Limb-girdle muscular dystrophy type 2B (LGMD2B) and Miyoshi myopathy (MM) are autosomal recessive disorders caused by mutations in the dysferlin gene on chromosome 2p13. The authors studied a large Russian family with both LGMD2B and MM. All affected individuals, as well as one preclinical boy with dystrophic changes on muscle biopsy, were found to be homozygous for a novel dysferlin mutation, TG573/574AT (Val67Asp). This finding supports the view that additional factors (e.g., modifier genes) contribute to the phenotypic expression of causative mutations in dysferlinopathies.
We describe a unique six-generation, highly consanguineous family originating from an isolated mountainous village in the Russian province of Daghestan. Three separate clinical phenotypes of progressive muscular dystrophy were identified in this large family. Seven patients developed a classical limb-girdle variant of muscular dystrophy (LGMD), with disease onset at 15-30 years and loss of ambulation within a 25-year course. The second group included three patients with a slowly progressive distal myopathy first manifested in the late teens and confined to the tibial and calf muscles. Each of these two phenotypes segregated independently as an autosomal recessive trait, and muscle biopsies showed non-specific myopathic changes. Lastly, two male siblings exhibited an atypical variant of Duchenne muscular dystrophy confirmed by detection of a deletion in the dystrophin gene. To clarify the molecular basis of the polymorphic autosomal recessive form of muscular dystrophy in this kindred, we performed molecular genetic studies on 67 family members and obtained significant evidence for linkage to chromosome 2p. A maximum pairwise lod (logarithm of odds) score of 5.64 was achieved at the zero recombination fraction (i.e. at theta = 0.00) for locus D2S291; multipoint linkage analysis confirmed the most likely location of a mutant gene near D2S291. The patients with LGMD and those with the distal muscular dystrophy phenotype share a common affected homozygous haplotype associated with the same founder chromosome; key recombinants defined D2S286 and D2S292 to be the closest loci flanking the mutant gene. Remarkably, two clinically distinct forms of autosomal recessive muscular dystrophy, LGMD type 2B (LGMD2B) and Miyoshi myopathy, were recently mapped to the same locus. We suggest that all three chromosome 2p-linked conditions may represent allelic disorders, i.e. different phenotypic expressions of a single gene.
Parkinson's disease (PD) is a systemic neurodegenerative disease characterized by tremor, rigidity, bradykinesia, and stooping posture. When more than 60% of dopaminergic neurons in the substantia nigra of the brain have died, motor symptoms manifest in PD. Currently, oxidative stress (OS) is considered to be one of the leading factors provoking death of dopaminergic neurons in PD. This review is concerned with the role of polyamines in PD, especially focusing on their role in OS induction. Polyamines (putrescine, cadaverine, spermidine and spermine) are involved in many molecular mechanisms, including cell proliferation and differentiation, gene transcription and translation, modulation of the functional activity of ion channels and receptors, and other vital processes. It is worth noting that under physiological conditions polyamines are antioxidants. It has been shown that spermine oxidase (SMOX) is up-regulated in PD, activating polyamine breakdown, which leads to excessive formation of toxic aldehydes (such as acrolein), H 2 O 2 (a strong cytostatic) and ammonia (a toxic substance). Polyamines are also involved in the pathogenetic mechanism of α-synuclein modification resulting in the formation of Lewy bodies. This review provides data on the changes in polyamine levels at later stages of the disease. The review also examines the role of polyamines, as gliotransmitters, in regulating neural function and vice versa. The mechanisms of polyamine "pumping" from neurons to glia can be considered factors of OS regulation in neurons. Prolonged accumulation of polyamines in glia can lead to oxidation of polyamines and therefore potentially to gliosis in PD. The exact mechanisms of this process are, however, not clear. Answering the questions regarding the role of polyamines in gliosis development and pathogenesis of PD is necessary for treating cognitive impairment in patients with PD, which is particularly important.
Therapeutic efficacy of the plant neuroprotector Phytomix-40 in Parkinson's disease was demonstrated. This preparation consists of the components from extracts of 40 plants, including some adaptogens (ginseng, eleutherococcus, Rhodiola rosea, etc.). The preparation normalized immune, antioxidant, and hormonal parameters in patients. The neuroprotective plant adaptogen can be used in complex therapy for Parkinson's disease for improving its efficacy.
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