Diagnóstico pré-natal de défice em proteína trifuncional mitocondrial / Prenatal diagnosis of mitochondrial protein trifunctional deficiency

O diagnóstico pré-natal de doenças hereditárias dometabolismo permite aos casais de risco equacionarem assuas opções reprodutivas de modo a só terem descendentesnão afectados. No caso de défice em proteína trifuncionalmitocondrial (MIM #6090015) ou MPT (complexo multienzimáticoessencial à β-oxidação dos ácidos gordos de cadeialonga de C12 a C18) essa situação reveste-se de grandeimportância dada a elevada letalidade associada à patologia.Os autores apresentam um caso clínico de défice em proteínatrifuncional fatal. O diagnóstico pré-natal (DPN) foidisponibilizado em três gestações, sendo os dois primeirospor doseamento enzimático e o último através de estudomolecular(AU)

The prenatal diagnosis of inherited metabolic diseaseoffers, to at-risk couples, the opportunity to plan theirreproductive options in order to have only unaffectedoffspring.In cases of mitochondrial protein trifunctional deficiency(MIM #6090015) or MPT (multienzyme complexinvolved in the β-oxidation of fatty acids with lengths ofC12-C18) this is an important issue because a high rateof mortality is associated with this disorder.The authors report a neonatal fatal case of MPT deficiency.Prenatal diagnosis was offered in the following 3pregnancies: two by a biochemical approach and the lastone by mutational analysis(AU)

[Proteasome degradation of protein C and plasmin inhibitor mutants: molecular mechanism of congenital protein deficiency].

In many inherited disorders, protein deficiency is one of the major aetiologies, but the molecular and cellular mechanisms remain unclear. We investigated the intracellular degradation of mutant proteins, using naturally occurring PC and PI mutants that lead to congenital deficiencies. We have shown that proteasomes are very important for the degradation of PC and PI mutants, irrespective of the presence or absence of N-glycosylation moieties. Furthermore, mannose trimming after glucose removal is very important for initiation of the degradation. Inhibition of glucose trimming of the mutant proteins accelerated degradation by the proteasomes, and initiation of the degradation occurs after mannose trimming of the middle chain of N-linked glycosylation by mannosidase I. The binding of molecular chaperons influenced by the presence of N-glycosylation moieties may affect the efficient degradation of the mutant proteins. Cotransfection of endoplasmic reticulum (ER) degradation enhancing alpha-mannosidase like protein (EDEM) accelerated the degradation of N-glycosylated PC. The mutant PC or PI molecules were ubiquitin-independently degraded by proteasomes. Autophagy does not appear to contribute to the degradation of PC and PI mutants. These findings might help to elucidate the molecular mechanisms and potential treatments of congenital deficiencies of proteins in a system of coagulation and fibrinolysis.

Activator protein 1-mediated transcriptional regulation strategy sustains long-term expression of a xenogeneic gene product in vivo: an implication for gene therapy targeting congenital protein deficiencies.

Maintenance of high-level transgene expression is the main challenge in current gene therapy. Although the cytomegalovirus (CMV) promoter/enhancer or its derivative the CAG promoter has been harnessed in current gene therapy vectors, transgene expression by these vectors is often transient and remains at suboptimal levels due to undefined mechanisms, possibly including the shortage of transcriptional machinery. To overcome this drawback, we designed a novel transcriptional control system, designated here as transcription factor-supercharging promoter system, in which transgene expression is regulated by the positive feedback circuit consisting of cis- and trans-acting elements of gene expression machinery. Among combinations of these elements, a plasmid composed of a target gene expression cassette driven by the chimeric CMV promoter containing repetitive 12-O-tetradecanoylphorbol-13-acetate-responsive elements as cis-acting elements (CMV-TTT) and expression cassettes for c-Fos and c-Jun genes as trans-acting elements facilitated high and long-term (>10 months) expression of a transgene after its intramuscular electroporation-mediated delivery in mice. Since human secretory alkaline phosphatase was used as a reporter, it was suggested that the immune evasion mechanism elicited by the CMV-TTT and/or c-Fos/ c-Jun expression also contributed to the sustained expression in mice. Our strategy may open a new avenue for a gene therapy that involves lifelong supplementation of a deficient protein that could be targeted by the host's immune system.

Homozygous protein C deficiency: early treatment with warfarin.

We present a case of homozygous protein C deficiency with neonatal purpura fulminans and disseminated intravascular coagulopathy (DIC) starting shortly after birth. In addition, the infant had vitreal eye hemorrhages and intraparenchymal brain infarction, apparently as intrauterine events. Within 15 hours of institution of fresh frozen plasma (FFP) infusions the DIC resolved and the progression of purpura fulminans reversed. Warfarin (0.4 mg/kg/day) was started on the fifth day of life, followed by gradual tapering of the FFP infusions. There were no recurrences of purpura, areas of skin necrosis healed without the need for skin grafting, and the areas of brain infarction resolved without apparent sequelae. The eye and brain lesions may be intrauterine events and appear to be a regular feature of this syndrome. Family studies are essential to establish the diagnosis, although there may be no family history of thromboembolic events, as in this case. Homozygous protein C deficiency is a rare disorder, but one in which early recognition and intervention may be lifesaving. Ours is the youngest patient yet reported to be treated with warfarin anticoagulation. We were thus able to avoid the complications of long-term plasma therapy as well as the potential thrombotic complications of central venous catheter placement.

Transient ischemic attack in a patient with congenital protein-C deficiency during treatment with stanozolol.

A patient with congenital protein-C deficiency was treated with stanozolol for 8 weeks to increase circulating levels of protein C. A rise in protein C was achieved, accompanied by an increase in factor II, factor X, antithrombin III, and protein S; but at the 8th week the patient suffered a transient ischemia attack.

[Congenital protein C deficiency and thromboembolic diseases]. / Kongenitaler Protein-C-Mangel und thromboembolische Erkankungen.

Besides its cofactor protein S and antithrombin III, protein C is one of the most important inhibitors of plasma coagulation. In seven members of a family as well as in three further unrelated patients, a congenital protein C deficiency with thromboembolic diseases including a coumarin necrosis was observed in two cases. Deficiency of protein C predisposes to the occurrence of thromboembolism, but the severity of the underlying heterozygotic genetic defect can also vary within the family. Long-term oral anticoagulation with phenprocoumon is the therapy of choice. Genetic counselling should always be carried out.

Ontogeny of the levels of serotonin in various parts of the brain in severely protein malnourished rats.

We have previously reported that irreversible central and peripheral chemical changes and irreversible changes in spontaneous activity of single neurons in the frontal cortex are seen in adult rats who were born to mothers fed an 8% isocaloric casein diet 5 weeks before mating and during gestation, who were cross-fostered at birth by control (25% casein diet fed) dams and who showed a normal growth curve. Thus, in the rat, a normal growth curve does not necessarily mean a normal development. We now report similar irreversible, albeit larger, changes in small-for-gestational-age (SGA) rats born to mothers fed a 6% isocaloric diet, nursed by 6% casein fed dams and who showed an abnormal growth curve. The regional ontogeny of serotonin, tryptophan and 5-HIAA in the brain and plasma levels of tryptophan, protein, albumin and NEFA are reported. Thus, similar changes were observed in animals with a normal growth curve and in animals with a very markedly decreased growth curve resembling marasmus in humans.

Visual discrimination in rats: the effects of rehabilitation following intergenerational malnutrition.

The effect of rehabilitation following intergenerational malnutrition in rats was observed using 3 tests of visual discrimination (Lashley tests). The following groups were studied at 3 months of age: animals nutritionally deprived of protein for many generations (intergenerational malnutrition), those from the same stock rehabilitated for 1 to 2 generations at an adequate protein level, and controls from a stock never exposed to malnutrition. Males rehabilitated for 2 generations showed some improvement in performance in the Lashley tests, but did not attain the level of well-nourished controls. In agreement with the earlier data, females were less susceptible to behavioral deficits from intergenerational malnutrition and recovery was observed after 1 generation of rehabilitation. Growth of both males and females rehabilitated for 1 or 2 generations was superior to that of control rats.