Legius syndrome

Autosomal dominant - en

Legius syndrome is a rare genetic disorder that is characterized by multiple café-au-lait spots on the skin, freckling in the armpits and groin, and other features that can resemble neurofibromatosis type I (NF1). It is caused by mutations in the SPRED1 gene.

Signs and Symptoms

Individuals with Legius syndrome typically present with:

• Multiple café-au-lait spots
• Freckling in the armpits and groin
• Macrocephaly (large head size)
• Learning disabilities
• Developmental delays

Unlike neurofibromatosis type I, Legius syndrome does not involve the development of neurofibromas, Lisch nodules (iris hamartomas), or optic gliomas.

Genetics

Legius syndrome is caused by mutations in the SPRED1 gene, which is located on chromosome 15q14. The SPRED1 gene encodes a protein that is involved in the Ras/MAPK signaling pathway, which is important for cell growth and differentiation. Mutations in this gene lead to the clinical features observed in Legius syndrome.

Diagnosis

The diagnosis of Legius syndrome is primarily clinical, based on the presence of characteristic skin findings and the absence of other features of neurofibromatosis type I. Genetic testing can confirm the diagnosis by identifying mutations in the SPRED1 gene.

Management

There is no cure for Legius syndrome, and management is primarily supportive. This may include:

• Regular monitoring of skin lesions
• Educational support for learning disabilities
• Developmental assessments and interventions

Differential Diagnosis

Legius syndrome should be differentiated from other conditions that present with similar features, such as:

• Neurofibromatosis type I
• Noonan syndrome
• LEOPARD syndrome

See Also

• Neurofibromatosis type I
• SPRED1
• Ras/MAPK signaling pathway
• Café-au-lait spot