AN 11-month-old girl, severely retarded both physically and mentally, has a karyotype exhibiting 46 chromosomes normally paired except for the 4-5 group. In this group one normal pair of chromosomes is identifiable. The other pair comprises one chromosome of normal length and an outsized partner as long as the chromosomes of pair 1.
Report of a Case
This patient was being treated by one of us (E. W.) for a chronic urinary infection. Nine months old at the time, she did not smile, did not grasp objects, and did not vocalize. She was unable to turn from the supine position to the prone and could not sit up. Her height was 24 inches (61 cm) and her weight, 13 lb 9 oz (6,152 gm). Her head was long and narrow, measuring 16⅞ inches in circumference. Her palate was high and arched. Epicanthal folds were present. She had short, stubby hands