Mitochondria-lysosome membrane contacts are defective in GDAP1-related Charcot-Marie-Tooth disease.

Mutations in the GDAP1 gene cause Charcot-Marie-Tooth (CMT) neuropathy. GDAP1 is an atypical glutathione S-transferase (GST) of the outer mitochondrial membrane and the mitochondrial membrane contacts with the endoplasmic reticulum (MAMs). Here, we investigate the role of this GST in the autophagic flux and the membrane contact sites (MCSs) between mitochondria and lysosomes in the cellular pathophysiology of GDAP1 deficiency. We demonstrate that GDAP1 participates in basal autophagy and that its depletion affects LC3 and PI3P biology in autophagosome biogenesis and membrane trafficking from MAMs. GDAP1 also contributes to the maturation of lysosome by interacting with PYKfyve kinase, a pH-dependent master lysosomal regulator. GDAP1 deficiency causes giant lysosomes with hydrolytic activity, a delay in the autophagic lysosome reformation, and TFEB activation. Notably, we found that GDAP1 interacts with LAMP-1, which supports that GDAP1-LAMP-1 is a new tethering pair of mitochondria and lysosome membrane contacts. We observed mitochondria-lysosome MCSs in soma and axons of cultured mouse embryonic motor neurons and human neuroblastoma cells. GDAP1 deficiency reduces the MCSs between these organelles, causes mitochondrial network abnormalities, and decreases levels of cellular glutathione (GSH). The supply of GSH-MEE suffices to rescue the lysosome membranes and the defects of the mitochondrial network, but not the interorganelle MCSs nor early autophagic events. Overall, we show that GDAP1 enables the proper function of mitochondrial MCSs in both degradative and nondegradative pathways, which could explain primary insults in GDAP1-related CMT pathophysiology, and highlights new redox-sensitive targets in axonopathies where mitochondria and lysosomes are involved.

Genetic determinants of aromatase inhibitor-related arthralgia: the B-ABLE cohort study.

A major side effect of aromatase inhibitor (AI) therapy is AI-related arthralgia (AIA), which often leads to therapy discontinuation. We aimed to identify genetic variants associated with AIA and therapy discontinuation in the first year of AI treatment. Our prospective cohort study included 343 postmenopausal women with early breast cancer starting AI therapy. Single nucleotide polymorphisms (SNPs) in candidate genes involved in estrogen and vitamin D signaling were selected. Univariate and multivariate linear/logistic regressions were fitted in order to asses the association between studied SNPs and AIA intensity (visual analogic scale score) at 3 and 12 months of follow-up, worsening pain, and therapy discontinuation. We also tested for a priori-defined interactions by introducing multiplicative terms in the regression equations. SNPs in CYP17A1 and VDR genes appeared significantly associated with AIA (P = 0.003, P = 0.012, respectively). One SNP in CYP27B1 gene was related to therapy discontinuation [P = 0.02; OR 0.29 (0.09-0.99)]. We revealed interactions between CYP27B1 and both CYP17A1 (P = 0.01) and VDR SNPs (P = 0.06). Furthermore, an additive effect on pain intensity was shown for unfavorable alleles, with two points higher mean absolute pain increase and up to 5.3-fold higher risk of worsening pain compared to favorable genotypes. SNPs in CYP17A1, VDR, and CYP27B1 genes predict the risk of AIA. Their determination would be useful to trigger the monitoring strategies in women at risk of therapy discontinuation.

Translational Diagnostics: An In-House Pipeline to Validate Genetic Variants in Children with Undiagnosed and Rare Diseases.

Diagnosis is essential for the management and treatment of patients with rare diseases. In a group of patients, the genetic study identifies variants of uncertain significance or inconsistent with the phenotype; therefore, it is urgent to develop novel strategies to reach the definitive diagnosis. Herein, we develop the in-house Translational Diagnostics Program (TDP) to validate genetic variants as part of the diagnostic process with the close collaboration of physicians, clinical scientists, and research scientists. The first 7 of 33 consecutive patients for whom exome-based tests were not diagnostic were investigated. The TDP pipeline includes four steps: (i) phenotype assessment, (ii) literature review and prediction of in silico pathogenicity, (iii) experimental functional studies, and (iv) diagnostic decision-making. Re-evaluation of the phenotype and re-analysis of the exome allowed the diagnosis in one patient. In the remaining patients, the studies included either cDNA cloning or PCR-amplified genomic DNA, or the use of patients' fibroblasts. A comparative computational analysis of confocal microscopy images and studies related to the protein function was performed. In five of these six patients, evidence of pathogenicity of the genetic variant was found, which was validated by physicians. The current research demonstrates the feasibility of the TDP to support and resolve intramural medical problems when the clinical significance of the patient variant is unknown or inconsistent with the phenotype.

Hemangioma fusocelular. Presentación de un caso y revisión de la literatura

El hemangioma fusocelular es un tumor vascular benigno poco frecuente. Se ha relacionado con el síndrome de Maffucci, el síndrome de Klippel-Trenaunay y otras malformaciones venosas. Habitualmente son nódulos dérmicos de color violáceo en las extremidades distales de niños y adultos jóvenes, sin predilección por ningún sexo. Se presenta el caso de una paciente de 22 años que padecía un nódulo subcutáneo, doloroso a la presión, en la pierna derecha. A la exploración física se observó una tumoración redondeada violácea de 1,5 cm. Se sospechó la presencia de un hemangioma. Se realizó una escisión simple y se envió al departamento de anatomía patológica. Se describió la muestra como nódulo intraluminal constituido por una proliferación de células de aspecto fusiforme con moderada atipia y aisladas figuras de mitosis y se confirmó el diagnóstico de hemangioma fusocelular de localización intravascular. El diagnóstico del hemangioma fusocelular es anatomopatológico y como tratamiento suele bastar la escisión simple, aunque frecuentemente recidivan. Dado que el hemangioma fusocelular es una entidad poco conocida y puede ser confundida con otras lesiones vasculares, se considera interesante la comunicación del presente caso. El conocimiento de este tipo de lesión puede aumentar los casos notificados.

Spindle cell hemangioma is a rare benign vascular tumor. It has been linked to Maffucci syndrome, Klippel-Trenaunay syndrome, and other venous malformations. They are usually purplish dermal nodules on the distal extremities of children and young adults, with no sex predilection. A case of a 22-years-old patient who suffered from a subcutaneous nodule, painful on pressure, in the right leg is presented. On physical examination, a 1.5 cm violaceous round tumor was observed. The presence of a hemangioma was suspected. A simple excision was performed and sent to the pathology department. The sample was described as an intraluminal nodule made up of a proliferation of spindle-shaped cells with moderate atypia and isolated mitotic figures, and the diagnosis of intravascular spindle cell hemangioma was confirmed. The diagnosis of spindle cell hemangioma is anatomopathological and simple excision is usually sufficient as treatment, although they frequently recur. Since spindle cell hemangioma is a little-known entity and can be confused with other vascular lesions, the communication of this case is considered interesting. Knowledge of this type of injury can increase reported cases.

SNPs in bone-related miRNAs are associated with the osteoporotic phenotype.

Biogenesis and function of microRNAs can be influenced by genetic variants in the pri-miRNA sequences leading to phenotypic variability. This study aims to identify single nucleotide polymorphisms (SNPs) affecting the expression levels of bone-related mature microRNAs and thus, triggering an osteoporotic phenotype. An association analysis of SNPs located in pri-miRNA sequences with bone mineral density (BMD) was performed in the OSTEOMED2 cohort (n = 2183). Functional studies were performed for assessing the role of BMD-associated miRNAs in bone cells. Two SNPs, rs6430498 in the miR-3679 and rs12512664 in the miR-4274, were significantly associated with femoral neck BMD. Further, we measured these BMD-associated microRNAs in trabecular bone from osteoporotic hip fractures comparing to non-osteoporotic bone by qPCR. Both microRNAs were found overexpressed in fractured bone. Increased matrix mineralization was observed after miR-3679-3p inhibition in human osteoblastic cells. Finally, genotypes of rs6430498 and rs12512664 were correlated with expression levels of miR-3679 and miR-4274, respectively, in osteoblasts. In both cases, the allele that generated higher microRNA expression levels was associated with lower BMD values. In conclusion, two osteoblast-expressed microRNAs, miR-3679 and miR-4274, were associated with BMD; their overexpression could contribute to the osteoporotic phenotype. These findings open new areas for the study of bone disorders.

AI-related BMD variation in actual practice conditions: A prospective cohort study.

The aim of the study was to evaluate the progression of bone mineral density (BMD) during 3 years of aromatase inhibitors (AI) therapy in actual practice conditions. This prospective, clinical cohort study of Barcelona-Aromatase induced Bone Loss in Early breast cancer (B-ABLE) assessed BMD changes during 3 years of AI treatment in women with breast cancer. Patients with osteoporosis (T score < -2.5 or T score ≤ -2.0) and a major risk factor and/or prevalent fragility fractures were treated with oral bisphosphonates (BPs). Of 685 women recruited, 179 (26.1%) received BP treatment. By the third year of AI therapy, this group exhibited increased BMD in the lumbar spine (LS; 2.59%) and femoral neck (FN; 2.50%), although the increase was significant only within the first year (LS: 1.99% and FN: 2.04%). Despite BP therapy, however, approximately 15% of these patients lost more than 3% of their baseline bone mass. At 3 years, patients without BP experienced BMD decreases in the LS (-3.10%) and FN (-2.79%). In this group, BMD changes occurred during the first (LS: -1.33% and FN: -1.25%), second (LS: -1.19% and FN: -0.82%), and third (LS: -0.57% and FN: -0.65%) years of AI treatment. Increased BMD (>3%) was observed in just 7.6% and 10.8% of these patients at the LS and FN, respectively. Our data confirm a clinically relevant bone loss associated with AI therapy amongst nonusers of preventative BPs. We further report on the importance of BMD monitoring as well as calcium and 25-hydroxy vitamin D supplementation in these patients.

Esteatocistoma solitario de cuero cabelludo / Solitary steatocystoma of the scalp

El esteatocistoma es un hamartoma quístico de la porción media de las unidades folículo sebáceas que afecta principalmente el ducto sebáceo. Comúnmente se encuentra de manera múltiple y se transmite en forma autosómica dominante; en algunos casos se presenta en un contexto no familiar y en otros puede ser solitario. La primera descripción del esteatocistoma múltiple (EM) muy probablemente corresponde a Jamieson en 1873. La forma solitaria de esteatocistoma fue descrito por primera vez en 1982 por Brownstein y existen pocos casos descritos en la literatura Presentamos un caso clínico de paciente varón joven con tumoración solitaria en cuero cabelludo que fue extirpado cuyo resultado histopatológico fue de esteatocistoma solitario.

Steatocystoma is a cystic hamartoma of the middle portion of the sebaceous follicular units that mainly affects the sebaceous duct. It commonly presents in multiple forms and is transmitted in an autosomal dominant manner; in some cases, it occurs in a non-familial context and in others it may be solitary. The first description of steatocystoma multiplex (MS) is most likely by Jamieson in 1873. The solitary form of steatocystoma was first described in 1982 by Brownstein and there are few cases described in the literature. We present a clinical case of a young male patient with a solitary tumor on the scalp that was excised and whose histopathological result was solitary steatocystoma.

Skeletal adverse effects with aromatase inhibitors in early breast cancer: evidence to date and clinical guidance.

Aromatase inhibitors (AIs) are routinely used in the adjuvant treatment of women with hormone receptor-positive early breast cancer. Patients who receive AIs have an increased risk of bone loss and arthralgia compared with those treated with tamoxifen. In addition to the effects of AIs, the population of women with early breast cancer has a high prevalence of 25-hydroxyvitamin D (25(OH)D) insufficiency. In our experience 88% of patients had concentrations lower than 30 ng/ml. Vitamin D supplementation should be adapted to the baseline concentration. Another relevant finding in our research program was the close relationship between 25(OH)D levels and intensity of AI-related arthralgia (AIrA). A target concentration of 40 ng/ml 25(OH)D may prevent development of AIrA. We also demonstrate that AIrA is genetically determined: single nucleotide polymorphisms located in genes encoding key factors for the metabolism of estrogens and vitamin D (CYP17A1, VDR, and CYP27B1) are associated with self-reported arthralgia during AI therapy. We recommend establishing an individualized protocol of bone-health surveillance based on baseline and evolutionary clinical variables.

Analyses of RANK and RANKL in the post-GWAS context: functional evidence of vitamin D stimulation through a RANKL distal region.

Over the past decade, many genome-wide association studies (GWAs) and meta-analyses have identified genes and regions involved in osteoporotic phenotypes. Nevertheless, the large majority of these results were not tested at any functional level. GWA-associated single-nucleotide polymorphisms (SNPs) near candidate genes such as RANK and RANKL suggest that these SNPs and/or other variants nearby may be involved in bone phenotype determination. This study focuses on SNPs along these two genes, which encode proteins with a well-established role in the bone remodeling equilibrium. Thirty-three SNPs, chosen for their location in evolutionary conserved regions or replicated from previous studies, were genotyped in the BARCOS cohort of 1061 postmenopausal women and tested for association with osteoporotic phenotypes. SNP rs9594738, which lies 184 kb upstream of the RANKL gene, was the only SNP found to be associated with a bone phenotype (dominant model: beta coefficient = -0.034, p = 1.5 × 10(-4) , for lumbar spine bone mineral density). Functional experiments exploring a distal region (DR) of 831 bp that harbors this SNP in a centered position (nt 470) demonstrated its capacity to inhibit the RANKL promoter in reporter gene assays. Remarkably, this DR inhibition was significantly reduced in the presence of vitamin D. In conclusion, the GWA-associated SNP rs9594738 lies in a region involved in transcription regulation through which vitamin D could be regulating RANKL expression and bone mineral density.