Nijmegen breakage syndrome (NBS), also known as Berlin breakage syndrome, is a rare genetic disorder that is characterized by a small head, stunted growth, immunodeficiency (weakened immune system), increased sensitivity to radiation therapy, and an increased risk of developing cancer, especially lymphoma.
NBS patients are born with a mutated gene that normally codes for a protein called nibrin. Nibrin helps repair DNA that has been damaged by chromosome breaks. DNA is present inside chromosomes. Therefore, NBS patients are susceptible to chromosomal breakage, which leads to rearrangements of translocations. In other words, one piece of a chromosome is broken off and joined to another chromosome.
Chromosomal rearrangements typically occur in chromosomes 7 and 14, both of which are involved in the development of the immune system.
Since NBS patients are immunocompromised, they have an increased risk of developing infections (especially respiratory tract and urinary tract infections) and cancer. They also have an increased risk of developing learning disabilities and mental retardation. In addition, NBS patients are more susceptible to chromosome breaks when they are exposed to radiation (often used to treat cancer) because they lack the nibrin necessary to repair damaged chromosomes.
The syndrome is named after the city Nijmegen in the Netherlands, where the first case of NBS was described in 1998. Currently, a registry of NBS patients is located in Nijmegen. The registry was developed to study the clinical, laboratory, and genetic features of NBS.
The disorder is extremely rare. About 70 cases have been reported worldwide. A total of 55 patients from 44 families have been enrolled in the Nijmegen registry since 2001. Most NBS patients are of Slavic or other European decent. However, a few cases have also been reported in New Zealand, Mexico, and the United States. Men and women are affected equally.
Patients with NBS have a decreased life span because they have an increased risk of developing infections and cancer. Cancer, especially lymphoma or leukemia, is the most common cause of death in NBS patients, accounting for about one-third of all NBS fatalities. Most NBS patients do not live beyond young adulthood.
Autosomal recessive, BBS, Berlin breakage syndrome, birth defects, cancer, chromosome instability, chromosomes, congenital immunodeficiency, congenital microcephaly, DNA, genetic disease, gastrointestinal infection, genetic disorder, infection, inherited, microcephaly, NBS1, nibrin, respiratory tract infection, Seemanova syndrome, translocations, urinary tract infection.
Nijmegen breakage syndrome (NBS) carriers, individuals diagnosed with NBS or individuals who suspect they may have NBS may benefit from genetic counseling. Genetic counselors work with a patient's healthcare team to provide information to patients about their disorders. They also help patients and their families understand the risks of inheriting a condition, their treatment options, and the risks of passing a disorder on to their children.
Healthcare providers can help patients locate genetic counselors that fit their individual needs.