The syndrome of trisomy 10q24leads to 10qter is described from three patients studied by the authors and five cases reported from the literature. The characteristic dysmorphy of the syndrome, although different from that of trisomy 21, nevertheless is reminiscent because of euroasiatic facies. The facies is broad, round, because of euroasiatic facies. The facies is broad, round, and flat, with a prominent malar region and a high and convex forehead. Palpebral fissures are narrow with bilateral epicanthal folds, and the nasal bridge is hypoplasitc. Marked joint laxity allows spontaneous and reductible subluxations. Growth retardation is the rule, and mental retardation is severe. No specific dermatoglyphic abnormalities are noted; there is a gap between the first and second toes, with a marked plantar crease separating them. Although trisomy 10q24leads to10qter results from various terminal translocations or pericentric inversion in one case, the location of the breakage point in band 10q24 suggests a particular lability of this zone.