Editor—Williams syndrome (WS) is generally characterised by mental deficiency, gregarious personality, dysmorphic facies, supravalvular aortic stenosis (SVAS), and idiopathic infantile hypercalcaemia. Patients with WS show allelic loss ofSTX1A,1 elastin (ELN),2 3 andLIMK1,4 with most exhibiting a submicroscopic deletion at 7q11.23, detectable by FISH.3 5 The common deletion size is about 1.5 Mb.6 Previous studies have shown that WS patients have consistent deletion sizes and share common proximal and distal breakpoints.7 8 Here we report a patient who has a large, atypical, visible chromosomal deletion of 7q11.2 and features consistent with, and in addition to, those typically seen in Williams syndrome.

The patient was originally referred to the genetics clinic at 5 months of age for evaluation of global developmental delay and dysmorphic features. She was delivered at 37 weeks' gestation by caesarean section weighing 2350g (<5th centile). The initial course included a history of poor feeding in the newborn period. Clinical examination showed macrocephaly, cutaneous haemangioma, and craniofacial features consisting of a large anterior fontanelle, frontal bossing, depressed nasal bridge, cup shaped ears, hypertelorism, and prominent lips (fig1A). Neurological examination showed generalised hypotonia with heel cord and hamstring tightness. CT scan of the head and renal ultrasound were normal. Because of a grade III/VI systolic murmur, echocardiogram was performed, which showed a slightly thickened aortic valve. Cytogenetic analysis showed a 46,XX karyotype.

Re-evaluation at 4 years of age, showed short stature (90 …