Familial candidiasis

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Familial candidiasis is an inherited tendency to develop infections caused by a type of fungus called Candida. Affected individuals typically have infections of the skin, the nails, and the moist lining of body cavities (mucous membranes). These infections are recurrent and persistent, which means they come back repeatedly and can last a long time. This pattern of infection is called chronic mucocutaneous candidiasis.

Candida is commonly present on the skin and on the mucous membranes, and in most people usually causes no health problems. However, certain medications (such as antibiotics and corticosteroids) and other factors can lead to occasional overgrowth of Candida (candidiasis) in the mouth (where it is known as thrush) or in the vagina. These episodes, commonly called yeast infections, usually last only a short time before being cleared by a healthy immune system.

Most people with familial candidiasis have chronic or recurrent yeast infections that begin in early childhood. Skin infections lead to a rash with crusty, thickened patches; when these patches occur on the scalp, they can cause loss of hair in the affected area (scarring alopecia). Candidiasis of the nails can result in thick, cracked, and discolored nails and swelling and redness of the surrounding skin. Thrush and gastrointestinal symptoms such as bloating, constipation, or diarrhea are common in affected individuals. Women with familial candidiasis can develop frequent vaginal yeast infections, and infants can have yeast infections on the skin that cause persistent diaper rash.

Depending on the genetic change involved in this condition, some affected individuals are at risk for developing systemic candidiasis, a more severe condition in which the infection spreads through the bloodstream to various organs including the brain and the meninges, which are the membranes covering the brain and spinal cord. Systemic candidiasis can be life-threatening.

Chronic or recurrent yeast infections can occur in people without familial candidiasis. Some individuals experience recurrent candidiasis as part of a general susceptibility to infections because their immune systems are impaired by a disease such as acquired immune deficiency syndrome (AIDS) or severe combined immunodeficiency (SCID), medications, or other factors. Other individuals have syndromes such as autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) or autosomal dominant hyper-IgE syndrome (AD-HIES) that include a tendency to develop candidiasis along with other signs and symptoms affecting various organs and systems of the body.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

Mutations in any of several genes have been identified in people with familial candidiasis. These genes include CARD9, IL17RC, STAT1, and others. The genes associated with familial candidiasis provide instructions for making proteins that are involved in immune system function.

When the immune system recognizes Candida, it generates cells called Th17 cells. These cells produce signaling molecules (cytokines) called the interleukin-17 (IL-17) family as part of an immune process called the IL-17 pathway. The IL-17 pathway creates inflammation, sending other cytokines and white blood cells that fight foreign invaders and promote tissue repair. In addition, the IL-17 pathway promotes the production of certain antimicrobial protein segments (peptides) that control growth of Candida on the surface of mucous membranes.

The gene mutations associated with familial candidiasis interfere with the IL-17 pathway in various ways. Mutations in several genes, including IL17RC, impair signaling in the IL-17 pathway. Mutations in other genes, including STAT1 and CARD9, are thought to block (inhibit) the activity of the pathway. Impairment of the IL-17 pathway diminishes the body's immune response to Candida, leading to the chronic or recurrent yeast infections that occur in people with familial candidiasis. Mutations in most of the genes associated with familial candidiasis cause chronic mucocutaneous candidiasis; only CARD9 gene mutations have also been known to lead to systemic candidiasis in some affected individuals.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

Familial candidiasis can be inherited in different patterns. People with this disorder inherit a tendency to develop recurrent or chronic Candida infections, not the infections themselves. Familial candidiasis caused by mutations in some genes, including STAT1, is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.

Familial candidiasis caused by mutations other genes, such as CARD9 or IL17RC, is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

Candida is present on the skin and mucous membranes of up to half the population at any given time, normally without creating health problems. The prevalence of the inherited susceptibility to Candida infections that characterizes familial candidiasis is unknown, but the condition is thought to be rare.

Which doctor should you see?

The suggested department for discussing Familial candidiasis is Clinical Genetics, with a clinical geneticist as the relevant type of clinician. Paediatrician (children) or physician (adults), with clinical geneticist referral.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Does the exact genetic or chromosome finding explain the observed features?
• Would a genetic counsellor help the family understand the result?
• Which organ-specific assessments are appropriate for this particular diagnosis?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Familial candidiasis. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.