[Ring chromosome 8: microcephaly, mental retardation and minor facial anomalies with adhesive behavioral phenotype]. / Cromosoma 8 en anillo: microcefalia, retardo mental y disformias leves con fenotipo conductual adhesivo.

INTRODUCTION: Since the first description of ring chromosome 8 [r(8)] in 1973, only a few patients have been reported. In this report we present a child with this anomaly, and we compare his clinical manifestations with previously reported patients. CLINICAL CASE: A 12 year-old boy presented with low birth weight, mental retardation, microcephaly, short stature, hypotonia, and minor facial anomalies: hypotelorism, bilateral epicanthic folds, long philtrum, thin lips, narrow palate, micrognathia and low-set ears. Digital anomalies were bilateral brachyclinodactily of the fifth finger, and cutaneous syndactyly between second and third fingers. The boy had a pleasant personality but exhibit attachment for people and things with unrestricted affect. Cytogenetic analysis on peripheral white blood cells showed a r(8) chromosome. Parental karyotypes were both normal. CONCLUSIONS: The major features in the boy studied by us were found also in the other cases reported with an r(8) chromosome, but all they were non-specific features, and do not support the existence of a readily recognizable r(8) chromosome syndrome . Follow-up data with special emphasis on the behavioral characteristics are needed for defining an specific behavioral phenotype.