title: Six cases of partial duplication-deficiency 21 syndrome: 21(dupq22delp23) due to maternal pericentric inversion: inv(21)(p12;q22). A family study.
abstract: Six probands, apparently not related, with a minimal phenotype of Down's syndrome were investigated between 1970 and 1984 in our laboratory. We found in all of them an identical chromosomal abnormality 46,XX or XY,-21,+ der21(dupq22delp23). The der 21 was due to aneusomie de recombinaison, each mother having an abnormal chromosome 21: inv(21)(p12;q22). The fathers' caryotypes were normal. All parents were young and healthy. Pedigrees were established in order to find a relationship between these families. Four of our probands could be related. Familial investigations are still in progress for the last two cases; the ancestors being born in the same small geographical area (within 50 km2) we think that we shall be able to establish a relationship with the others families.
mesh_terms: D002675:Child, Preschool; D002869:Chromosome Aberrations / Q000235:genetics*; D002871:Chromosome Banding; D025063:Chromosome Disorders; D007446:Chromosome Inversion; D002891:Chromosomes, Human, Pair 21; D004314:Down Syndrome / Q000235:genetics; D006580:Genetic Carrier Screening; D006801:Humans; D010375:Pedigree; D010641:Phenotype