No abstract

Background: Mutations in the genes PRKN and LRRK2 are the most frequent known genetic lesions among Parkinson's disease patients. We have previously reported that in the Portuguese population the LRRK2 c.6055G > A; p.G2019S mutation has one of the highest frequencies in Europe.

Pompe disease is a rare metabolic disorder with available enzymatic replacement therapy. Contrasting with the classic infantile form, the others subtypes have a heterogeneous presentation that makes an early and accurate diagnosis difficult. We conducted a prospective, multicenter, observational study to identify undiagnosed patients. During a one-year period, patients followed in Portuguese neuromuscular outpatient clinics with proximal muscle weakness affecting upper and/or lower limbs, hyperCKemia in two or more determinations or hypotonia and hyperCKemia, were screened for acid α-glucosidase deficiency by dried blood spots. Lysosomal acid-alpha-1,4-glucosidase activity was determined by tandem mass spectrometry and positive results were confirmed by molecular study. From the 99 patients screened, Pompe disease was confirmed in 4, with age of onset ranging from 2.5 to 48 years, all with limb girdle muscle weakness, corresponding to a frequency of 4% in our cohort and 4.9% of limb girdle muscle weakness. Screening for Pompe disease in high risk populations, using dried blood spots, was already performed in some European populations. Apart from two negative Scandinavian studies, positive cases were confirmed in 2.8-7.9% of patients presenting with limb girdle muscle weakness and in 0-2.5% with isolated hyperCKemia.

Parvovirus B19 (PB19) is a common, widespread, small, single-stranded DNA virus which has been linked with a broad spectrum of clinical illnesses, including a variety of neurological complications such as encephalitis, meningitis, myelitis, stroke, cerebellar ataxia, and neuropathy. The authors describe a case of PB19 infection associated with hemolytic anemia and cranial polyneuropathy involving the second and third cranial nerves in a 23-year-old immunocompetent woman. The diagnosis of acute PB19 infection was established with detection of positive DNA and anti-PB19 IgM antibodies in blood samples. Antiganglioside antibody studies were performed and serum anti-GD1b IgG was strongly positive. Further investigation was normal or negative, excluding other infectious or autoimmune disorders. The patient was initially treated with a 5-day course of intravenous immunoglobulin (IGIV). Because of incomplete neurological recovery, methylprednisolone was also administered 7 days after IGIV therapy initiation. Complete resolution of clinical symptoms was observed 3 months after disease onset at follow-up visit, despite the persistence of PB19 DNA and anti-PB19 IgM antibodies in serum 5 months after the initial presentation. Our report provides evidence that PB19 could affect both the central and peripheral nervous system, possibly by triggering an autoimmune mechanism that leads to autoantibody production.