Widespread ischemic brain lesions caused by vasculopathy associated with neurofibromatosis type 1

Familial idiopathic basal ganglia calcification: Histopathologic features of an autopsied patient with an SLC20A2 mutation

Idiopathic basal ganglia calcification (IBGC), or Fahr's disease, is a neurological disorder characterized by widespread calcification in the brain. Recently, several causative genes have been identified, but the histopathologic features of the brain lesions and expression of the gene products remain unclear. Here, we report the clinical and autopsy features of a 62-year-old Japanese man with familial IBGC, in whom an SLC20A2 mutation was identified. The patient developed mild cognitive impairment and parkinsonism. A brain CT scan demonstrated abnormal calcification in the bilateral basal ganglia, thalami and cerebellum. An MRI study at this point revealed glioblastoma, and the patient died 6 months later. At autopsy, symmetric calcification in the basal ganglia, thalami, cerebellar white matter and deeper layers of the cerebral cortex was evident. The calcification was observed in the tunica media of small arteries, arterioles and capillaries, but not in veins. Immunohistochemistry using an antibody against type III sodium-dependent phosphate transporter 2 (PiT-2), the SLC20A2 product, demonstrated that astrocytic processes were labeled in several regions in control brains, whereas in the patient, reactivity in astrocytes was apparently weak. Immunoblotting demonstrated a marked decrease of PiT-2 in the patient. There are few autopsy reports of IBGC patients with confirmation of the genetic background. The autopsy features seem informative for better understanding the histogenesis of IBGC lesions.

High prevalence of hyposalivation in individuals with neurofibromatosis 1: a case-control study

BACKGROUND

Neurofibromatosis type 1 (NF1) is one of the most common genetic diseases in humans and has widely variable expressivity. Oral manifestations are common, but there are no studies that investigated functional alterations in salivary glands in NF1. Our aim was to evaluate the salivary flow rate in NF1 individuals, comparing to a control group, and to investigate the possible causes and some consequences of salivary gland alteration.

METHODS

This is a case-control study that evaluated the salivary flow rate of NF1 individuals (n = 49) and compared to an age and sex-matched control group. We have also investigated the possible causes and consequences of hyposalivation in NF1 individuals through anamnesis, a specific questionnaire, physical examination, tongue coating evaluation and cytopathological exam to assess the prevalence of oral candidiasis.

RESULTS

Hyposalivation at rest was present in 59% (29/49) of NF1 individuals in contrast to 22% (11/49) in the control group, being statistically significant (P <0.0001; Wilcoxon rank-sum test). The analysis of the adjusted residual showed that the prevalence of hyposalivation in NF1 individuals (46.9%) was 4-fold higher than in controls (10.2%). None of the possible causes of hyposalivation (medications, low liquid intake, caffeinated or stimulant drink use, mouth breathers, alcohol, smoke and plexiform neurofibroma close to or involving major salivary glands areas) had important impact on the salivary flow rate in NF1 individuals.

CONCLUSIONS

Hyposalivation may be a consequence of NF1, as occurs in other genetic diseases. More studies are necessary to understand if there is and what is the relationship between NF1 and hyposalivation.

Cerebrovascular stenosis in neurofibromatosis type 1 and utility of magnetic resonance angiography: our experience and literature review

PURPOSE

Neurofibromatosis type 1 (NF1) is a multisystem autosomal dominant disorder that primarily involves the skin and the nervous system. Development of cerebral arterial stenosis is a potentially deadly complication of NF1, which is frequently underestimated. The aim of our paper is to report the frequency of this cerebrovascular disease in a series of patients affected by NF1, using magnetic resonance angiography (MRA). A review of the literature was also performed, focused on the usefulness of MRA in NF1 patients.

MATERIALS AND METHODS

Among 125 patients with NF1 (clinical diagnosis according to the standard National Institutes of Health criteria), 81 (65%) were studied with brain MRI (magnetic resonance imaging) and MRA using a 1.5 T magnet.

RESULTS

Multiple intracranial arterial stenoses were found in six patients (7.4%). In our study, MRA proved to be critical, especially for the detection of stenoses in the branches of the Circle of Willis.

CONCLUSION

Few case series have investigated the incidence of vascular complications of NF1, and most of them have used MRI. We suggest adding MRA to the brain imaging of all these patients, as stenoses of the branches of the Circle of Willis are often undetectable by MRI only.

Ablation of Rnf213 retards progression of diabetes in the Akita mouse

Moyamoya disease (MMD) and moyamoya syndrome are vasculopathies characterized by progressive stenosis in the circle of Willis and its branches. The RNF213 gene, which encodes a novel class of proteins, characterized by both E3 ligase and AAA+ATPase activities, has been identified as the susceptibility gene for MMD. However, its physiological functions remain unknown. MMD and moyamoya syndrome are often accompanied by diabetes mellitus. In this study, we generated Rnf213 knockout (KO) C57BL/6 mice (Rnf213(-/-); Ins2(+/+)), which were mated with Akita (C57BL/6 Rnf213(+/+); Ins2(+/C96Y)) mice, a strain that develops diabetes spontaneously by 5 weeks of age, to obtain mice lacking Rnf213 and carrying the Akita mutation (KO/Akita, Rnf213(-/-); Ins2(+/C96Y)). Body weight and blood glucose concentration were measured from 6 to 20 weeks. Glucose tolerance, insulin resistance, plasma insulin and leptin concentrations, food consumption, pancreatic insulin content and histopathology were evaluated at 18 weeks of age. We found that glucose tolerance, as indicated by AUC, was 20% lower (p<0.05) and insulin contents in pancreas were 150% higher (p<0.05), in KO/Akita than in Akita mice. The number of CHOP positive β-cells assayed by histopathological examination was 30% lower and food consumption was 34% lower in KO/Akita than in Akita mice (p<0.05 each). These findings indicated that the disruption of Rnf213 improved glucose tolerance by protecting islet β cells.