BETA-THALASSEMIA DISEASE PREVENTION - GENETIC MEDICINE APPLIED

Abstract

A program for thalassemia-disease prevention was evaluated, comprising education, population screening for heterozygotes and reproductive counseling; the evaluation includes cost analysis. A preprogram survey in 1978 of 3247 citizens in the high-risk communities (85% were high-school students) showed that 88% favored a program, but that only 31% considered fetal diagnosis as an acceptable option. Screening in high school or before marriage was preferred by 56%. In a 25-mo. period (Dec. 1979-Dec. 1982), 6748 persons were screened, including 5117 senior high-school students using MCV/HbA2 indices. The participation rate was 80% in the high-school group. The frequency for .beta.-thalassemia heterozygosity was 4.7% with 10-fold variation among ethnic groups at risk; the overall frequency for all variants found was 5.4%. The 60 carriers and 120 noncarriers were surveyed after screening high-school students (response rate 77%): most carries told parents (95%) and friends (67%) the test result; and 38% of the carriers'' parents (vs. 18% of the noncarriers'' parents) were also screened. Carriers would ascertain their spouses'' genotype (91%) and approved uniformly (95%) the high-school screening experience and its goal. There were 11 fetal diagnosis performed in a 25-mo. interval (> 75% participation in target population) either by fetoscopy and globin-chain analysis or by amniocentesis and genomic DNA analysis; 2 of 3 affected fetuses were aborted at parental request, there was 1 spontaneous abortion (after fetoscopy) and 7 live births. The at-risk couples claimed pregnancy would not be contemplated without the fetal-diagnosis option. Economic costs of the program were analyzed: cost/case prevented is .apprxeq. $6700, slightly less than cost-per-patient-treatment-year or about 4% of undiscounted treatment cost incurred in the first 25 yr of life for an affected individual. These findings indicate: collective acceptance of the program, appropriate attitudes among carriers, general acceptance and efficacy of fetal diagnosis and global cost-effectiveness.