Genetic Disorders of the Lymphatic System

Abstract Lymphedema is the swelling of any body part caused by a fault or malformation (primary) or obstruction (secondary) in the lymphatic system. Primary lymphedema is highly heterogenous, and several causative genes have been identified in the recent past. The swelling may present at birth (congenital), but some genetic forms may not present till later in life, especially in the pubertal period (late onset). The lymphatic problems may be more widespread causing intestinal lymphangiectasia, chylothoraces or pericardial effusions, or may even present in utero with nonimmune fetal hydrops. Lymphedema is also a complication of a number of syndromes, many of which are associated with intellectual disability. This chapter will focus on the genetics and clinical presentation of different forms of primary lymphedema and provides a model for the diagnosis and classification of primary lymphedema.