The underlying causes of CVID are largely obscure. Genetic mutations can be identified as the cause of disease in about 10% of people, while familial inheritance accounts for 10–25% of cases. Rather than arising from a single genetic mutation, CVID seems to result from variety of mutations that all contribute to a failure in antibody production. Mutations in the genes encoding ICOS, TACI, CD19, CD20, CD21, CD80 and BAFFR have been identified as causative of CVID. Susceptibility to CVID may also be linked to the major histocompatibility complex (MHC) of the genome, particularly to DR-DQ haplotypes. A mutation in the NFKB2 gene has recently been shown to cause CVID-like symptoms in a murine model. The frequency of this NFKB2 mutation in the CVID population is, however, yet to be established. Diagnosis
According to a European registry study, the mean age at onset of symptoms was 26.3 years old. As per the criteria laid out by ESID (European Society for Immunodeficiencies) and PAGID (Pan-American Group for Immunodeficiency), CVID is diagnosed if:
the person presents with a marked decrease of serum IgG levels (<4.5 g/L) and a marked decrease below the lower limit of normal for age in at least one of the isotypes IgM or IgA;
the person is four years of age or older;
the person lacks antibody immune response to protein antigens or immunization.Diagnosis is chiefly by exclusion, i.e. alternative causes of hypogammaglobulinemia, such as X-linked agammaglobulinemia, must be excluded before a diagnosis of CVID can be made.
The outlook for people varies greatly depending on their level of lung and other organ damage prior to diagnosis and treatment. Epidemiology
CVID has an estimated prevalence of about 1:50,000 in Caucasians. The disease seems to be less prevalent amongst Asians and African-Americans. Males and females are equally affected; however, among children, boys predominate. A recent study of people in Europe with primary immunodeficiencies found that 30% had CVID, as opposed to a different immunodeficiency. 10–25% of people inherited the disease, typically through autosomal-dominant inheritance. Given the rarity of the disease, it is not yet possible to generalize on disease prevalence among ethnic and racial groups. CVID shortens the life-span; but no study currently has a median age recorded. One study suggests the median age of death for men and women is 42 and 44 years old, respectively, but most patients involved in the study are still alive. Those people with accompanying disorders had the worst prognosis (50% survival 33 years after diagnosis) and those people with only CVID-caused frequent infections had the longest survival rates, with another study stating a life expectancy almost equalling that of the general UK population. Additionally, people with CVID with one or more noninfectious complications have an 11 times higher risk of death as compared to people with only infections. History
Immunodeficiencies comprise many diseases and are genetic defects affecting the immune system. There are roughly 150 immunodeficiencies spanning over 120 genetic defects.Charles Janeway Sr. is generally credited with the first description of a case of CVID in 1953.