ABSTRACT
Nijmegen breakage syndrome (NBS, MIM 251260) is extremely rare. Inheritance follows an autosomal recessive modus with complete penetrance. We are aware of some 70 families worldwide, the majority of which are in central and eastern Europe. The observed carrier frequency in Poland, Ukraine, and the Czech Republic is 1:177; however, considerably fewer than the expected 1:95,000 patients have been currently ascertained (1).
