Milroy's disease, also known as hereditary lymphedema, is a genetic disorder caused by congenital defects in the lymphatic system. Congenital defects occur during the development of the fetus. Therefore the symptoms of this disease are present at birth. The website, Lymphedema People, reports Milroy's disease is the rarest form of inherited lymphedema, accounting for only two percent of hereditary lymphedemas. An article in the journal "Prenatal Diagnosis" reports that Milroy's disease is a life-long condition, but does not decrease lifespan.
Lymphatic System
The lymphatic system transports fluid similar to blood plasma from tissues all over the body. The fluid is transported by a network of lymphatic vessels, which transport water, nutrients and the white blood cells that fight infections.
Genetics
In the August 2000 issue of the "American Journal of Human Genetics" researchers identified a gene responsible for causing Milroy's disease. It was vascular endothelial growth factor 3, or VEGFR3, which is a protein specific to lymphatic vessels. The defect in this single gene impairs the formation of lymphatic vessels during fetal development causing the symptoms of Milroy's disease. The disease is inherited in an autosomal dominant manner, meaning that offspring of a parent with the disease have a 50 percent chance of also having Milroy's disease. A review article in "Gene Reviews" does note that the genetic defect in VEGFR3 is present in only 75 percent of cases, so other genes are likely involved.
Edema
The malformations in the lymphatic vessels cause a decrease in the drainage of fluid in tissues, especially in the extremities. The most prominent feature at birth of Milroy's disease is swelling in the feet. It is sometimes accompanied by skin growths on the toes, called papillomas and up-turned toenails. A study in the "Journal of Medical Genetics" reported that fluid accumulated in the groin area of 37 percent of males with Milroy's disease, and a few of these males had problems with urination.
Cellulitis
The obstruction of normal lymph flow can predispose individuals with Milroy's disease to recurrent bacterial infections. A study in the "Journal of Medical Genetics" reported that 14 of 71 patients with Milroy's disease had cellulitis. The symptoms of cellulitis are increased pain and redness in the swollen limb, high fever and chills. Antibiotic treatment resolves this condition. Untreated cellulitis can further damage the lymphatic vessels and increase swelling.
Steatorrhea
Steatorrhea refers to stools with excess fat in them. A case report in a French journal reported the coexistence of steatorrhea in a patient with Milroy's disease . The lymphatic system plays a role in dietary fat distribution and congenital defects in lymphatic vessels may impair the distribution of fats to other tissues. Steatorrhea is not a common symptom of Milroy's disease.
Treatment
A review article published on April 2006 in "Gene Reviews" reports that the swelling and complications of Milroy's disease can be effectively treated with compression stockings or bandaging and massage. The article further notes that bacterial infections can be reduced by good hygiene practices and prompt initiation of antibiotic treatment.
References
- Lymphedema People: Milroy's Disease
- "Prenatal Diagnosis;" Prenatal Diagnosis of Milroy's Primary Congenital Lymphedema; I.R. Makhoul et al.; September 2002
- "American Journal of Human Genetics;" Congenital Hereditary Lymphedema Caused by a Mutation that Inactivates VEGFR3 Tyrosine Kinase; Alexandre Irrthum et al.; August 2000
- "Journal of Medical Genetics;" Milroy disease and the VEGFR-3 mutation phenotype; G. Brice et al.; 2004
- "Gene Reviews;" Milroy Disease; G. Brice et al.; April 2006
