Because the disease-causing gene is located on the X chromosome, a female born with an MECP2 mutation on her X chromosome has another X chromosome with an ostensibly normal copy of the same gene, while a male with the mutation on his X chromosome has no other X chromosome, only a Y chromosome; thus, he has no normal gene. Without a normal gene to provide normal proteins in addition to the abnormal proteins caused by a MECP2 mutation, the XY karyotype male fetus is unable to slow the development of the disease, hence the failure of many male fetuses with a MECP2 mutation to survive to term. Females with a MECP2 mutation, however, have a non-mutant chromosome that provides them enough normal protein to survive longer. Research shows that males with Rett syndrome may result from Klinefelters syndrome, in which the male has an XXY karyotype. Thus, a non-mutant MECP2 gene is necessary for a Retts-affected embryo to survive in most cases, and the embryo, male or female, must have another X chromosome. There have, however, been several cases of 46,XY karyotype males with a MECP2 mutation (associated with classical Rett syndrome in females) carried to term, who were affected by neonatal encephalopathy and died before 2 years of age.
Hepatic artery thrombosis occurs when a blood clot forms in the artery that provides blood flow to the liver. Hepatic artery thrombosis may occur as a complication after liver transplantation, and represents the most common complication of liver transplantation. Smoking tobacco increases the risk of hepatic artery thrombosis in people who have undergone liver transplantation.Hepatic artery thrombosis may cause severe elevations in serum aminotransferases, alanine transaminase (ALT) and aspartate transaminase (AST). Often the AST is greater than the ALT. Hepatic artery thrombosis is usually diagnosed with ultrasound with doppler, although it may be diagnosed using computed tomography (CT) or magnetic resonance imaging (MRI). The treatment for recently developed or acute hepatic artery thrombosis include anticoagulant medications, fibrinolytic therapy to break up the blood clot, or surgical revascularization. If acute hepatic artery thrombosis occurs after liver transplantation, then retransplantation with a new liver may be necessary. Signs and symptoms
Hepatic artery thrombosis can cause severe elevations in serum liver enzymes, AST and ALT. Often the AST is greater than the ALT. When it occurs after liver transplantation, it usually develops within 4 months after surgery. Diagnosis
Hepatic artery thrombosis is diagnosed with ultrasound with doppler, which shows a lack of blood flow through the hepatic artery. Hepatic artery thrombosis may also be diagnosed using CT or MR imaging, which would show evidence of a blood clot within the hepatic artery. Treatment
Treatment for acute hepatic artery thrombosis include anticoagulant medications, fibrinolysis therapies to break up the blood clot, or surgical revascularization.