Asymptomatic dural ectasia in neurofibromatosis-1: A case report

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Segmental Spinal Neurofibromatosis 1: A Novel Phenotype

Segmental neurofibromatosis (SNF) is a rare subtype of neurofibromatosis (NF). The disease is characterized by features circumscribed to one or more body cutaneous and/or subcutaneous segments. This is a classic example of somatic mosaicism which occurs by postzygotic mutation of the NF1 gene late in the course of embryonic development affecting localized neural crest lines in the fetus. Our case series reported three novel patients who had segmental spinal expression of the disease classified as true mosaic/segmental NF1, along with their management plan treated at one of the largest NF1 center.

Non-invasive Brain Stimulation Modulates GABAergic Activity in Neurofibromatosis 1

Neurofibromatosis 1 (NF1) is a single-gene disorder associated with cognitive phenotypes common to neurodevelopmental conditions such as Autism Spectrum Disorder (ASD) & Attention Deficit Hyperactivity Disorder (ADHD). GABAergic dysregulation underlies working memory impairments seen in NF1. This mechanistic experimental study investigates whether application of anodal transcranial direct current stimulation (atDCS) can modulate GABA and working memory in NF1. 31 adolescents with NF1 were recruited to this single-blind sham-controlled cross-over randomized trial. Active or sham tDCS was applied to the left Dorsolateral Prefrontal Cortex (DLPFC) and Magnetic Resonance Spectroscopy was collected before and after intervention in the left DLPFC and occipital cortex. Higher baseline GABA in the left DLPFC was associated with faster response times (RT) on baseline working memory measures. AtDCS was seen to significantly reduced GABA as compared to sham stimulation in the left DLPFC. There was no effect of atDCS on Glutamate/glutamine (Glx) in the left DLPFC or on GABA/Glx in the occipital cortex. This first such study in adolescents with NF1, showed that atDCS modulates inhibitory activity in the DLPFC. Given the strong evidence linking GABA abnormalities to cognitive deficits across neurodevelopmental conditions such as ASD, modulation of GABA using atDCS offers a promising therapeutic approach.ClinicalTrials.gov Identifier: NCT0499142. Registered 05/08/2021; retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04991428

Alterations in brain morphology by MRI in adults with neurofibromatosis 1

Objective Neurofibromatosis 1 (NF1) is a rare autosomal dominant disease that causes the dysregulated growth of Schwann cells. Most reported studies of brain morphology in NF1 patients have included only children, and clinical implications of the observed changes later in life remain unclear. In this study, we used MRI to characterize brain morphology in adults with NF1. Methods Planar (2D) MRI measurements of 29 intracranial structures were compared in 389 adults with NF1 and 112 age- and sex-matched unaffected control subjects. The 2D measurements were correlated with volumetric (3D) brain measurements in 99 of the adults with NF1 to help interpret the 2D findings. A subset (n = 70) of these NF1 patients also received psychometric testing for attention deficits and IQ and was assessed for clinical severity of NF1 features and neurological problems. Correlation analysis was performed between the MRI measurements and clinical and psychometric features of these patients. Results Four of nine corpus callosum measurements were significantly greater in adults with NF1 than in sex- and age-matched controls. All seven brainstem measurements were significantly greater in adults with NF1 than in controls. Increased corpus callosum and brainstem 2D morphology were correlated with increased total white matter volume among the NF1 patients. No robust correlations were observed between the 2D size of these structures and clinical or neuropsychometric assessments. Conclusion Our findings are consistent with the hypothesis that dysregulation of brain myelin production is an important manifestation of NF1 in adults.

Neuroanatomical correlates of working memory performance in Neurofibromatosis 1

Background: Neurofibromatosis 1 (NF1) is a single-gene neurodevelopmental disorder associated with cognitive and behavioural impairments, particularly with deficits in working memory. This study investigates the cerebral volumetric differences in adolescents with NF1 as compared to typically developing controls and how working memory task performance is associated with these differences. Methods: 31 adolescents aged 11-17 years were compared to age and sex-matched controls. NF1 subjects were assessed using detailed multimodal measurement of working memory at baseline followed by a 3T MR scan. A voxel-based morphometry approach was used to estimate the total and regional gray matter(GM) volumetric differences between the NF1 and control groups. The working memory metrics were subjected to a principal component analysis (PCA) approach. Finally, we examined how the components derived from PCA correlated with the changes in GM volume in the NF1 group, after adjusting for age, sex and total intracranial volume. Results: The NF1 cohort showed increased GM volumes in the thalamus, globus pallidus, caudate, putamen, dorsal midbrain and cerebellum bilaterally as compared to controls. The PCA yielded three independent behavioural components reflecting high memory load, low memory load and auditory working memory. Correlation analyses revealed that increased volume of the inferior lateral parietal cortex was associated with poorer performance on the high working memory load tasks. Increased volume of posterior cingulate cortex, a key component of the default mode network (DMN) was significantly associated with poorer performance on low working memory load tasks. Discussion: This is the first study to examine the neuroanatomical correlates of working memory in NF1 adolescents. Consistent with prior literature we show larger subcortical brain volumes in in the NF1 cohort. The strong association between posterior cingulate cortex volume and performance on low memory load conditions supports previously suggested hypotheses of deficient DMN structural development, which in turn may contribute to the cognitive impairments in NF1.

Endocrine Conditions in Neurofibromatosis 1

Neurofibromatosis 1 (NF1) is an autosomal-dominant multisystemic neurocutaneous disorder primarily affecting the skin, bone and the nervous system. It has been long appreciated that NF1 is often associated with endocrine disorders. In this chapter, we will discuss the endocrine disorders associated with NF1. The most common endocrinological disorders in NF1 are short stature with or without growth hormone deficiency, central precocious puberty, growth hormone excess. Less common endocrine-related conditions in NF1 include gynecomastia, diencephalic syndrome and the presence of endocrine tumors like pheochromocytoma.