My granddaughter had familial hemophagocytic lymphohistiocytosis when she was 8 months old. Can her brothers also develop this disease? I have noticed that both of the boys have had skin problems but the older one, now 13, has developed asthma and unexplained headaches. My granddaughter received a BMT from the 2nd born who is now 11 years old. Is there any testing we can have done to check the boys for the presence or absence of the disease?