Legius syndrome is a neurocutaneous disease, one of the RASopathies, and is characterized by multiple café-au-lait spots, with or without freckles and macrocephaly.
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Epidemiology
More than 200 cases were reported between 2007 and 2013 1,3.
Although rare, it is estimated that up to 2% of patients fulfilling diagnostic criteria for neurofibromatosis-1 (without NF1 gene mutations) have Legius syndrome.
Clinical presentation
Besides the characteristic café-au-lait spots, other possible findings are:
- freckles
- macrocephaly.
- pectus excavatum or carinatum
- Noonan-like face
- lipomas
- learning disabilities and behavioral problems (less severe than in NF1)
Pathology
The disease is caused by a heterozygous mutation in the SPRED1 gene, which acts as a negative regulator of RAS pathway and interacts with neurofibromin, the product of the NF1 gene.
Many different allelic variants have been found, however, without genotype-phenotype correlation.
History and etymology
Legius syndrome was named after Eric Legius (fl. 2021) who is credited with first describing it.