Thanks again, folks.Pat, my ex-brother in law has been ill for some time, having had several deep vein thrombosis'(damn, what IS the plural for that?).He has significant pulmonary damage and, as I understand it, whilst still comparatively young at 36, is unlikely to be able to withstand any further problems.His life expectancy is therefore, not looking too good.It seems to have taken some considerable time for a diagnosis to be made and I guess that's why he has become so ill. As you say, I am lucky I know to have the kids tested and if necessary treated in time.