Chromatin is the container for all of the DNA within the cell nucleus. During mitosis of human cell division chromatin is segregated into 46 duplicated chromosomes, and one member of each duplication is passed to each of the new daughter cells. In addition to the DNA content of each chromosome, protein, RNA, lipid, hormone and vitamin chromatin components are passed to the new cells, which now extend the chromatin to either active, elongated euchromatin microfibrils, 10 nm. (100A.) in caliber, or retain other portions of the chromatin in a condensed, coiled and repressed heterochromatin state.

Diseases of chromatin and chromosomes can be recognized by karyotype analysis of the set of 46 duplicated chromosomes at the time of mitosis, or by the RNA or protein product of euchromatin during cell interphase. This karyotype data and transcription data can be correlated with the clinical features of the individual patient, and provides the basis for the classification and therapy of genetic (DNA sequences) and epigenetic (RNA and protein regulatory sequences) diseases.

In addition to such diseases, this karyotype and transcription data provides the basis for current research into mechanisms of gene regulation in neoplastic diseases and the immune response, organ regeneration and embryogenesis, and understanding the molecular basis of cell differentiation and hormone action.

It is likely that such understanding will permit effective therapy of chromatin and chromosomal diseases in selected patients.

References:

1. Frenster JH, and Herstein PR, "Gene De-Repression", New Eng. J. Med. vol. 288: pp. 1224-1228,
(June 7, 1973).