TREM-2 is an immunoglobulin-like cell surface receptor associated with DAP12/KARAP that activates monocyte-derived dendritic cells (DCs) in vitro. Recently, it has been shown that genetic defects of human DAP12/KARAP and TREM-2 result in a rare syndrome characterized by bone cysts and presenile dementia called Nasu-Hakola disease. This observation suggests that TREM-2 may function in myeloid cells other than DCs, most probably osteoclasts (OCs) and microglial cells, which are involved in bone modeling and brain function. Consistent with this prediction, here we show that OC differentiation is dramatically arrested in TREM-2–deficient patients, resulting in large aggregates of immature OCs that exhibit impaired bone resorptive activity. These results demonstrate a critical role for TREM-2 in the differentiation of mononuclear myeloid precursors into functional multinucleated OCs.

Background: Although physical rehabilitation is commonly administered to MS patients, its efficacy has not been established. Objective: We assessed the efficacy of an inpatient physical rehabilitation program on impairment, disability, and quality of life of MS patients with a randomized, single-blind, controlled trial. Methods: Fifty ambulatory MS patients were assigned to 3 weeks of inpatient physical rehabilitation (study treatment) or exercises performed at home (control treatment). Patients were evaluated at baseline and at 3, 9, and 15 weeks by a blinded examining physician. Results: No changes in impairment occurred in either group, as measured by the Expanded Disability Status Scale. At the end of the intervention the study group improved significantly in disability, as assessed by the Functional Independence Measure (FIM) motor domain, compared with controls (p = 0.004), and the improvement persisted at 9 weeks (p = 0.001). The effect size statistic was usually large or moderate in all scale scores of the FIM motor domain at 3 weeks and moderate to fair thereafter. The study group also improved in overall health-related quality of life profile compared with controls; however, the difference was significant only for the mental composite score at 3 (p = 0.008) and 9 weeks (p = 0.001). Conclusions: Despite unchanging impairment, physical rehabilitation resulted in an improvement in disability and had a positive impact on mental components of health-related quality of life perception at 3 and 9 weeks.

Alexander disease (AD) in its typical form is an infantile lethal leucodystrophy, characterized pathologically by Rosenthal fibre accumulation. Following the identification of glial fibrillary acidic protein (GFAP) gene as the causative gene, cases of adult-onset AD (AOAD) are being described with increasing frequency. AOAD has a different clinical and neuroradiological presentation with respect to early-onset AD, as abnormalities are mainly concentrated in the brainstem–spinal cord junction. We report detailed clinical and genetic data of 11 cases of AOAD, observed over a 4-year period, and a review of the previously reported 25 cases of genetically confirmed AOAD. In our series, onset occurred as late as age 62, and up to 71 in an affected deceased relative. Most cases appeared sporadic, but family history may be misleading. The most frequent symptoms were related to bulbar dysfunction—with dysarthria, dysphagia, dysphonia (seven patients)—, pyramidal involvement (seven patients) and cerebellar ataxia (seven patients). Four patients had palatal myoclonus. Sleep disorders were also observed (four cases). Bulbar symptoms, however, were infrequent at onset and two symptomatic patients had an almost pure pyramidal involvement. Two subjects were asymptomatic. Misdiagnosis at presentation was frequent and MRI was instrumental in suggesting the correct diagnosis by showing, in all cases, mild to severe atrophy of the medulla oblongata extending caudally to the cervical spinal cord. In ten patients, molecular studies revealed six novel missense mutations and three previously reported changes in GFAP. The last typical patient carried no definitely pathogenic mutation, but a missense variant (p.D157N), supposedly a rare polymorphism. Revision of the literature and the present series indicate that the clinical picture is not specific, but AOAD must be considered in patients of any age with lower brainstem signs. When present, palatal myoclonus is strongly suggestive. Pyramidal involvement, cerebellar ataxia and urinary disturbances are common. Less frequent findings include sleep disorders and dysautonomia. Fluctuations may occur. The course is variable, usually slowly progressive and less severe than the AD forms with earlier onset. AOAD is more common than previously thought and might even be the most common form of AD. The diagnosis is strongly suggested by MRI and confirmed by GFAP gene analysis.