[Late onset Pompe disease: an analysis of 19 patients from Mexico]. / Enfermedad de Pompe de inicio tardío: análisis de una casuística de 19 pacientes mexicanos.

INTRODUCTION: Pompe disease (PD) is a rare metabolic myopathy with an ample and heterogeneous clinical spectrum, particularly late onset PD (LOPD), which is characterized by appearance at older age and slower disease progression, leading to diagnostic confirmation difficulty and delay. AIM: To describe the genotype and clinical characteristics of Mexican patients with LOPD. MATERIAL AND METHODS: Clinical information from 19 Mexican patients with LOPD confirmed with enzyme activity and GAA gene analysis was reviewed. Genetic information of our population was crossed with international genetic databases. RESULTS: Median age between onset of symptoms and diagnosis was 19 years (range 2-43) and diagnostic confirmation 36 years (range 9-52). Most frequently referred symptoms were proximal axial weakness (n = 17; 89.5%), waddling gait (n = 17; 89.5%) and hyperlordosis (n = 7; 36.8%). Sixteen patients (84.2%) were evaluated with electromyography; a myopathic pattern was reported in 11 (57.8%), but only in 5 patients (26%) paraspinal muscle evaluation was included. The most pathogenic mutations in our group were c.-32-13T>G, c.1799G>A and c.1082C>T. CONCLUSIONS: Similar to other international publications, LOPD in Mexico is clinically heterogeneous; patients may delay years before diagnosis is established. Axial and proximal weakness is the most frequent clinical feature; thus, electromyography with paraspinal muscle evaluation is essential. Except for one, the mutations found in our patients have been previously reported in PD genetic databases.

TITLE: Enfermedad de Pompe de inicio tardío: análisis de una casuística de 19 pacientes mexicanos.Introducción. La enfermedad de Pompe es una miopatía metabólica rara con espectro clínico heterogéneo, especialmente la de inicio tardío, cuya sintomatología es de progresión más lenta y representa un gran reto diagnóstico. Objetivo. Describir el genotipo y las características clínicas de pacientes mexicanos con Pompe de inicio tardío (LOPD). Material y métodos. Se incluyó a 19 pacientes mexicanos con LOPD confirmada mediante actividad enzimática y estudio molecular del gen GAA. Se evaluaron datos clínicos y se revisaron las mutaciones en bases de datos genómicas. Resultados. La mediana de edad de inicio de los síntomas fue de 19 años (rango: 2-43 años), y la edad de diagnóstico, de 36 años (rango: 9-52 años). Los síntomas más frecuentes fueron debilidad axial y proximal (n = 17; 89,5%), marcha basculante (n = 17; 89,5%) e hiperlordosis (n = 7; 36,8%). A 16 pacientes (84,2%) se les realizó electromiografía; 11 (57,8%) describieron patrón miopático y sólo en cinco pacientes (26%) se incluyó la valoración de los músculos paraespinales. Las variantes patogénicas más frecuentes en nuestra casuística fueron c.-32-13T>G, c.1799G>A y c.1082C>T. Conclusiones. Parecido a lo comunicado en publicaciones internacionales, la LOPD en México es clínicamente heterogénea; los pacientes pueden tardar años en llegar al diagnóstico. La debilidad muscular axial y proximal es el dato clínico más frecuente, por lo que la electromiografía debe incluir valoración de los músculos paraespinales. A excepción de una, las mutaciones encontradas en nuestra serie de casos se encuentran previamente descritas en las bases de datos de enfermedad de Pompe.

Genetic and clinical characterization of 73 Pigmentary Mosaicism patients: revealing the genetic basis of clinical manifestations.

BACKGROUND: Pigmentary mosaicism constitutes a heterogeneous group of skin pigmentation alterations associated with multisystem involvement. The aim of this study was to establish a complete cytogenetic and molecular characterization of PM patients, emphasizing on searching for possible low chromosomal mosaicism and on establishing an accurate genotype-phenotype correlation. RESULTS: A total of 73 patients were included (3 months to 18 years of age), 52% male and 48% female. Observed in 69 (95%) patients, the most frequent pattern of pigmentation was fine and whorled BL, which was associated with disseminated skin extent in 41 (59%) patients. Central nervous system (84%) alterations were the most frequent observed in the group of patients, followed by the musculoskeletal (53%) and ophthalmologic (27%) alterations. Considering the pattern of pigmentation, no significant differences in association with skin extent or extracutaneous manifestations were detected. Following a strict cytogenetic analysis strategy, screening metaphases from three different tissues (peripheral blood, hyperpigmented and hypopigmented skin) we found that 23/73 patients had chromosomal abnormalities classified as follows: 1) Mosaic with 2 or more different cell lines with structural alterations n = 19; 2) Polyploidy (mosaic) n = 1 and 3) Alterations in all cells in three different tissues n = 3. SNP array, array CGH and FISH were useful for the complete characterization of the chromosomal aberrations, for the detection of microdeletions in patients with normal karyotype but with strong clinical suspicious of chromosomal alteration, and for a better establishment of genotype-phenotype correlation. In 2 patients we found genes associated with some of the extracutaneous manifestations (SHH, MNX1, PPP2R2C). CONCLUSIONS: This group of 73 patients finely described is the largest series of patients with pigmentary mosaicism reported worldwide. As we showed in this study, the followed analysis strategy allowed the detection of cytogenetic and molecular abnormalities, and made possible the establishment of genotype-phenotype associations in some patients. An important limitation of our study was the analysis of fibroblasts cultures instead of melanocytes and keratinocytes. In some cases the direct molecular DNA analysis of skin biopsy could be another choice.