1Ll Al-Gazali, 2J. Hertecant, 3R. Ahmed, 4R. Padmanabhan
1UAE University Faculty of Medicine and Health Sciences, Paedatrics, PO Box 17666, Al Ain, UAE, 2Tawam Hospital, Paediatrics Dept., P.O. Box 15258, Al Ain, UAE, 3Al Ain Hospital, P.O. Box 1006, Al Ain, UAE, 4UAE University Faculty of Medicine and Health Sciences, Anatomy, PO Box 17666, Al Ain, UAE
Hennekam syndrome is an autosomal disorder characterized by midfacial hypoplasia, intestinal lymphangiectasia, peripheral lymphedema, seizures, growth retardation and variable degree of mental retardation (Hennekam et al., 1989 Am J Med Genet 34:593-600.). So far 24 cases have been reported in the literature. Van Balkom et a., 2002 Am J Med Genet 112:412-21) recently emphasized variability of the phenotypes of the syndrome and suggested the possible existence of phenocopies and genocopies. Here we report 4 children from four inbred Arab families with variable manifestation of Hennekam syndrome with additional features that were not previously reported. These include abnormalities of the middle ear, anomalous pulmonary venous drainage, interrupted inferior vena cava, polysplenia, crossed renal ectopia, median position of the liver and multiple cavernous haemangioma. That the lymphatics largely develop as outsproutings from the veins has been widely accepted now. Since anomalies of the veins and the consequent developmental abnormalities of the lymphatics might lead to alterations in the fluid balance of the embryos, we hypothesize that altered fluid dynamics due to defective vascular and lymphatic development may disrupt critical events in craniofacial morphogenesis, such as neural crest cell migration, and growth and differentiation of the facial primordia of neural crest origin resulting in Hennekam syndrome.
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