Retrospective analysis of 17 patients with mitochondrial membrane protein-associated neurodegeneration diagnosed in Russia.

INTRODUCTION: Mitochondrial membrane protein-associated neurodegeneration (MPAN) is a rare neurological syndrome caused by pathogenic variants in the C19orf12 and is characterized by iron deposition in the basal ganglia and substantia nigra. Only a limited number of cohort studies were published to date and the prevalence of MPAN remains uncertain. METHODS: Recruited subjects with MPAN in Russia were diagnosed by whole-exome sequencing or Sanger sequencing of the C19orf12 gene. Data of over 14000 whole exome sequencing analyses was used to calculate the estimated disease frequency. RNA analysis was performed by RT-PCR. QSVanalyzer software was used to quantify the allelic disbalance. RESULTS: We describe the clinical and molecular characterizations of 17 patients with MPAN. DNA analysis detected three previously undescribed pathogenic/likely pathogenic variants in the C19orf12 gene. The estimated disease frequency was calculated to be 1:619150. We describe unusual clinical observations in several cases. One patient showed severe neurogenic muscle weakness along with a lack of marked spasticity or optic nerve atrophy. In another mild clinical case with the NM_001031726.3:c.204_214del (p.(Gly69Argfs*10)) variant in a heterozygous state, a marked allelic disbalance was observed on the RNA level with reduced expression level of the wild-type allele. Thus, this case became the first one of a possible regulatory variant causing MPAN. CONCLUSION: We reported a detailed clinical and molecular characterization of the third-largest MPAN cohort. We expanded the mutational and clinical spectrum of MPAN. Moreover, we calculated the estimated MPAN frequency in the Russian population for the first time.

Prenatal diagnosis of Norrie disease after whole exome sequencing of an affected proband during an ongoing pregnancy: a case report.

BACKGROUND: Hereditary ophthalmic pathology is a genetically heterogeneous group of diseases that occur either as an isolated eye disorder or as a symptom of hereditary syndromes (chromosomal or monogenic). Thus, a diagnostic search in some cases of ophthalmic pathology can be time- and cost-consuming. The most challenging situation can arise when prenatal diagnosis is needed during an ongoing pregnancy. CASE PRESENTATION: A family was referred to the Research Centre for Medical Genetics (RCMG) for childbirth risk prognosis at 7-8 week of gestation because a previous child, a six-year-old boy, has congenital aniridia, glaucoma, retinal detachment, severe psychomotor delay, and lack of speech and has had several ophthalmic surgeries. The affected child had been previously tested for PAX6 mutations and 11p13 copy number variations, which revealed no changes. Considering the lack of pathogenic changes and precise diagnosis for the affected boy, NGS sequencing of clinically relevant genes was performed for the ongoing pregnancy; it revealed a novel hemizygous substitution NM_000266.3(NDP):c.385G > T, p.(Glu129*), in the NDP gene, which is associated with Norrie disease (OMIM #310600). Subsequent Sanger validation of the affected boy and his mother confirmed the identified substitution inherited in X-linked recessive mode. Amniotic fluid testing revealed the fetus was hemizygous for the variant and lead to the decision of the family to interrupt the pregnancy. Complications which developed during the termination of pregnancy required hysterectomy due to medical necessity. CONCLUSIONS: Clinical polymorphism of hereditary ophthalmic pathology can severely complicate establishment of an exact diagnosis and make it time- and cost-consuming. NGS appears to be the method-of-choice in complicated cases, and this could substantially hasten the establishment of a diagnosis and genetic risk estimation.

Comparative analysis of methods to increase the amount of keratinized mucosa before stage-two surgery: a randomized controlled study.

OBJECTIVES: The aim of the present randomized controlled clinical trial was to evaluate the outcomes of the use of free gingival graft (FGG), of a collagen matrix and of vestibuloplasty to increase the amount of keratinized attached mucosa (KM) before healing abutment placement. METHOD AND MATERIALS: The study was a randomized, parallel-group controlled investigation. All patients were treated to increase the KM width before placement of implant-supported prostheses. The implants were placed 3 to 6 months before the interventions. Three techniques were tested: an apically positioned flap (control group), FGG (test group 1), and use of a collagen matrix (test group 2). Biopsy was performed during healing abutment placement by means of a mucotome. RESULTS: A total of 63 patients were recruited and treated, and 58 were available for follow-up visits. After 4 weeks, the KM width gain was 1.93 ± 0.85 mm, 4.85 ± 1.11 mm, and 3.03 ± 0.58 mm, respectively, for control group, test group 1, and test group 2. Postoperative pain was significantly higher in the FGG group than in the others. Edema and hyperemia decreased gradually during the first week without significant differences among groups. CONCLUSION: Despite the limitations of the study, it was found that FGG was the most effective technique to augment the amount of KM in sites of implant placement. The use of a collagen matrix could be a viable alternative to diminish the intervention's impact on patients' postoperative quality of life.

Peculiarities of RBCs resistance to acid hemolysis in hibernating mammals.

The binding of acids and alkalis, formed in tissues by metabolism, along with oxygen and CO(2) transport are recognise as the principal functions of red blood cells (RBCs). Decreases in internal environment pH may result in activation of potential endogenous cytotoxic metabolites, OH and oxidant formation and, as a consequence, result in oxidative damage of cell membrane leading to hemolysis. The characteristics of acid hemolysis in hibernating mammals have been determined in this study. Parameters of HCl-hemolysis, such as the average time for RBC hemolysis and the population distribution of the response, have been investigated. Measurements were performed within 40-5 degrees C temperature range. The resistance of hibernator RBCs to increased acidity, determined according to the acid hemolysis parameters, was found to reflect whether the animal was in the summer active period or in hibernation, with differences also apparent at different points with the hibernation season itself. It was demonstrated that hemolysis parameters of naturally cold-tolerant organisms are altered by decreases in temperature. We discuss a role of cytoskeletal-membrane interactions as a fast-acting switch of the structural and functional state of hibernator RBCs as an adaptation mechanism to acidosis arising from hypothermia and hypermetabolism.

Thermally induced transformation of mammalian red blood cells during hyperthermia.

The structural and transport characteristics of membranes are mainly determined by the state of the cytoskeleton. The characteristic changes in morphology of human (adult donor and cord) and rat Red Blood Cells (RBC) and of their membrane, induced by hyperthermia (46-51 degrees C) have been analyzed. Two different types of morphological changes have been observed to take place during hyperthermia in all studied RBC groups. We have observed either formation and exfoliation of spiculas from membrane, resulting in the formation of large (4-5 microm) sphere-like cell body and small (0.5-1.5 microm) vesicles or cell fragmentation with formation of large (3-3.5 microm) vesicles. The two distinct phenomena are likely to be determined by the heterogeneity of the RBC population in terms of cell age. There was noted the difference of cord RBC from the donor ones in temperature value of transformation beginning, as well as the character of deformation and vesicle formation, that may testify to their less thermoresistance. The ultrastructure of the membrane, studied with the freeze-fracturing technique, testifies to an irreversible character of membrane changes. The aggregation of intramembrane particles (IMPs) as a continuous network testifies to the strengthening of the interactions between denatured spectrin and bilayer integral components.