Concomitant Hereditary Spherocytosis and Pyruvate Kinase Deficiency in a Spanish Family with Chronic Hemolytic Anemia: Contribution of Laser Ektacytometry to Clinical Diagnosis.

Background: Hereditary spherocytosis (HS) and pyruvate kinase deficiency (PKD) are the most common causes of hereditary chronic hemolytic anemia. Here, we describe clinical and genetic characteristics of a Spanish family with concomitant ß-spectrin (SPTB) c.647G>A variant and pyruvate kinase (PKLR) c.1706G>A variant. Methods: A family of 11 members was studied. Hematological investigation, hemolysis tests, and specific red cell studies were performed in all family members, according to conventional procedures. An ektacytometric study was performed using the osmoscan module of the Lorca ektacytometer (MaxSis. RR Mechatronics). The presence of the SPTB and PKLR variants was confirmed by t-NGS. Results: The t-NGS genetic characterization of the 11 family members showed the presence of a heterozygous mutation for the ß-spectrin (SPTB; c.647G>A) in seven members with HS, three of them co-inherited the PKLR variant c.1706G>A. In the remaining four members, no gene mutation was found. Ektacytometry allowed a clear diagnostic orientation of HS, independently from the PKLR variant. Conclusions: This family study allows concluding that the SPTB mutation, (c.647G>A) previously described as likely pathogenic (LP), should be classified as pathogenic (P), according to the recommendations for pathogenicity of the American College of Medical Genetics and the Association for Molecular Pathology. In addition, after 6 years of clinical follow-up of the patients with HS, it can be inferred that the chronic hemolytic anemia may be attributable to the SPTB mutation only, without influence of the concomitant PKLR. Moreover, only the family members with the SPTB mutation exhibited an ektacytometric profile characteristic of HS.

Red cell pyruvate kinase deficiency in Spain: A study of 15 cases. / Déficit de piruvato cinasa eritrocitaria en España: estudio de 15 casos.

BACKGROUND AND OBJECTIVE: Pyruvate kinase deficiency (PKD) is a rare, inherited disease causing chronic hemolysis and anemia of varying intensity. The genetic heterogeneity of PKD is high and, to this day, over 240 different mutations have been identified. PATIENTS AND METHODS: 15 unrelated patients affected by PKD have been studied. PKLR gene sequencing was performed by SANGER, including the determination of promoter regions, exonic, intronic flanking and 3'UTR. RESULTS: Patients were classified into 3 groups based on the intensity of their clinical symptoms: I) severe and very severe (8 patients); II) moderate (2 patients), and III) mild (5 patients). Six out of the 18 alleles found were new mutations which had not been described previously, with the PKLR c.721G>T mutation being the most prevalent (26.67%), followed by the PKLR c.1456C>T mutation (13.33%). CONCLUSIONS: In Spain, the genetic heterogeneity of PKLR is still high but differs from that observed in the previous study carried out in 1998. Total PKLR gene sequencing is necessary for the characterization of all patients with PKD and for genetic counseling.

Déficit de piruvato cinasa eritrocitaria en España: estudio de 15 casos / Red cell pyruvate kinase deficiency in Spain: A study of 15 cases

Antecedentes y objetivo: El déficit de piruvato cinasa (DPK) es una enfermedad hereditaria rara, que cursa con hemólisis crónica y anemia de intensidad variable. Su heterogeneidad genética es elevada, habiéndose descrito unas 240 mutaciones diferentes. Pacientes y metodología: Se han estudiado 15 pacientes con DPK en los que se ha secuenciado la totalidad del gen PKLR, incluyendo las regiones promotora, exónicas, intrónicas flanqueantes y 3’UTR. Resultados: Según la intensidad del cuadro clínico, los pacientes se han clasificado en 3 grandes grupos: I) grave y muy grave (8 pacientes); II) moderado (2 pacientes), y III) leve (5 pacientes). Se han identificado 18 alelos diferentes, de los que 6 son mutaciones nuevas, no descritas con anterioridad, siendo la mutación PKLRc.721G > T la más prevalente (26,67%), seguida de la mutación PKLR c.1456C > T (13,33%). Trece de los 15 pacientes mostraron un genotipo doble heterocigoto y 2 homocigoto. Conclusiones: En España, la heterogeneidad del patrón genético de la PKLR continúa siendo elevada, aunque algo diferente a la observada en un estudio anterior (1998). Se concluye que la secuenciación total del gen PKLR es imprescindible tanto para la caracterización de los pacientes como para la realización del consejo genético (AU)

Background and objective: Pyruvate kinase deficiency (PKD) is a rare, inherited disease causing chronic hemolysis and anemia of varying intensity. The genetic heterogeneity of PKD is high and, to this day, over 240 different mutations have been identified. Patients and methods: 15 unrelated patients affected by PKD have been studied. PKLR gene sequencing was performed by SANGER, including the determination of promoter regions, exonic, intronic flanking and 3’UTR. Results: Patients were classified into 3 groups based on the intensity of their clinical symptoms: I) severe and very severe (8 patients); II) moderate (2 patients), and III) mild (5 patients). Six out of the 18 alleles found were new mutations which had not been described previously, with the PKLR c.721G>T mutation being the most prevalent (26.67%), followed by the PKLR c.1456C>T mutation (13.33%). Conclusions: In Spain, the genetic heterogeneity of PKLR is still high but differs from that observed in the previous study carried out in 1998. Total PKLR gene sequencing is necessary for the characterization of all patients with PKD and for genetic counseling (AU)