[Ring chromosome 21 syndrome: report of 2 cases].

Background: When a chromosome undergoes 2 distal breaks and the broken ends join together, they form a ring chromosome. Ring 21 syndrome is described with a phenotype with minor dysmorphisms, thrombocytopenia, psychomotor and language delay. The objective of this work is to display 2 cases of male patients with ring chromosome 21.

Clinical cases: The first case was a 5-year-old male patient, with psychomotor and language delay. Broad forehead with prominent metopic suture, bilateral epicanthic fold, hypotelorism, left esotropia, low-set asymmetrical pinnae, micrognathia, lower extremities with deep plantar folds. Karyotype 46,XY,r(21)(p11.2q21)[25]. The second case was an 8-year-old male patient with psychomotor and language delay. Skull with flattened occiput, triangular facies, midfacial flattening, palpebral fissures directed downwards, bilateral epicanthic fold, low-set and asymmetrical pinnae, micrognathia, prominent asymmetrical thorax on the right side, hands with irregular palmar folds. Karyotype: 46,XY,r(21)(p11q22)[25].

Conclusion: Craniofacial dysmorphisms with psychomotor and language delay were the most relevant clinical data in both cases.