Two unrelated patients, aged 19 and 6 years, were studied and diagnosed as having Myhre syndrome (MS). This review, together with three previous cases, permits further delineation of MS. The main features are: short stature, mental retardation, blepharophimosis, muscular hypertrophy, decreased joint mobility, thick calvarium, broad ribs, hypoplastic iliac wings and short tubular bones. Advanced paternal age at the propositi's birth suggests an autosomal dominant mutation as the cause of MS.