Nijmegen Breakage Syndrome (NBS) Italian website

Genetic Counselling

This website deals with clinical management, diagnosis, therapeutic options of the disease and genetic counselling in general terms. The information in this website can by no means substitute for medical advice to the individual patient or family.


NBS is a genetic disease with autosomal recessive inheritance caused by biallelic mutations of the NBS1 gene on chromosome 8q21.

The parents of an affected child are obligate heterozygotes (carriers of one mutated allele), while the unaffected sibs have a 2/3 chance to be heterozygous.

A couple in which both partners are heterozygous for a disease-causing mutation in the NBS1 gene has a 25% risk of giving birth to an affected child in each pregnancy, regardless of the sex of the baby.

Click on the picture below to see a schematic representation of NBS inheritance.


The identification of the NBS1 mutation/s causing the disease within the family allows prenatal testing by means of foetal DNA analysis.


Page last updated on: 20th April 2003