Smith-Magenis syndrome and tetralogy of Fallot

[...]a clinically recognisable phenotype has been described, 2-8 including brachycephaly, midfacial hypoplasia, a broad, flat nasal bridge, prominent lower jaw, inverted V shaped upper lip with a prominent cupid's bow, hoarse voice, speech delay, psychomotor and growth retardation, and behavioural problems which are often characteristic. The estimated frequency of cardiac lesions is 37% 4 and those which have previously been described include atrial septal defects, ventricular septal defects, tricuspid and mitral valve stenoses or regurgitation, mitral valve prolapse, subvalvular aortic stenosis, and supravalvular pulmonary stenosis. 2 4 The estimated frequency of SMS is 1 in 25000 but this may be an underestimate, as if the deletion is small it may be missed on routine cytogenetic analysis and may only be detectable by fluorescence in situ hybridisation (FISH).