Lymphatic vessel hypoplasia in fetuses with Turner syndrome

Turner syndrome is associated with subcutaneous accumulation of fluid in th e neck region that can be visualized sonographically from 10-14 weeks of ge station as massively increased nuchal translucency thickness. Possible mech anisms for this increased translucency include dilatation of the jugular ly mphatic sacs because of developmental delay in the connection with the veno us system, or a primary abnormal dilatation or proliferation of the lymphat ic channels interfering with a normal flow between the lymphatic and venous systems. The aim of this study was to investigate the distribution of lymp hatic vessels in nuchal skin tissue from fetuses with Turner syndrome compa red with fetuses carrying trisomies 21, 18 and 13 and chromosomally normal controls. The distribution of vessels was examined by immunohistochemistry using a monoclonal antibody, PTN63, against 5'nucleotidase and an anti-lami nin antibody. In normal control fetuses (n = 6) and those with trisomies 21 (n = 3), 18 (n = 2) and 13 (n = 2), PTN63-positive and laminin-positive ve ssels were evenly distributed throughout the dermis and subcutis, In Turner syndrome (n = 3), there was a chain of large vessels that stained with bot h PTN63 and laminin at the border between dermis and subcutis, but there wa s scarcity of vessels in the upper dermis and the subcutis, Using PTN63 alo ne, there were no positive vessels in the upper dermis, We conclude that in Turner syndrome lymphatic vessels in the upper dermis are hypoplastic.