The author’s experience of 20 years as director of the medical genetic services program in Cuba is presented. The setting of the infrastructure for equipment and the training of personnel for the medical genetic program began in 1981 in the city of Havana, and was progressively extended to cover the whole country in 1988. Between 1982 and 2002, 2.8 million pregnant women were tested for sickle cell carrier status, 96,000 carriers and 4,786 couples at risk were detected and offered genetic counseling and prenatal diagnosis. In the same period, the combination of maternal serum α-fetoprotein screening and fetal ultrasound led to the prenatal diagnosis of anomalies in several thousand fetuses. The accessibility to legal abortion, and the autonomous decisions by the majority of couples to terminate abnormal pregnancies reduced the prevalence of neural tube defects and sickle cell disease at birth by 90 and 65%, respectively, by 2002. In the span of approximately 20 years, 22,690 pregnant women at risk received prenatal chromosomal diagnosis. Newborn screening for phenylketonuria and congenital hypothyroidism was established. Genetic counseling was offered to every detected person or family at risk for genetic conditions. The network of medical genetic services established in the country received a very positive acceptance by the population. A very successful connection with the primary health care level was established.

The identification of disease genes using family-based approaches has provided important insights into the pathogenesis of Parkinson's disease (PD) demonstrating the importance of genetic studies on monogenic forms of the disease. We studied a large Cuban family with typical, late-onset PD and probable autosomal dominant inheritance. Mean age at onset was 61.2 years (+/- 12.53, 45-76). Other phenotypes such as essential tremor and atypical parkinsonism were observed in this family. We carried out a genome-wide scan and linkage analyses. The genetic data were analyzed using a conservative model in which only patients with clinically definite or likely PD were considered affected, other phenotypes were regarded as "unknown." Multipoint analyses yielded a maximum LOD of 2.26 between markers D19S221 and D19S840. Haplotype analysis showed a region on chromosome 19 shared by six of seven PD patients. The essential tremor phenotype and the atypical parkinsonism do not segregate with this haplotype, suggesting a different etiology. Our findings suggest the presence of a novel locus for PD on chromosome 19p13.3-q12. We propose that an oligogenic model with moderate contribution of two or three genes rather than a "pure" monogenic model might explain better the wide range in age at onset, the reduced penetrance and the phenotypical variability observed in PD families.