Legius syndrome | |
---|---|
Other names | Neurofibromatosis 1-like syndrome [1] |
This condition is inherited in an autosomal dominant manner. | |
Symptoms | café au lait spots; +/- learning disabilities [2] |
Usual onset | at birth |
Causes | Mutations in the SPRED1 gene [3] |
Diagnostic method | Clinical findings, Genetic test [4] |
Differential diagnosis | neurofibromatosis type I |
Treatment | Physical therapy, Speech therapy [2] [1] |
Prognosis | good |
Frequency | rare (estimated at 1:46,000-1:75,000) [2] |
Legius syndrome (LS) is an autosomal dominant condition characterized by cafe au lait spots. [3] It was first described in 2007 and is often mistaken for neurofibromatosis type I. It is caused by mutations in the SPRED1 gene. [5] [6] It is also known as neurofibromatosis type 1-like syndrome. [1]
Nearly all individuals with Legius syndrome show multiple café au lait spots on their skin. [7] Symptoms may include: [2]
Features common in neurofibromatosis – like Lisch nodules (iris hamartomas diagnosed on slit lamp exam), bone abnormalities, neurofibromas, optic pathway gliomas and malignant peripheral nerve sheath tumors – are absent in Legius syndrome. [1]
Legius syndrome is a phakomatosis [8] and a RASopathy, a developmental syndrome due to germline mutations in genes. [7] [9] The condition is autosomal dominant in regards to inheritance and caused by mutations to the SPRED1 gene at chromosome 15, specifically 15q14 (or (GRCh38): 15:38,252,086-38,357,248). [10] [11] The gene in question demonstrates almost 100 mutations. [1]
A mutated SPRED1 protein adversely regulates Ras-MAPK signaling, which is a chain of proteins in a cell that sends signals from the surface of a cell to the nucleus which in turn causes the symptoms of this condition. [2] [12]
Genetic testing is necessary to identify the syndrome. The DNA test is necessary sometimes, because symptoms may not be sufficient to definitely diagnose this condition. [4] [1] [13]
The symptoms of Legius syndrome and neurofibromatosis type I are very similar; An important difference between Legius syndrome and neurofibromatosis type I is the absence of tumor growths Lisch nodules and neurofibromas which are common in neurofibromatosis type I. [2]
A genetic test is often the only way to make sure a person has Legius syndrome and not neurofibromatosis type I; 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.[ medical citation needed]
Management of Legius syndrome is done via the following: [2] [1]
The prognosis of this condition is generally considered good with appropriate treatment.[ citation needed]
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