Division of Medical Genetics, University of Geneva Medical School and University Hospitals, Geneva, Switzerland. Stylianos.Antonarakis@medecine.unige.ch
Last year we celebrated the sequencing of the entire long arm of human chromosome 21. This achievement now provides unprecedented opportunities to understand the molecular pathophysiology of trisomy 21, elucidate the mechanisms of all monogenic disorders of chromosome 21, and discover genes and functional sequence variations that predispose to common complex disorders. All these steps require the functional analysis of gene products and the determination of the sequence variation of this chromosome.