. Modification of the cellular architecture and morphology associated with a lipidic invasion, signs of a premature involution of the thymus, were observed in both lineages. A rupture of the filamentous network in the extracellular and probably also in the intracellular matrix was first observed. These results correlate the thymic alterations visualized in light microscopy, on the thymus from DS patients, and raise the question of the relationship between the SOD-1 overexpression and the different morphological alterations associated with the premature thymic involution observed in SOD-1 transgenic mice. They suggest that thymic and immunological impairments present in DS patients may be related to the SOD-1 gene dosage effect.

Down's syndrome: morphological remodelling and increased complexity in the neuromuscular junction of transgenic CuZn-superoxide dismutase mice

Transgenic mice carrying the human CuZn-superoxide dismutase gene were used to investigate whether CuZn-superoxide dismutase gene dosage is involved in the signs of neuromuscular junction deterioration associated with Down's syndrome. Three parameters of neuromuscular junction morphology were studied in hindlimb muscles of CuZn-superoxide dismutase-transgenic mice and their non-transgenic littermates: nerve terminal length, number of nerve terminal branching points and incidence of sprouting that results in synapse formation. These parameters increased with advanced age and the increase occurred earlier in CuZn-superoxide dismutase-transgenic mice. Therefore, the data is in line with the possibility that CuZn-superoxide dismutase-transgenic mice are undergoing premature ageing with respect to neuromuscular junction morphology, most probably owing to a gene dosage effect of CuZn-superoxide dismutase.