Juvenile hyaline fibromatosis is a disorder that affects the skin, joints, and bones. Individuals with this condition typically begin to develop signs and symptoms within the first few years of life. Juvenile hyaline fibromatosis is characterized by skin bumps that frequently appear on the hands, neck, scalp, ears, and nose. These skin bumps can also develop in joint creases and the genital region. They vary in size and are sometimes painful. Affected individuals usually develop more skin bumps over time.
Juvenile hyaline fibromatosis is also characterized by overgrowth of the gums (gingival hypertrophy) and joint deformities (contractures) that can impair movement. In addition, affected individuals may grow slowly and have bone abnormalities. People with juvenile hyaline fibromatosis typically have severe physical limitations, but most individuals have normal intelligence and live into adulthood.
The prevalence of juvenile hyaline fibromatosis is unknown. About 70 people with this disorder have been reported.
Mutations in the ANTXR2 gene (also known as the CMG2 gene) cause juvenile hyaline fibromatosis. The ANTXR2 gene provides instructions for making a protein involved in the formation of tiny blood vessels (capillaries). Researchers believe that the ANTXR2 protein is also important for maintaining the structure of basement membranes, which are thin, sheet-like structures that separate and support cells in many tissues.
The signs and symptoms of juvenile hyaline fibromatosis are caused by the accumulation of a clear (hyaline) substance in different parts of the body. The nature of this substance is not well known, but it is likely made up of protein and sugar molecules. Researchers suspect that mutations in the ANTXR2 gene disrupt the formation of basement membranes, allowing the hyaline substance to leak through and build up in various body tissues.
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.
- inherited systemic hyalinosis
- juvenile hyalinosis
- molluscum fibrosum
- Murray syndrome
- Puretic syndrome
- Systemic hyalinosis