PLP1 and GPM6B intragenic copy number analysis by MAPH in 262 patients with hypomyelinating leukodystrophies: identification of one partial triplication and two partial deletions of PLP1

The proteolipid protein 1 (PLP1) gene is known to be mutated in the X-linked disorders of myelin formation Pelizaeus–Merzbacher disease (PMD) and spastic paraplegia type 2. The most commonly found PLP1 mutations are gene duplications (60–70%) and point mutations (20%). About 20% of patients with a PMD phenotype do not present identified PLP1 mutation, thus suggesting genetic heterogeneity and/or undetected PLP1 abnormalities. Except the recently described MLPA screening the seven exonic regions, the currently used techniques to quantify PLP1 gene copy number do not investigate small intragenic PLP1 rearrangements. Using the multiplex amplifiable probe hybridization (MAPH) technique, we looked simultaneously for intragenic rearrangements along the PLP1 gene (exonic and regulatory regions) and for rearrangements in the GPM6B candidate gene (a member of the proteolipid protein family). We tested 262 hypomyelinating patients: 56 PLP1 duplicated patients, 1 PLP1 triplicated patient, and 205 patients presenting a leukodystrophy of undetermined origin with brain MRI suggesting a defect in myelin formation. Our results show that MAPH is an alternative reliable technique for diagnosis of PLP1 gene copy number. It allows us (1) to demonstrate that all PLP1 duplications previously found encompass the whole gene, (2) to establish that copy number changes in GPM6B and intragenic duplications of PLP1 are very unlikely to be involved in the etiology of UHL, and (3) to identify one partial triplication and two partial deletions of PLP1 in patients presenting with a PMD phenotype.     

Gender differences in retention rate of tumor necrosis factor alpha inhibitor treatment in ankylosing spondylitis: a retrospective cohort study in daily practice

Aim

To assess gender differences in ankylosing spondylitis (AS) patients in relation to tumor necrosis factor alpha inhibitor (TNFi) drug survival and occurrence of adverse events in daily practice in a large peripheral hospital.

Method

Retrospective data were collected from AS patients treated with etanercept, infliximab and adalimumab between January 2004 and January 2014. Kaplan–Meier survival curves were conducted to describe the drug survival and occurrence of adverse events in time.

Results

Overall, 122 AS patients (60.7% male) were included over a 10‐year time period, with a mean treatment period of 51 months (1–127 months). In total, 21 (17.2%) patients stopped the TNFi, mainly due to inefficacy (52.4%). Female patients showed a significant shorter treatment period compared to males (33.4 vs. 44.9 months). In addition, female patients switched more between TNFi compared to males (26.9% vs. 16.3%) and had a significantly higher risk at developing infections compared to male patients (26% vs.19%).

Conclusion

Females stayed on the same TNFi for a significantly shorter period compared to males (33.4 vs. 44.9 months) and the most important reason to stop or switch the drug was inefficacy. Moreover, females seemed to be more prone to infections during TNFi treatment than males.     

Rapid exhaustion of auditory neural conduction in a prototypical mitochondrial disease,Friedreich ataxia

Objectives

In patients with Friedreich ataxia (FRDA), mitochondrial failure leads to impaired cellular energetics. Since many FRDA patients have impaired hearing in noise, we investigated the objective consequences on standard auditory brainstem-evoked responses (ABRs).

An in vivo and in vitro model of Plasmodium falciparum rosetting and autoagglutination mediated by varO, a group A var gene encoding a frequent serotype

In the Saimiri sciureus monkey, erythrocytes infected with the varO antigenic variant of the Plasmodium falciparum Palo Alto 89F5 clone bind uninfected red blood cells (rosetting), form autoagglutinates, and have a high multiplication rate, three phenotypic characteristics that are associated with severe malaria in human patients. We report here that varO parasites express a var gene having the characteristics of group A var genes, and we show that the varO Duffy binding-like 1α₁ (DBL1α₁) domain is implicated in the rosetting of both S. sciureus and human erythrocytes. The soluble varO N-terminal sequence (NTS)-DBL1α₁ recombinant domain, produced in a baculovirus-insect cell system, induced high titers of antibodies that reacted with varO-infected red blood cells and disrupted varO rosettes. varO parasites were culture adapted in vitro using human erythrocytes. They formed rosettes and autoagglutinates, and they had the same surface serotype and expressed the same varO gene as the monkey-propagated parasites. To develop an in vitro model with highly homogeneous varO parasites, rosette purification was combined with positive selection by panning with a varO NTS-DBL1α₁-specific mouse monoclonal antibody. The single-variant, clonal parasites were used to analyze seroprevalence for varO at the village level in a setting where malaria is holoendemic (Dielmo, Senegal). We found 93.6% (95% confidence interval, 89.7 to 96.4%) seroprevalence for varO surface-reacting antibodies and 86.7% (95% confidence interval, 82.8 to 91.6%) seroprevalence for the recombinant NTS-DBL1α₁ domain, and virtually all permanent residents had seroconverted by the age of 5 years. These data imply that the varO model is a relevant in vivo and in vitro model for rosetting and autoagglutination that can be used for rational development of vaccine candidates and therapeutic strategies aimed at preventing malaria pathology.     

Difficulties in diagnosing group o human immunodeficiency virus type 1 acute primary infection

We report a rare case of acute human immunodeficiency virus (HIV) type 1 group O infection in a French Caucasian woman. Her sexual partner was secondarily diagnosed with HIV infection, and transmission was confirmed by phylogenetic analysis. The unequal performance of many of the serologic and molecular assays commercially available leads to delays in diagnosis and affects patient management.     

Human tooth culture: a study model for reparative dentinogenesis and direct pulp capping materials biocompatibility

In a previous work, based on an in vitro entire tooth culture model of human immature third molars, we demonstrated that perivascular progenitor cells can proliferate and migrate to the injury site after pulp exposure. In this work, we investigated the differentiation of cells after direct capping with biomaterials classically used in restorative dentistry. Histological staining after direct pulp capping with Calcium Hydroxide XR(R) or MTA revealed early and progressive mineralized foci formation containing BrdU-labeled sequestered cells. The molecular characterization of the matrix and the sequestered cells by immunohistochemistry (Collagene type I, Dentin sialoprotein, and Nestin) clearly demonstrates that these areas share common characteristics of the mineralized matrix of reparative dentin formed by odontoblast-like cells. This reproduces some features of the pulp responses after applying these materials in vivo and demonstrates that the entire tooth culture model reproduces a part of the early steps of dentin regeneration in vivo. Its future development may be useful in studying the effects of biomaterials on this process.     

Sirenomelia as a part of VACTERL association: a study of three cases

Sirenomelia, characterized by a fusion of lower limb buds, is rare. Moreover, the coexistence of this malformation with a VACTERL sequence is exceptional. We report, here, three new observations associating these two diseases on fetuses from 14 to 26 weeks gestation. With these three new cases associating sirenomelia and VACTERL, observed in our unit and examined in light of data from the medical literature, we discuss the embryologic origin of such malformations and the nosologic frontiers between these two diseases.