Legius syndrome
Encyclopedia
Legius syndrome is an autosomal dominant condition characterized by cafe au lait spot
s. It is often mistaken for Neurofibromatosis type I
(NF-1). It is caused by mutations in the SPRED1 gene
. It is also known as Neurofibromatosis Type 1-like syndrome (NFLS).
The syndrome is named after Eric Legius, Professor at the Catholic University of Leuven
. It is a RASopathy
.
The test checks for loss of function mutations in the SPRED1 gene.
The similarity of symptoms stem from the fact that the different genes affected in the two syndromes code for proteins that carry out a similar task in the same reaction pathway.
An important difference is the absence of tumor growths (Lisch nodules
and Neurofibromas which are common in NF-1) in LS.
Because of this difference, Legius syndrome is often seen as the less severe of the two syndromes.
Café au lait spot
Café au lait spots or Café au lait macules are pigmented birthmarks. The name café au lait is French for "milky coffee" and refers to their light-brown color...
s. It is often mistaken for Neurofibromatosis type I
Neurofibromatosis type I
Neurofibromatosis type I , formerly known as von Recklinghausen disease after the researcher who first documented the disorder, is a human genetic disorder. It is possibly the most common inherited disorder caused by a single gene...
(NF-1). It is caused by mutations in the SPRED1 gene
SPRED1 gene
Sprouty-related, EVH1 domain-containing protein 1 is a protein that in humans is encoded by the SPRED1 gene located on chromosome 15q13.2 and has seven coding exons.- Function :...
. It is also known as Neurofibromatosis Type 1-like syndrome (NFLS).
The syndrome is named after Eric Legius, Professor at the Catholic University of Leuven
Katholieke Universiteit Leuven
The Katholieke Universiteit Leuven is a Dutch-speaking university in Flanders, Belgium.It is located at the centre of the historic town of Leuven, and is a prominent part of the city, home to the university since 1425...
. It is a RASopathy
RASopathy
The RASopathies are developmental syndromes caused by germline mutations in genes that alter the Ras subfamily and Mitogen-activated protein kinase that control Signal transduction, including:*Capillary malformation-AV malformation syndrome...
.
Symptoms
Nearly all patients show multiple Café au lait spots. Other symptoms may include:- Freckles in the armpits and/or groin
- LipomasLipomaA lipoma is a benign tumor composed of adipose tissue. It is the most common form of soft tissue tumor. Lipomas are soft to the touch, usually movable, and are generally painless. Many lipomas are small but can enlarge to sizes greater than six centimeters. Lipomas are commonly found in adults...
- MacrocephalyMacrocephalyMacrocephaly , occurs when the head is abnormally large; this includes the scalp, the cranial bone, and the contents of the cranium.-Causes:...
- Learning disabilities
- ADHD
- Developmental delay
Diagnosis
Genetic testing is necessary to identify the syndrome.The test checks for loss of function mutations in the SPRED1 gene.
Confusion with Neurofibromatosis Type I
the symptoms of Legius syndrome and NF-1 are very similar. This is the reason why the two are easily confused. A genetic test is often the only way to make sure a person has LS and not NF-1.The similarity of symptoms stem from the fact that the different genes affected in the two syndromes code for proteins that carry out a similar task in the same reaction pathway.
An important difference is the absence of tumor growths (Lisch nodules
Lisch nodules
A Lisch nodule is a pigmented hamartomatous nodular aggregate of dendritic melanocytes affecting the iris, named after Austrian ophthalmologist Karl Lisch , who first recognized them in 1937....
and Neurofibromas which are common in NF-1) in LS.
Because of this difference, Legius syndrome is often seen as the less severe of the two syndromes.