RING CHROMOSOME-18 IN A NEWBORN

A female newborn with ring chromosome 18 presented with the following clinical features: antimongoloid position of the eyelid, pseudentropiu m of the lower lid, low-set ears, midface dysplasia, down-turned mouth , micrognathia, webbing of the neck, short stature, widely separated n ipples, simian crease, microacrodactyly. In addition, atrial and ventr icular septal defect, absent corpus callosum, cerebral convulsions, an abnormal EEG pattern, and laboratory findings consistent with a trans ient neonatal hyperthyreotropinemia were detected. Cytogenetic investi gations revealed a 46,XX,r(18) (p11.32q21.3) karyotype. Due to the var iable deletion at both long and short arm of chromosome 18, the clinic al presentation of patients with ring chromosome 18 shows a considerab le degree of variation. Consequently, common signs like mental retarda tion, developmental delay, impaired hearing and speech, and midfacial dysplasia are not mandatory, as had been stated previously. Apart from audiometry and the evaluation of serological IgA-levels the patient's thyroid function ought to be assessed. Transmission of a ring chromos ome 18 from parents to their children has been reported in several cas es.