Aj. Barnicoat et al., DOWN-SYNDROME WITH PARTIAL DUPLICATION AND DEL(21) SYNDROME - STUDY PROTOCOL AND CALL FOR COLLABORATION - STUDY-I - CLINICAL-ASSESSMENT, Clinical genetics, 49(1), 1996, pp. 20-27
We report on the clinical and cyto,aenetic assessment of five cases of
Down syndrome phenotype with either a partial duplication of chromoso
me 21 or a normal karyotype, and we quote a case of del (21q) syndrome
. Down syndromes with a partial duplication of chromosome 21 (as well
as cases of del (21q), which are partly the phenotypic countertype of
trisomy 21) are of paramount importance in the understanding of genes
involved in the phenotype of Down syndrome. The goal is to find the re
levant genes implicated in the main traits of Down syndrome (i.e. ment
al retardation, Alzheimer disease, and serious visceral malformations)
. Such a goal, in our opinion, cannot be reached just by publishing th
e genotype and the phenotype of a small cohort of patients: 1. a suffi
cient number of accurate cases is needed, and 2. data have to be compu
terized for definite conclusions to be reached. The main aims of this
report are to present our study protocol and to invite colleagues to p
articipate in a collaborative study in order to collect a maximum of t
hese (rare) cases.