T-cell immunodeficiency, congenital alopecia, and nail dystrophy

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Reviewed August 2014

What is T-cell immunodeficiency, congenital alopecia, and nail dystrophy?

T-cell immunodeficiency, congenital alopecia, and nail dystrophy is a type of severe combined immunodeficiency (SCID), which is a group of disorders characterized by an almost total lack of immune protection from foreign invaders such as bacteria and viruses. People with this form of SCID are missing functional immune cells called T cells, which normally recognize and attack foreign invaders to prevent infection. Without functional T cells, affected individuals develop repeated and persistent infections starting early in life. The infections result in slow growth and can be life-threatening; without effective treatment, most affected individuals live only into infancy or early childhood.

T-cell immunodeficiency, congenital alopecia, and nail dystrophy also affects growth of the hair and nails. Congenital alopecia refers to an absence of hair that is apparent from birth. Affected individuals have no scalp hair, eyebrows, or eyelashes. Nail dystrophy is a general term that describes malformed fingernails and toenails; in this condition, the nails are often ridged, pitted, or abnormally curved.

Researchers have described abnormalities of the brain and spinal cord (central nervous system) in at least two cases of this condition. However, it is not yet known whether central nervous system abnormalities are a common feature of T-cell immunodeficiency, congenital alopecia, and nail dystrophy.

How common is T-cell immunodeficiency, congenital alopecia, and nail dystrophy?

T-cell immunodeficiency, congenital alopecia, and nail dystrophy is a rare disorder. It has been diagnosed in only a few individuals, almost all of whom are members of a large extended family from a community in southern Italy.

What genes are related to T-cell immunodeficiency, congenital alopecia, and nail dystrophy?

T-cell immunodeficiency, congenital alopecia, and nail dystrophy results from mutations in the FOXN1gene. This gene provides instructions for making a protein that is important for development of the skin, hair, nails, and immune system. Studies suggest that this protein helps guide the formation of hair follicles and the growth of fingernails and toenails. The FOXN1 protein also plays a critical role in the formation of the thymus, which is a gland located behind the breastbone where T cells mature and become functional. Researchers suspect that the FOXN1 protein is also involved in the development of the central nervous system, although its role is unclear.

Mutations in the FOXN1 gene prevent cells from making any functional FOXN1 protein. Without this protein, hair and nails cannot grow normally. A lack of FOXN1 protein also prevents the formation of the thymus. When this gland is not present, the immune system cannot produce mature, functional T cells to fight infections. As a result, people with T-cell immunodeficiency, congenital alopecia, and nail dystrophy develop recurrent serious infections starting early in life.

How do people inherit T-cell immunodeficiency, congenital alopecia, and nail dystrophy?

This condition 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. However, some people who carry one copy of a mutated FOXN1 gene have abnormal fingernails or toenails.

Where can I find information about diagnosis or management of T-cell immunodeficiency, congenital alopecia, and nail dystrophy?

These resources address the diagnosis or management of T-cell immunodeficiency, congenital alopecia, and nail dystrophy, and may include treatment providers.

You might also find information on the diagnosis or management of T-cell immunodeficiency, congenital alopecia, and nail dystrophy, in Educational resources and Patient support.

General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.

To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.

Where can I find additional information about T-cell immunodeficiency, congenital alopecia, and nail dystrophy?

You may find the following resources about T-cell immunodeficiency, congenital alopecia, and nail dystrophy, helpful. These materials are written for the general public.

MedlinePlus - Health information (6 links)
Additional NIH Resources - National Institutes of Health (2 links)
Educational resources - Information pages (6 links)
Patient support - For patients and families (5 links)

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

Genetic Testing Registry - Repository of genetic test information (1 link)
PubMed - Recent literature
OMIM - Genetic disorder catalog

What other names do people use for T-cell immunodeficiency, congenital alopecia, and nail dystrophy?

alymphoid cystic thymic dysgenesis
congenital alopecia and nail dystrophy associated with severe functional T-cell immunodeficiency
Pignata Guarino syndrome
winged helix deficiency

For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines and How are genetic conditions and genes named? in the Handbook.

What if I still have specific questions about T-cell immunodeficiency, congenital alopecia, and nail dystrophy?

Ask the Genetic and Rare Diseases Information Center

Where can I find general information about genetic conditions?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding T-cell immunodeficiency, congenital alopecia, and nail dystrophy?

alopecia ; autosomal ; autosomal recessive ; bacteria ; cell ; central nervous system ; congenital ;deficiency ; dysgenesis ; gene ; immune system ; immunodeficiency ; infection ; inherited ; nervous system ;phenotype ; protein ; recessive ; syndrome ; thymus

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

References (8 links)

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.