INTRODUCTION:Cystic fibrosis is a multisystem autosomal recessive disease with wide variability in clinical severity. It is incurable and characterized by elevated and premature mortality, as well as poor quality of life. Its frequency, lethality and devastating impact on both the physical and psychological wellbeing of patients and their families, make it a serious health problem. Its frequency in Cuba is 1 in 9862 live births, where marked molecular heterogeneity of the CFTR gene makes molecular diagnosis difficult. Six mutations have been identified that together enable molecular characterization of only 55.5% of cystic fibrosis chromosomes. This paper presents national results of antenatal diagnostic testing, using direct and indirect methods, for detection of cystic fibrosis. OBJECTIVE: Characterize the Cuban public health system's experience with antenatal molecular testing for cystic fibrosis from 1988 through 2011. METHODS: A retrospective descriptive study was conducted with results of antenatal diagnostic testing of amniotic fluid, performed nationwide from 1988 through 2011, for 108 fetuses of couples with some risk of having children affected by cystic fibrosis, who requested testing. Polymerase chain reaction detected mutations p.F508del, p.G542X, p.R1162X, p.R334W, p.R553X and c.3120+1G>A, and markers XV2C and KM19. Data were analyzed using absolute frequencies and percentages, and presented in tables. RESULTS: For 93 cases (86.1%), testing for cystic fibrosis was done using direct analysis of mutations p.F508del, p.G542X, p.R1162X, p.R334W, p.R553X and c.3120+1G>A; five cases (4.6%) were tested indirectly using markers XV2C/Taq I and KM19/Pst I; and 10 (9.3%) were tested using a combination of the two methods. A total of 72 diagnoses (66.7% of studies done) were concluded, of which there were 20 healthy fetuses, 16 affected, 27 carrier, and 9 who were either healthy or carriers of an unknown mutation. CONCLUSIONS: Direct or indirect molecular study was successfully used in over half of antenatal tests requested by couples throughout Cuba at risk of having children affected by cystic fibrosis, which is of great social value because of CF's burden on affected persons and their families.

Wilson’s disease is a hereditary disorder of autosomal recessive inheritance that can cause irreversible, potentially lethal lesions to liver and brain. Its molecular cause is the appearance of mutations in the atp7b gene. A total of 379 different disease-producing mutations are currently known, turning the molecular diagnosis of this disorder into a formidable challenge. The present study used single-strand conformational polymorphism for the detection of conformational changes in exon 8 of this gene. Two shifts distinct from the normal allele, denominated b and c, were detected and mapped to mutations L708P and 2304DupC in heterozygosis. Allelic frequencies for these mutations in 72 Cuban Wilson’s disease patients were 2 and 0.7%, respectively.

La enfermedad de Wilson es un trastorno hereditario que se transmite con un patrón de herencia autosómico recesivo. Puede provocar lesiones irreversibles en el hígado y el cerebro, que pueden llevar a la muerte. Su causa molecular son las mutaciones en el gen atp7b con 379 variantes promotoras de la enfermedad. El diagnóstico molecular es complejo. En este estudio se empleó la técnica de polimorfismo conformacional de simple cadena para la determinación de cambios conformacionales en el exón 8 de ese gen. Se detectaron dos cambios distintos de la variante normal, denominados: b y c, los cuales correspondieron a las mutaciones L708P y 2304DupC en estado heterocigótico, respectivamente. Las frecuencias alélicas de tales mutaciones en 72 pacientes cubanos con la enfermedad de Wilson son de 2 y 0.7%, respectivamente.

Hemophilia is a congenital disease of coagulation disorder and it is a recessive disorder linked to X-chromosome. The molecular study is conducted by indirect studies due to it is caused by heterogeneous mutations in gen of FVIII and FIX in 40 families with hemophilia A (HA) and 10 with hemophilia B (HB). DNA extraction was carried out by saline precipitation method in 293 blood samples and 19 samples of amniotic fluid, as well as the analysis of St14, Bcl I and Hind III polymorphism for the AH and Taq I, Xmn I and Dde I for BH. The PCR technique was used. In the caser of AH it was possible to achieve a 35 % of information for St14 and Hind III and a 32.5 % for Bcl. Dde polymorphism supplied more information for BH for a 33 %; whereas the Taq I represented the 10 % of information and Xmn I the 0 %. We verified that from the families analyzed with HA, in 23 of them we there was information. Besides, in 4 families affected by HB there was information. A total of 19 prenatal diagnoses were made with a previous determination of fetus sex, including 3 males ill.

La hemofilia se caracteriza por ser una enfermedad congénita del trastorno de la coagulación y constituye un desorden recesivo ligado al cromosoma X. El estudio molecular se realiza por estudios indirectos por ser causada por mutaciones heterogéneas en los genes del FVIII y FIX. Se realizó el estudio de 40 familias afectadas con hemofilia A (HA) y 10 hemofilia B (HB). La extracción de ADN se realizó por el método de precipitación salina a 293 muestras de sangre y 19 de líquido amniótico, y se hizo el análisis de los polimorfismos St14, Bcl I y Hind III para la HA y Taq I, Xmn I y Dde I para la HB. Se usó la técnica de PCR. En el caso de la HA se obtuvo el 35 % de informatividad para St14 y Hind III y 32,5 para Bcl 1. El polimorfismo Dde I fue el más informativo para la HB con el 33 %; mientras que Taq I representó el 10 % de informatividad y XmnI el 0 %. Se comprobó que de las 40 familias analizadas con HA, 23 fueron informativas. Por otra parte, fueron informativas 4 familias de las afectadas con HB. Se realizaron 19 diagnósticos prenatales con previa determinación del sexo fetal, incluidos 3 varones enfermos.