[Ring chromosome 8: microcephaly, mental retardation and minor facial anomalies with adhesive behavioral phenotype]

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.

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.

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.