To evaluate the predictive utility of the number and morphologic appearance of isolated café au lait macules (CALMs) in establishing the diagnosis of neurofibromatosis type 1 (NF1) in a cohort of children referred to an NF1 subspecialty clinic.

Identifying modifiers of glioma risk in patients with type 1 neurofibromatosis (NF1) could help support personalized tumor surveillance, advance understanding of gliomagenesis and potentially identify novel therapeutic targets. Here we report genetic polymorphisms in the human adenylate cyclase gene ADCY8 which correlate with glioma risk in NF1 in a sex-specific manner, elevating risk in females while reducing risk in males. This finding extends earlier evidence of a role for cAMP in gliomagenesis based on results in a genetically engineered mouse model (Nf1 GEM). Thus, sexually dimorphic cAMP signaling might render males and females differentially sensitive to variation in cAMP levels. Using male and female Nf1 GEM, we found significant sex differences exist in cAMP regulation and in the growth promoting effects of cAMP suppression. Overall, our results establish a sex-specific role for cAMP regulation in human gliomagenesis, specifically identifying ADCY8 as a modifier of glioma risk in NF1.

Neurofibromatosis type 1 (NF1) is an inherited autosomal dominant disorder characterized by numerous cutaneous features, including café-au-lait macules, skinfold freckling and iris hamartomas. In addition, individuals with NF1 are prone to the development of both benign and malignant tumors. The most common CNS tumor in children and adults with NF1 is the glioma. In childhood, gliomas are primarily located in the optic pathway, and less frequently in the hypothalamus and brainstem. Regular ophthalmologic evaluations in children are essential for the effective management of these tumors in patients with NF1. Adults, in contrast, are more likely to develop higher grade gliomas, which are treated in a similar fashion as their sporadic counterparts.

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There are currently no objective criteria to evaluate pediatric hypotonia. The purpose of this pilot study was to identify diagnostic criteria for assessing hypotonia in children with Neurofibromatosis type 1 (NF1). Fifty-five subjects between the ages of 1 and 7 years with a diagnosis of NF1 were evaluated. A physical therapist recorded a subjective tone assessment and objective tone metrics, including ankle dorsiflexion, knee extension, hip abduction, triceps fat percentage, grip strength and head lag during a pull-to-sit test. Multivariate logistic regression analysis showed the presence of head lag paired with increased hip range of motion was a significant predictor of hypotonia. The presence of head lag on a pull-to-sit test paired with increased hip range of motion is an accurate predictor of hypotonia in children with NF1. These objective measures should be prospectively evaluated in other pediatric populations for their ability to predict hypotonia.