Segmental neurofibromatosis in childhood

Area of Science:

• Genetics
• Pediatrics
• Dermatology

Background:

• Segmental neurofibromatosis (NF-1) is a rare variant of NF-1 characterized by localized manifestations.
• It arises from somatic mosaicism due to a post-conceptional mutation in the NF-1 gene.
• While considered rare, its prevalence in specialized centers suggests underdiagnosis in the general population.

Purpose of the Study:

• To report the clinical characteristics and manifestations of segmental neurofibromatosis in a cohort of pediatric patients.
• To highlight the spectrum of symptoms beyond pigmentary changes.
• To emphasize the importance of accurate diagnosis for management and genetic counseling.

Main Methods:

• Retrospective review of 39 children diagnosed with segmental NF-1 at a pediatric NF-1 referral center.
• Analysis of clinical data including age at diagnosis, specific manifestations, and affected body areas.
• Categorization of patients based on the type and extent of NF-1 symptoms.

Main Results:

• The study identified 39 children with segmental NF-1, with a mean age at diagnosis of 7.8 years.
• Most patients (29/39) presented with pigmentary changes (café-au-lait macules and/or freckling).
• A significant minority had isolated plexiform neurofibromas, tibial pseudarthrosis, or optic pathway tumors, underscoring a broader clinical spectrum.

Conclusions:

• Segmental neurofibromatosis, while often presenting with localized pigmentary changes, can manifest as isolated plexiform neurofibromas, pseudarthroses, or optic pathway tumors.
• Accurate diagnosis of segmental NF-1 is critical for appropriate patient management and genetic counseling.
• The findings suggest segmental NF-1 is more common in specialized pediatric settings than previously thought.