- Chromosomal anomalies (aberrations).

Chromosomal Aberrations

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

They are a common cause of early spontaneous miscarriage.

Incidence: is about 1 in 150; often cause multiple congenital anomalies and cognitive difficulties.

Acquired chromosomal changes play a significant role in carcinogenesis and tumour progression.

Ü  Risk factors:

1.     Old maternal age > 35 year.

2.     Viral Infection: May affect chromosomes

3.     Radiation: It damages the chromosomes, causing deletions, and translocations.

4.     Drugs during first trimester

5.     Certain genes (e.g gene for fragile-x syndrome XLR predispose to X- chromosome breakage).

6.     Certain chromosome aberration predispose to another aberration e.g parents with balanced translocation carrier predispose to translocation down syndrome of offsprings.

7.     Autoimmune disease: have some role on chromosomal anomalies

Chromosomal aberration could be either:   1- Numerical (click here).      2- Structural.