ABSTRACT
<p><b>INTRODUCTION</b>Williams syndrome (WS) is a rare but well recognised neurodevelopmental disease affecting the connective tissue and the central nervous system. Many patients are identified through the presence of dysmorphic features and associated cardiac abnormalities. Klinefelter syndrome (KS) is associated with gynaecomastia, small testes, azoospermia and elevated gonadotropin levels. They are recognised in the second decade of life by their tall stature and delay in pubertal development. A combination of constitutive WS and KS has yet to be described.</p><p><b>CLINICAL PICTURE</b>We report a child with these genetic aberrations, highlighting the clinical characteristics of such an individual.</p><p><b>CONCLUSION</b>The manifestations and interactions of both conditions are also discussed.</p>