title: Down syndrome in the family: what to do when the karyotype of the proband is not available.
abstract: There is as yet no clear protocol available for counselling a person who has one or more relatives with Down syndrome of unknown genotype. Counsellors use different approaches based on their own experience. We present a protocol for practical use which can be helpful in making a decision in clinical situations such as those mentioned above. In this protocol we have used a simple formula to calculate an approximate risk for the counsellee of having a child with Down syndrome due to an as yet unrecognized familial translocation.
authors.affiliation: Department of Human Genetics, University Hospital Nijmegen, The Netherlands.
authors.forename: J H
authors.initials: JH
authors.lastname: Tuerlings
authors.forename: J C
authors.initials: JC
authors.lastname: Oosterwijk
authors.forename: L P
authors.initials: LP
authors.lastname: ten Kate
mesh_terms: D000328:Adult; D004314:Down Syndrome / Q000235:genetics*; D005260:Female; D005817:Genetic Counseling; D005838:Genotype; D006801:Humans; D007621:Karyotyping; D008297:Male; D010375:Pedigree; D012306:Risk