Editor—Application of chromosome painting has enabled confirmation that an additional segment in a presumed tandem duplication originates from the rearranged chromosome. More recent studies to determine more accurately the exact amount of duplication with cosmid FISH probes have, in a few instances, shown that some of the presumed duplications were in fact triplications of smaller segments.1-7 In some of these patients, unequal distances between the FISH signals showed that the middle segment of the tandemly arrayed three segments was in the opposite orientation to the two flanking segments,1 3 4 thus providing clues to the possible mechanism of formation.

Here we report on the clinical, cytogenetic, and molecular analysis of a patient displaying the same type of triplication for segment 13q14 including the retinoblastoma gene, again with opposite orientation of the middle segment.

The proband was born at term after an uneventful pregnancy to healthy, consanguineous, Turkish parents (third cousins). At the birth, the mother was 23 and the father was 28 years old. The patient's birth weight was 2700 g (<10th centile). At the age of 4 years, she was referred to a paediatric hospital for evaluation of developmental delay. Her weight (8 kg), height (85.0 cm), and head circumference (43.5 cm) were all far below the 3rd centile. Her cognitive abilities were estimated to be at the level of a 2 year old (IQ of about 50). Clinical assessment showed the following findings (fig 1): low frontal hairline, prominent antihelices and hypoplastic lobules of the ears, upward slanting palpebral fissures, deep set eyes, a capillary haemangioma next to the right eyebrow, a bulbous nasal tip, thin upper lip, pointed chin, excessive dental caries, right transverse palmar crease, diminished flexion in the metacarpophalangeal joints of both thumbs, and hypertrichosis of the legs.