Risky Decision Making in Neurofibromatosis Type 1: An Exploratory Study

Can the Cognitive Phenotype in Neurofibromatosis Type 1 (NF1) Be Explained by Neuroimaging? A Review

Neurofibromatosis type 1 (NF1) is one of the most frequent monogenetic disorders. It can be associated with cognitive dysfunctions in several domains such as executive functioning, language, visual perception, motor skills, social skills, memory and/or attention. Neuroimaging is becoming more and more important for a clearer understanding of the neural basis of these deficits. In recent years, several studies have used different imaging techniques to examine structural, morphological and functional alterations in NF1 disease. They have shown that NF1 patients have specific brain characteristics such as Unidentified Bright Objects (UBOs), macrocephaly, a higher volume of subcortical structures, microstructure integrity alterations, or connectivity alterations. In this review, which focuses on the studies published after the last 2 reviews of this topic (in 2010 and 2011), we report on recent structural, morphological and functional neuroimaging studies in NF1 subjects, with special focus on those that examine the neural basis of the NF1 cognitive phenotype. Although UBOs are one of the most obvious and visible elements in brain imaging, correlation studies have failed to establish a robust and reproducible link between major cognitive deficits in NF1 and their presence, number or localization. In the same vein, the results among structural studies are not consistent. Functional magnetic resonance imaging (fMRI) studies appear to be more sensitive, especially for understanding the executive function deficit that seems to be associated with a dysfunction in the right inferior frontal areas and the middle frontal areas. Similarly, fMRI studies have found that visuospatial deficits could be associated with a dysfunction in the visual cortex and especially in the magnocellular pathway involved in the processing of low spatial frequency and high temporal frequency. Connectivity studies have shown a reduction in anterior-posterior “long-range” connectivity and a deficit in deactivation in default mode network (DMN) during cognitive tasks. In conclusion, despite the contribution of new imaging techniques and despite relative advancement, the cognitive phenotype of NF1 patients is not totally understood.

Neurofibromatosis Type 1 with Massive Ventricular Polyposis: First Report in the Medical Literature

BACKGROUND

Neurofibromatosis type 1 (NF1) is a multisystemic disorder with genetic background, characterised by specific cutaneous findings, skeletal dysplasias, and growth of both benign and malignant nervous system tumours. NF1 is caused by mutations in the NF1 gene, situated in chromosome 17q11.2, with an autosomal dominant pattern of inheritance and clinical manifestation of neurofibromas, malignant peripheral nerve sheath tumour, optic and non-optic nerve gliomas, congenital heart disease, cardiovascular and cerebrovascular disease and orthopaedic disorders. The incidence of gastrointestinal manifestations of NF1 is relatively low, compared to neurological disorders, presenting approximately in 5 to 25% of the patient, but later in life.

CASE REPORT

We present a patient with NF1, ventricular polyposis and attentional disorders with cognitive phenotype, while both of her daughters also present with cutaneous manifestations of NF1.

CONCLUSION

To the best of our knowledge, this is the first reported case of NF1 with ventricular polyposis as a gastrointestinal manifestation in the mother and NF1 with no signs of inner organ involvement in both of her daughters.