Thursday, June 5, 2008

- Chromosomal anomalies (aberrations).

- Defenition:-

is a deviation from the normal number (numerical aberrations)or the normal shape(morphology) of chromosomes(structural aberrations).

- Origin:-
(1)Chromosomal anomalies at germ cell level.

-It originates during the formation of germ cells.
-It present in all body cells.
-It appear in karyotyping.
-It may involve Autosomes or sex chromosomes.

*Anomalies involving Autosomes may be:-:-
*Anomalies involving sex chromosomes may be:-
(2)Chromosomal anomalies at somatic cell level.

-It originates during the formation of somatic cells.
-It present in certain cell population.
-It doesnot appear in karyotyping(i.e normal karyotype),but appear in karyotyping of the affected cells.
-It may involve Autosomes & may be:-
  • Numerical e.g polyploidy,aneuploidy.
  • Structural e.g philadelphia chromosome.

  • Teratogens.
  • Pregnancy in old age.
  • Family history of Chromosomal anomalies.

-Priciples of histology vol1,staff members ,faculty of medicine,mansoura university,ch3,p.g70,71,72,78.

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