Once dare, today casual, the project of the human genome basic structure analysis celebrated its first major accomplishment when the almost complete sequence of the twenty-second chromosome was published. Though the chromosome represents only hardly more than 1.5 % of the total genomic DNA, it is comparatively rich from the point of gene content (545 hitherto identified gene sequences) and it is important from the medicinal point of view. Among pathologic states resulting from its impaired function inborn heart and major vessel defects, mental disorders, and malignities are rated.

        Key words: human 22nd chromosome, sequence of nucleotides, genes, syndromes.