An international consortium of scientists report mapping another chromosome, this one chromosome 14 -- which is linked to a range of disorders including early-onset Alzheimer's that can strike people in their 30s.

French scientist Roland Heilig, part of the international consortium that did the research, said chromosome 14 had been mapped to the "gold standard." In the past three years, chromosomes 22, 21, and 20 have also been decoded to "gold standard" level, with no gaps left in the genetic sequence.

Chromosome 14 comprises 87,410,661 base pairs, which are the "rungs" that make up about 1,050 genes and gene fragments, according to the research published in the science journal Nature.

Diseases that can be potentially caused by genes in chromosome 14 include early onset Alzheimer's, a severe form of Usher syndrome, which can affect hearing and vision, and the deadly Niemann-Pick disease.

Around 200,000 Americans have early onset Alzheimer's disease, accounting for five percent of the four million American's with Alzheimer's.

"The identification of disease genes will help us find out how diseases develop at a molecular level," Heilig said.

Other sources: Nature