Phenotypic variability in the syndrome of ring chromosome 21 - R(21) - Kamiya, Tânia Yoshico; Guion-Almeida, Maria Leine; Zechi-Ceide, Roseli Maria; Pittoli, Siulan Vendramini Paulovich; Rodini, Elaine Sbroggio de Oliveira (Simpósio Internacional de Fissuras Orofaciais e Anomalias Relacionadas, 2009)