SNP Shot: Genomic Insights

Familial candidiasis is a genetic predisposition to repeated infections caused by Candida, a type of fungus. Those affected often experience persistent and recurring infections of the skin, nails, and mucous membranes (linings of body cavities). This ongoing pattern of infection is referred to as chronic mucocutaneous candidiasis.

Candida is commonly found on the skin and mucous membranes and typically doesn't cause problems. However, certain medications (like antibiotics and corticosteroids) and other factors can sometimes lead to an overgrowth of Candida, resulting in candidiasis. This can occur in the mouth (thrush) or vagina. These common "yeast infections" are usually short-lived and resolved by a healthy immune system.

Most individuals with familial candidiasis develop chronic or recurring yeast infections early in childhood. Skin infections may cause a rash with crusty, thickened areas. When these areas occur on the scalp, they can result in hair loss (scarring alopecia). Nail candidiasis can lead to thickened, cracked, and discolored nails, accompanied by swelling and redness of the surrounding skin. Thrush and gastrointestinal issues such as bloating, constipation, or diarrhea are frequently observed. Women with familial candidiasis are prone to frequent vaginal yeast infections, and infants can develop persistent diaper rash due to skin yeast infections.

Depending on the specific genetic mutation responsible, some individuals with familial candidiasis are at risk for systemic candidiasis. This is a more serious condition where the infection spreads through the bloodstream to organs like the brain and the meninges (membranes surrounding the brain and spinal cord). Systemic candidiasis can be life-threatening.

Chronic or recurrent yeast infections can also occur in individuals without familial candidiasis. Some people experience recurrent candidiasis due to a weakened immune system, resulting from conditions like AIDS or SCID, medications, or other factors. Others may have syndromes, such as APECED or AD-HIES, which include a susceptibility to candidiasis along with other symptoms affecting various body systems.

Inheritance:

Familial candidiasis can be inherited through different patterns. Individuals inherit a tendency to develop recurrent or chronic Candida infections, not the infections themselves. Familial candidiasis caused by mutations in genes like STAT1 follows an autosomal dominant inheritance pattern, meaning only one copy of the mutated gene is sufficient to cause the disorder. Familial candidiasis resulting from mutations in genes like CARD9 or IL17RC follows an autosomal recessive inheritance pattern, requiring both copies of the gene to be mutated. Parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but typically do not exhibit signs or symptoms of the condition.