We report on a family with three children, 2 of which had typical clinical findings of PWS: mental retardation, hypogonadism, hypotonia, hyperphagia, obesity and also strabismus and synophridia; during pregnancy reduced fetal movement was noted. The Fish probes (SNRPN and D15S10), Methylation specific PCR (MPCR), Southern blot and microsatellite markers confirmed in the PWS brothers a large deletion at least of the area comprising between D15S63 and GABRA5.