The Phenotypic Spectrum of Spinocerebellar Ataxia Type 19 in a Series of Latin American Patients.

Spinocerebellar ataxia 19 (SCA19) represents a rare autosomal dominant genetic disorder resulting in progressive ataxia and cerebellar atrophy. SCA19 is caused by variants in the KCND3 gene, which encodes a voltage-gated potassium channel subunit essential for cerebellar Purkinje cell function. We describe six cases from Chile and Mexico, representing the largest report on SCA19 in Latin America. These cases encompass a range of clinical presentations, highlighting the phenotypic variability within SCA19 from an early-onset, severe disease to a late-onset, slowly progressive condition with normal lifespan. While some patients present with pure ataxia, others also show cognitive impairment, dystonia, and other neurological symptoms. The correlations between specific KCND3 variants and phenotypic outcomes are complex and warrant further investigation. As the genomic landscape of spinocerebellar ataxias evolves, comprehensive genetic testing is becoming pivotal in improving diagnostic accuracy. This study contributes to a better understanding of the clinical spectrum of SCA19, laying the groundwork for further genotype-phenotype correlations and functional studies to elucidate the underlying pathophysiology.

[Cryoglobulinemic vasculitis due to hyperviscosity and cryogel formation as the onset of multiple myeloma. Report of one case]. / Vasculitis crioglobulinémica por hiperviscosidad y formación de criogel como debut de mieloma múltiple. Caso clínico.

Multiple Myeloma (MM) is characterized by a clonal expansion of plasma cells in the bone marrow. These cells typically produce a monoclonal immunoglobulin, and its symptoms arise either from plasma cell infiltration in several organs, or secondary to the presence of a monoclonal protein peak. Symptoms can be summarized by the acronym CRAB (hypercalcemia, renal failure, anemia and bone lesions). Sometimes, in the setting of a protein secreting monoclonal gammopathy, formation of cryoglobulins develops. Cryoglobulins are plasma proteins that precipitate at low temperatures, forming a cold - induced precipitate at small vessels, causing a wide range of clinical manifestations. We report a female consulting for ulcers lasting 2 months in the left foot associated with purpuric lesions in both lower limbs. Protein electrophoresis showed a monoclonal peak in the gamma region. Bone marrow aspirate showed 27% of plasma cells with kappa chain restriction by cytometry. The presence of cryoglobulins was confirmed. The patient was treated with dexamethasone and bortezomib, with a progressive healing of lower limb lesions and disappearance of cryoglobulins. She was discharged in good conditions.

Complex Networks and the b-Value Relationship Using the Degree Probability Distribution: The Case of Three Mega-Earthquakes in Chile in the Last Decade.

Studies from complex networks have increased in recent years, and different applications have been utilized in geophysics. Seismicity represents a complex and dynamic system that has open questions related to earthquake occurrence. In this work, we carry out an analysis to understand the physical interpretation of two metrics of complex systems: the slope of the probability distribution of connectivity (γ) and the betweenness centrality (BC). To conduct this study, we use seismic datasets recorded from three large earthquakes that occurred in Chile: the Mw8.2 Iquique earthquake (2014), the Mw8.4 Illapel earthquake (2015) and the Mw8.8 Cauquenes earthquake (2010). We find a linear relationship between the b-value and the γ value, with an interesting finding about the ratio between the b-value and γ that gives a value of ∼0.4. We also explore a possible physical meaning of the BC. As a first result, we find that the behaviour of this metric is not the same for the three large earthquakes, and it seems that this metric is not related to the b-value and coupling of the zone. We present the first results about the physical meaning of metrics from complex networks in seismicity. These first results are promising, and we hope to be able to carry out further analyses to understand the physics that these complex network parameters represent in a seismic system.

Multilocus inherited neoplasia allele syndrome: report of uncommon combinations between CHEK2/ATM and BRCA1/CDKN2A genes.

Background: Multilocus inherited neoplasia allelic syndrome (MINAS) is a recently coined term that describes the coexistence of two or more pathogenic variants (PVs) in cancer susceptibility genes (CSGs) in a single individual. Case presentation: This article presents two cases of MINAS due to rare CSG combinations. The first was a 37-year-old woman carrying PVs in the mutated ataxia telangiectasia (ATM) and CHEK2 genes, with HER-2 positive unilateral breast cancer at 29. The second was a 53-year-old woman carrying PVs in the BRCA1 and CDKN2A genes, who presented with triple-negative breast cancer at 51. We describe their family history and treatment, where the lack of evidence for personalised management becomes evident. Conclusion: Predicting the phenotypic effect of harbouring two variants in CSG is challenging. It is essential to encourage the notification of other cases and carry out functional studies to establish specific risks for affected individuals to develop personalised follow-up guidelines to reduce the associated morbimortality.

Variants in BRCA1/2 in a hospital-based cohort in Chile and national literature review.

Purpose: The aim was to assess the diagnostic yield of next generation sequencing (NGS) multi-gene panels for breast and ovarian cancer in a high-complexity cancer centre in Chile. Additionally, our goal was to broaden the genotypic spectrum of BRCA variants already identified in Chilean families. Methods: Retrospective analysis was conducted on the genetic test results of 722 individuals from Fundación Arturo López Pérez's genetic counselling unit between 2016 and 2021. A comprehensive literature review encompassing articles analysing the frequency of germinal pathogenic variants in BRCA1/2 within the Chilean population was undertaken. Results: 23.5% of the panels had positive results, with 60% due to pathogenic variants in the BRCA1/2 genes. Seven previously unreported variants in BRCA1 from Chilean studies were identified.One or more variants of uncertain significance were detected in 31% of the results, and 11.5% of the families in this cohort presented copy number variants (CNVs) in BRCA1/2.8 studies analysed the frequency of pathogenic variants in BRCA1/2 in the Chilean population between 2006 and 2023, with a frequency between 7.1% and 17.1%.51 BRCA1 variants in 149 families have been reported in Chile and 38 BRCA2 variants in 132 families. Nine founder pathogenic variants identified by one study were present in 51.9% of the total Chilean families reported. Conclusion: Our findings advocate for the integration of NGS multi-gene panel testing as a primary strategy within our population. This approach allows for the comprehensive assessment of single nucleotide variants and CNVs in BRCA1/2, alongside other high and moderately penetrant genes associated with breast and ovarian cancer.

Vasculitis crioglobulinémica por hiperviscosidad y formación de criogel como debut de mieloma múltiple. Caso clínico / Cryoglobulinemic vasculitis due to hyperviscosity and cryogel formation as the onset of multiple myeloma. Report of one case

Multiple Myeloma (MM) is characterized by a clonal expansion of plasma cells in the bone marrow. These cells typically produce a monoclonal immunoglobulin, and its symptoms arise either from plasma cell infiltration in several organs, or secondary to the presence of a monoclonal protein peak. Symptoms can be summarized by the acronym CRAB (hypercalcemia, renal failure, anemia and bone lesions). Sometimes, in the setting of a protein secreting monoclonal gammopathy, formation of cryoglobulins develops. Cryoglobulins are plasma proteins that precipitate at low temperatures, forming a cold - induced precipitate at small vessels, causing a wide range of clinical manifestations. We report a female consulting for ulcers lasting 2 months in the left foot associated with purpuric lesions in both lower limbs. Protein electrophoresis showed a monoclonal peak in the gamma region. Bone marrow aspirate showed 27% of plasma cells with kappa chain restriction by cytometry. The presence of cryoglobulins was confirmed. The patient was treated with dexamethasone and bortezomib, with a progressive healing of lower limb lesions and disappearance of cryoglobulins. She was discharged in good conditions.