Williams-Beuren syndrome associated with caudal regression syndrome and coagulopathy--a case report.

Williams-Beuren syndrome is a genetic disorder caused by a heterozygous deletion at 7q11.23. The present report describes a female patient with Williams-Beuren syndrome combined with caudal regression syndrome and two forms of coagulopathy. Besides the typical developmental abnormalities such as mental and growth retardation, a distinctive facial appearance, and cardiovascular anomalies, our patient showed fusion of fourth and fifth lumbar vertebra and a sacrococcygeal agenesis. Blood coagulation tests revealed a deficiency of coagulation factor XI and XII. Magnetic resonance imaging angiography showed multiple vascular stenoses mainly in the abdominal aorta and its major branches as a consequence of the insufficient elastin gene. Previous reports identified a deletion of HLXB9 as a possible genetic cause of the caudal regression syndrome, which could not be identified in the present case. This unusual combination of the above-mentioned genetic disorders has not been published so far.