A case of malignant spinal cord ependymoma in association with a duplication of part of the long arm of chromosome 12

Abstract

A 12 year old girl of Greek Cypriot origin presented with progressive gait disorder. There was no relevant family history. Her early development was rather slow and she made poor progress at a normal school. An assessment using the WISC had given her a full scale IQ of 65. On admission she was found to be microcephalic with a head circumference of 47.5 cm, which is more then -3 SD below the mean. There were some dysmorphic features: arachnodactyly, hypermobile joints, proximally placed thumbs, and immobile first metacarpal-phalangeal joints. Forced eye closure produced an appearance reminiscent of a whistling face. There was marked weakness of the legs, in the left more than the right, with pathologically brisk tendon reflexes and bilateral extensor plantar responses, but she was still able to walk. In the upper limbs there was a mild degree of pyrimidal weakness, on the left more than the right, and an intention tremor. Sensory testing was difficult because of her poor cooperation. A myelogram showed a large intramedullarly tumour in the upper thoracic and cervical region. The CSF protein was markedly raised. During the patient's first admission cytogenetic studies on peripheral blood cultures were carried out. Giemsa banded chromosome preparations showed an abnormality of chromosome 12, which was interpreted as a possible duplication of band q15, together with parts of the two adjacent bands (q14.3 and q21.1), in which case her chromosome complement would be written: 46,XX,dup(12)(q14.3→q21.1). However, more than one interpretation is possible and instead of a duplication, the abnormality could be the result of an interstitial insertion of chromosome material of unknown origin.