Heterozygous means the individual carries 1 copy of a mutation on 1 chromosome. If the mutation is associated with a recessive disease such as FMF, these individuals are called carriers. The carriers are typically unaffected, that is, they show no symptoms of the disease. However, the diagnosis is made clinically, based on1 :
- Recurrent febrile episodes accompanied by peritonitis, synovitis or pleuritis
- Recurrent erysipelas-like erythema
- Repeated laparoscopies for acute abdomen, with no pathology found
- Amyloidosis of the AA type that characteristically develops after age 15 years in untreated individuals, even those who do not have a history of recurrent inflammatory attacks
- Favorable response to colchicine
- Consideration and exclusion of other autoinflammatory diseases
If your patient has a clinical diagnosis of FMF, he/she may carry a second MEFV gene mutation not tested for in our panel. Additional mutation testing may be available for your patient at another lab. Call 866-GENE-INFO to discuss this case with a genetic counselor.
Homozygous means the individual carries 2 copies of the same mutation, 1 on each chromosome. If the mutation is associated with a recessive disease such as FMF, these individuals are typically affected, that is, they show symptoms of the disease. However, the diagnosis is made clinically, based on findings listed above. A homozygous result supports a clinical diagnosis of FMF.
Compound heterozygous means the individual carries 1 copy each of 2 different mutations, 1 on each chromosome. If the mutations are associated with a recessive disease such as FMF, these individuals are typically affected. However, the diagnosis is made clinically, based on findings listed above. A compound heterozygous result supports a clinical diagnosis of FMF.