Down syndrome is caused by a translocation of chromosomes 15 and 21 (Figure 3), in which the long arms of two acrocentric chromosomes are translocated to produce a single long chromosome ...

The genetic cause for the most common type of hearing loss in children with Down syndrome has been identified in mice by researchers at UCL, the Francis Crick Institute and MRC Harwell Institute.

Down syndrome, for example, is caused by a trisomy—three copies instead of two—of chromosome 21. Amniocentesis and chorionic villus sampling ... After the tags were identified, Quake’s group could ...

A Down syndrome test is used to discover whether an unborn baby has Down syndrome, a genetic condition caused by an extra copy of chromosome 21. Down syndrome occurs in about 1 out of every 1,000 ...

Cells from buccal smears were positive for sex chromatin. Only 14 cells obtained from bone marrow could be subjected to chromosome analysis. Of these, 13 had 48, and 1 had 50 chromosomes.

Over the years, scientists have attempted to map the genetic determinants of CHD on chromosome 21 using human samples and ... suggesting that three copies of the gene impair mitochondrial function in ...