Gene Linked to Lymphatic Abnormalities

Genetic analysis and a new lymphatic imaging technique, has shown that the lymphatics are involved in a rare vascular disorder.

When the lymphatics are not functioning, malnutrition, infection and severe edema can ultimately result, which further complicates the diagnosis and treatment of vascular disorders.

Scientists at the University of Texas Health Science Center (Houston, TX, USA) imaged the lymphatics in a patient with a suspected RAS (rat sarcoma) p21 protein activator 1 (RASA1) gene mutation that is known to be linked to Parkes-Weber syndrome (PKWS). This syndrome presents with capillary malformations and arteriovenous fistulas that are associated with abnormal bleeding and heart failure. Imaging techniques included near-infrared fluorescence lymphatic imaging (NIRFLI) developed using military grade night-vision goggle technology.

The investigators used state-of-the-art whole exome sequencing techniques and bioinformatics techniques, and then singled out RASA1 as the only potential causative gene of the disorder in the human research subject. They confirmed the human subject findings in a mouse model developed at the University of Michigan (Ann Arbor, MI, USA). The mouse model not only had a similar RASA1 mutation to the human subject, but a similarly abnormal lymphatic system as imaged by NIRFLI. The team's genetic discovery could be used to identify future pharmacologic strategies to alleviate more common-lymphatic disorders

Eva Sevick-Muraca, PhD, the senior author of the study said, “This study is a game changer. This is a rare case in which we were able to image lymphatic abnormalities in both a patient and a mouse model that harbored similar mutations known only to be associated with vascular malformations. The striking results underscore the potential role of the lymphatics in vascular disorders." The study was published on May 21, 2013, in the journal Proceedings of the National Academy of Sciences of the Unites States of America (PNAS).

Related Links:
University of Texas Health Science Center
University of Michigan