Hb Costa Rica or alpha 2 beta 2 77(EF1)His --> Arg: the first example of a somatic cell mutation in a globin gene.

We have identified a minor hemoglobin component (approximately 5%) in the blood of a healthy Costa Rican female, but not in her mother and two brothers (father not studied), that has an His --> Arg replacement at position beta 77 (Hb Costa Rica). No other amino acid replacements were observed and no beta- or gamma-chain-like peptides were present. Hb Costa Rica has abnormal stability. Sequence analyses of numerous polymerase chain reaction (PCR)-amplified segments of DNA that contain exon 2 of the beta gene failed to identify a CAC --> CGC (His --> Arg) mutation. The same was the case when cDNA was sequenced, indicating that a beta-Costa Rica-mRNA could not be detected with this procedure. Gene mapping of genomic DNA with Bg/II, BamHI, and HindIII gave normal fragments only and with the same intensity as observed for the fragments of a normal control. The quantities of the beta chain variants Hb J-Iran and Hb Fukuyama with related mutations at beta 77 vary between 30% and 45% in heterozygotes, whereas that of Hb F-Kennestone with the same His --> Arg mutation but in the G gamma-globin gene, is a high 40%-45% (as percentage of total G gamma) in a heterozygous newborn. These different observations exclude a heterozygosity of the A --> G mutation at codon beta 77, as well as a deletion comparable to that of Hbs Lepore or Kenya, or a beta-globin gene duplication, and point to a nontraditional inheritance of Hb Costa Rica. Allele-specific amplification of cDNA with appropriate primers identified the presence of a low level of mutated mRNA in the reticulocytes of the patient, which was confirmed by dotblot analysis of the same material with 32P-labeled probes. Comparable amplification products were not observed in genomic DNA. The A --> G mutation apparently occurred in a somatic cell at a relatively early stage in the development of the hematopoietic cell system, and Hb Costa Rica accumulated through rapid cell divisions in patchy areas in the bone marrow (somatic mosaicism). An unequal distribution of Hb Costa Rica over the red cells supports this possibility.

Mutation analysis of glucose-6-phosphate dehydrogenase (G6PD) variants in Costa Rica.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency has previously been reported among both the black and white populations of Costa Rica. All 28 G6PD A- samples were found to be of the common G6PD A-376G/202A type. A previously described mutation associated with nonspherocytic hemolytic anemia, G6PD Puerto Limón, was found to be due to a G----A transition at nucleotide (nt) 1192, causing a glu----lys substitution. Mutations in this region of the G6PD molecule seem invariably to be associated with chronic hemolytic anemia. G6PD Santamaria had been described previously in two unrelated white subjects. We found that both did, indeed, have the same mutations. In this variant the A----G substitution at nt 376 that is characteristic of G6PD A was present, but an A----T mutation at nt 542, apparently superimposed on the ancient G6PD A mutation, resulted in an asp----val substitution. Thus, the gain of a negative charge at amino acid 126 was counterbalanced by the loss of a charge at amino acid 181, giving rise to a variant with the G6PD A mutation but with normal electrophoretic mobility.

[Chronic non-spherocytic hemolytic anemia caused by pyruvate kinase deficiency in a Costa Rican family carrying hemoglobin C disease]. / Anemia hemolítica crónica no esferocítica (AHCNE) por déficit de piruvato quinasa (PK) en una familia costarricense portadora de hemoglobinopatía C.

The two first homozygous (or double heterozygous) cases of pyruvate kinase (PK) deficiency found in a Costa Rica family with no signs of consanguinity are reported. The clinical manifestations of the deficiency were present in both cases, these being enhanced in one of them by pregnancy. The family study performed showed the heterozygous character of the PK deficiency in all cases, plus the demonstration in two instances (father and brother) of a heterozygous haemoglobin C disease. The importance of the PK/HK quotient in the identification of the PK deficiency heterozygous is stressed, especially when the enzyme activity registered from haemolysates falls within the normal range.

[Hereditary persistence of fetal Hb and its association with Hb S. 1st case found in Costa Rica]. / Persistencia hereditaria de Hb fetal y su asociación con Hb S. Primer caso hallado en Costa Rica.

An electrophoretic pattern of Hb S + Hb F, the relative concentration of this last being 37%, was found in a phenotypically mestizo 3 year-old child of Costa Rica. The genotype of the child was G gamma/A gamma, with a ratio of 1:1. Both hereditary alterations were disperse, according to the family study performed, which showed Hb S plus hereditary persistence of foetal haemoglobin of the African type G gamma A gamma (delta beta o). This case is briefly discussed, along with the molecular heterogeneity of HPFH and the importance of the differential diagnosis of electrophoretic patterns found in Hb S + Hb F patients.

A glucose-6-phosphate dehydrogenase variant, Gd(-) Santamaria found in Costa Rica.

Red cell glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-chromosomal-linked abnormality often associated with hemolytic anemia. The G6PD variants obtained from 2 unrelated males, one associated with enzyme deficiency and history of hemolytic jaundice, and the other associated with enzyme deficiency but no hemolytic problems, were examined. Although the 2 subjects have no known consanguinity, the two enzymes could not be distinguished from each other in respect to their electrophoretic mobilities and kinetic properties, both exhibiting slower than normal anodal electrophoretic mobility, lower Km for G6P and NADP and higher rate of utilization of 2-deoxy-G6P and deamino-NADP. An unique double-banded pattern was observed in starch gel electrophoresis at pH 7.0 and pH 8.6. The variant is distinguished from all reported Gd variants, and it is designated Gd(-) Santamaria.

Hemoglobinometria.Normalizacion de la metodologia. Preparacion nacional del estandar de calibracion y de hemolizado control. / Hemoglobinometry.Standardization of the methodology.National preparation of the standard of calibration and hemolized control

Se indican las caracteristicas esenciales del metodo de la HiCN para la medicion cuantitativa de Hb. Se hace ver la importancia del diluente de Van Kampen y Zijestra (VKZ), para tales efectos y la aplicabilidad de las soluciones patron para la calibracion de los fotometros. En detalle se especifica la preparacion nacional del patron concentrado de HiCN (CIANO-CIHATA)y del hemolizado control (HEMOCIHATA).Finalmente se propone un practico programa de control de calidad y se indica un colorario sobre los errores sistematicos en los que se puede incurrir en la hemoglobinometria

G6PD-Puerto Limón: a new deficient variant of glucose-6-phosphate dehydrogenase associated with congenital nonspherocytic hemolytic anemia.

A new glucose-6-phosphate dehydrogenase (G6PD) variant with total deficiency associated with congenital nonspherocytic hemolytic anemia was found in a Costa Rican family. The study of the partially purified enzyme revealed thermal instability, increased G6P affinity, abnormal pH optimum, increased utilization of analogues, and a chromatographic behavior that differs from all the variants previously described. Thus, this new variant was designated G6PD Puerto Limón.

Anemia refractaria sideroblastica idiopatica (IRSA). (Primera de dos partes). / Idiopathic refractory sideroblastic anemia (IRSA). (First of two parts)

Es esta una revision de la literatura mas importante para caracterizar la anemia refractaria sideroblastica ideopatica (IRSA), en sus aspectos morfologicos, bioquimicos y citoquimicos. Se hace enfasis a la existencia de una doble poblacion celular, en las tres lineas medulares. Se discuten las principales teorias etiopatogenicas, a saber: causas extramedulares, defectos en la sintesis del heme y origenes malignos de la enfermedad. Se exponen tambien algunos datos sobre la polemica que alrededor de IRSA se ha sucitado, en cuanto a su nomenclatura y caracterizacion

Cuantificacion de haptoglobinas sericas por un metodo modificado de peroxidacion. / Serum haptoglobins quantification by modified peroxidation method

Con el deseo de preconizar un metodo sencillo y de bajo costo para cuantificar haptoglobinas sericas, se tomo de referencia el de la peroxidacion de Owen et al, estableciendo una serie de experimentos que lo hacen mas practica para su uso rutinario en cualquier laboratorio. Dentro de las principales modificaciones introducidas se encuentran la mayor estabilidad de los reactivos, el uso de un estandar primario de CNMHb, la correccion de los valores encontrados cuando se procesan muestras con clara evidencia de hemolisis espuria, el caracter de micrometodo y una estandarizacion sencilla que permite el uso de la curva de calibracion hasta por un mes luego de establecida

Anemia refractaria sideroblastica idiopatica (IRSA) (segundo de dos partes). / Idiopathic refractary sideroblastic anemia (IRSA) (second of two parts)

Pareciera que la anemia refractaria sideroblastica idiopatica (IRSA) es un cambio maligno, no invasivo y con frecuencia preleucemico. Algunos pacientes desarrollan otros tipos de neoplasias y desordenes hematologicos. Se revisa la literatura reciente mas importante al respecto, y algunos conceptos sobre la posible mutacion de la celula germinativa comun, que origina estos cambios. Se detallan las manifestaciones clinicas sobresalientes que presentan los pacientes con IRSA, haciendo hincapie en la cronicidad y posible malignidad de la enfermedad. Se menciona lo sombrio del pronostico y lo dificil del manejo de los enfermos

Escrutinio de hemoglobinopatias y G6PD en una poblacion italiana radicada en Costa Rica. / Detection of hemoglobinopathies and G6PD in a italian population radicated in Costa Rica

En una poblacion de origen italiano que radica en el canton de Coto Brus, Puntarenas, se pudo detectar la presencia de dos casos de beta-tal menor en 64 individuos estudiados. Para el escrutinio y caracterizacion definitiva del fenotipo talasemico se siguio con protocolos ampliamente estudiados en el CIHATA. No se encontro ningun caso deficiente en G6PD ni la presencia de Hbs anormales