PubMed · 11628748
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J Lardies González. 1981. [Not Available].. https://pubmed.ncbi.nlm.nih.gov/11628748/
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Introduction. Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease caused by the loss of the SMN1 gene, with a variable clinical spectrum determined primarily by the number of copies of the SMN2 gene. The development of new therapies underscores the importance of early molecular diagnosis and genotype-phenotype characterization. Objective. To describe 27 years of experience in the molecular diagnosis of SMA at a pediatric referral hospital in Argentina and to evaluate the correlation between SMN2 copy number and the SMA types.Population and methods. A retrospective descriptive study was conducted on 1060 pediatric patients with clinically suspected SMA who were evaluated between 1997 and 2024. Molecular diagnosis was performed using PCR-RFLP and, since 2012, MLPA to determine SMN1 and SMN2 copy number. Genotype-phenotype correlation was evaluated in 260 patients with complete clinical characterization. Results. The diagnosis was confirmed in 513 patients. A homozygous deletion of the SMN1 gene was detected in 99.6% of unrelated cases. The positivity rate increased over time. A significant correlation was observed between the number of SMN2 copies and the type of SMA, with milder phenotypes associated with a higher number of copies. Conclusion. Molecular diagnosis of SMA enabled accurate and timely characterization of patients, avoiding invasive procedures and optimizing therapeutic decision-making. Genotype-phenotype correlation is a fundamental tool for prognosis and clinical management, highlighting the importance of an interdisciplinary approach.
Tropical South America has the highest plant diversity of any region today, but this richness is usually characterized as a geologically recent development (Neogene or Pleistocene). From caldera-lake beds exposed at Laguna del Hunco in Patagonia, Argentina, paleolatitude approximately 47 degrees S, we report 102 leaf species. Radioisotopic and paleomagnetic analyses indicate that the flora was deposited 52 million years ago, the time of the early Eocene climatic optimum, when tropical plant taxa and warm, equable climates reached middle latitudes of both hemispheres. Adjusted for sample size, observed richness exceeds that of any other Eocene leaf flora, supporting an ancient history of high plant diversity in warm areas of South America.
Compared with other regions in Argentina, greater human T-cell lymphotropic virus type I (HTLV-I) seroprevalence has been reported in Jujuy Province, where it reaches 2.32% in the general population, so that a search for HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) cases deserved to be carried out. Accordingly, a clinically diagnosed and serologically confirmed cluster of cases in 1 man and 10 women, including 2 sisters, is described here. Most patients (9/11) were born in Cochinoca Department, located in an Andes highland area called Puna Jujeña, situated at more that 3400 m above sea level. No history of risk factors was disclosed, except for a single transfusion in 1 patient. In contrast to the Andean region of Bolivia, where high HTLV-I seroprevalence is in part attributable to Japanese immigrants, the Jujuy population mainly consists of aborigines, mestizos, and European descendants. Therefore, the long-term presence of virus in Jujuy natives may be taken for granted. Considering the HAM/TSP cluster described here plus previously reported isolated cases in neighboring Salta Province, we speculate that the Puna Jujeña region and regions in that vicinity would be a microepidemic focus of disease. To determine the role of possible pathogenic cofactors such as geographic, ethnic, genetic, and cultural features, further pertinent surveys are required in subtropical northwestern Argentina.