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Carriers of Hemophilia or prenatal diagnosis. Women may choose these options What if I would like additional information? for a number of different reasons. To discuss these options, contact your local hemophilia treatment center’s genetic If you have any questions regarding this information, would counselor. like additional information, or to pursue testing, you can contact your local hemophilia treatment center. They can Pre-implantation Genetic Diagnosis (PGD) put you in touch with a genetic counselor at the hemophilia » PGD is used to diagnose hemophilia prior to the embryo center or in your area. You can find a hemophilia treatment Carriers being implanted in the uterus. It involves in vitro center near you at http://www.cdc.gov/ncbddd/hemophilia/ fertilization of embryos, followed by genetic testing HTC.html. You can also find a genetic counselor in your area of the fertilized embryos to determine which have by visiting the National Society of Genetic Counselors website hemophilia and which do not at www.nsgc.org. of » The embryos that are not affected by hemophilia will be implanted » The hemophilia mutation must be known in the family Where can I find more information? prior to performing PGD Please visit the following websites: Hemophilia Canadian Hemophilia Society Chorionic Villus Sampling (CVS) » http://www.hemophilia.ca/en/bleeding-disorders/ » CVS is performed during the first trimester, typically 10- carriers-of-hemophilia-a-and-b/ 13 weeks into the pregnancy » CVS uses an ultrasound and catheter to obtain a sample Centers for Disease Control of the tissue on the edge of the placenta (chorionic villi) Hemophilia Information for Women What you need » http://www.cdc.gov/ncbddd/hemophilia/women.html » This tissue can then be tested for the family’s disease- causing mutation National Hemophilia Foundation » This is an invasive test; there is an approximate 0.5% www.hemophilia .org to know (1/200) to 1% (1/100) chance for miscarriage associated » http://www.hemaware.org/story/test-takers with the procedure » http://www.hemaware.org/story/family-planning-carriers » http://www.hemaware.org/story/knowledge-power- Amniocentesis symptomatic-carriers » Amniocentesis is a procedure performed after 15 weeks into the pregnancy World Federation of Hemophilia » It is performed using ultrasound and a long, thin needle » http://www.wfh.org/ to obtain a sample of the amniotic fluid surrounding the baby. Within this fluid are cells from the fetus which can be tested for the family’s disease-causing mutation » Amniocentesis is also an invasive procedure and, therefore, is associated with an approximate 1/300 Indiana (0.3%) chance for miscarriage Hemophilia & Thrombosis Center 8326 Naab Road, Indianapolis, IN 46260 Tel: 317-871-0000 | Toll Free: 1-877-256-8837 | Fax: 317-871-0010 www.ihtc.org | http://www.facebook.com/IndianaHemophilia ©2017 Indiana Hemophilia & Thrombosis Center , Inc. Rev 8/17 What is hemophilia? Inheritance of Hemophilia Can a factor level tell me if I’m a carrier? identified, carrier testing is available to at-risk female Father With Hemophilia & Mother Who is Not a Carrier relatives by means of a DNA blood test. This is performed Hemophilia is an inherited bleeding disorder. People with Parents In the past, prior to the availability of genetic testing, factor by looking for the presence or absence of the same hemophilia often bleed longer than other people. Bleeding levels were used to determine carrier status. This method mutation can occur internally into joints and muscles, or externally, of determining carrier status is not reliable. For this reason, » If no male relative with hemophilia is available for from cuts, dental procedures, or trauma. The two most factor levels in female hemophilia carriers should be + testing, DNA blood testing can still be performed; common forms of hemophilia are hemophilia A, a deficiency used only to determine the risk for experiencing bleeding however, it may not be able to detect all mutations of clotting factor VIII, and hemophilia B, a deficiency of Father Mother symptoms, not to determine carrier status. with not a carrier for clotting factor IX. hemophilia hemophilia XY XX Where does hemophilia come from? Limitations of Carrier Testing The genes for both factor VIII and factor IX are located on the » Deletions (missing genetic information) or duplications Hemophilia can occur in families both with and without X chromosome (one of the two sex chromosomes in humans). (extra genetic information) in the factor VIII and IX genes a history of hemophilia. The majority of babies with Abnormalities (mutations) in the factor VIII gene cause are more difficult to detect in females if the mutation in hemophilia are born to women who are carriers. In hemophilia A, while mutations in the factor IX gene cause Son Daughter Son Daughter the family is not known without carrier for without carrier for some cases, these women do not have a family history hemophilia B. Hemophilia varies in severity, depending upon hemophilia hemophilia hemophilia hemophilia » of hemophilia and do not know that they are hemophilia When carrier testing is performed with no previous the level of clotting factor circulating in the blood. Males with XY XX XY XX detection of the factor VIII or IX gene mutation, a normal Children carriers until their child is diagnosed. severe hemophilia typically have less than 1% of normal factor result in an at-risk individual does not rule out that she is activity, those with moderate have 1-5%, and those with mild more often than females because females have an additional Possible Carriers: a carrier hemophilia have 6-40%. Males with severe hemophilia are X chromosome that acts as a “back-up.” Because males only » A woman whose son is the first person in his family to be typically diagnosed before their first birthday while those have one X chromosome, any mutation in the factor VIII or affected with hemophilia has an 80% chance of being a Why is it important to know if I’m a carrier? with moderate/mild hemophilia may not be diagnosed until IX gene will result in hemophilia. Females with a mutation on carrier. The only way to determine if she is a carrier is by childhood or adolescence. There are also some individuals one X chromosome are called “carriers”. performing genetic carrier testing » Hemophilia carriers may be at risk for bleeding symptoms with mild hemophilia who are not diagnosed until adulthood. » Carrier’s sons can have hemophilia and daughters can be Currently there is no cure for hemophilia, but treatment is A female carrier has a 50% chance of passing on the gene » A woman whose mother is a hemophilia carrier has a carriers with a chance for bleeding symptoms available. causing hemophilia to each of her children. Each son has a 50% chance of being a carrier. The only way to determine 50% chance of having hemophilia and each daughter has a if she is a carrier is by performing genetic carrier testing » If desired, a carrier can learn if her fetus is affected with X-linked inheritance 50% chance of being a carrier like her mother. A man with » The chance for other female relatives of an individual hemophilia before birth Humans are born with 46 chromosomes, half from their hemophilia will pass the gene on to none (0%) of his sons and with hemophilia are based upon the specific family » It is important to be aware of the recommendations for mother and half from their father. Females have two “X” all (100%) of his daughters. Therefore, his sons will not inherit relationships and may be determined by a genetic pregnancy and delivery chromosomes (XX) and males have a single “X” and a single hemophilia, but all of his daughters will be carriers. counselor “Y” chromosome (XY). X-linked disorders are associated with mutations on the X-chromosome. These disorders affect males Do carriers of hemophilia have symptoms? Obstetric Recommendations Obligate Carriers: » To prevent bleeding in a newborn, there are specific Inheritance of Hemophilia » About 30% of female carriers are at risk for bleeding » A woman is called an obligate carrier if it is known that recommendations for delivery of a male infant who has “Carrier” Mother & Father Without Hemophilia problems due to having a low factor level. These women she is a carrier of hemophilia based upon her family a chance of having hemophilia. This includes not using Parents usually exhibit mild symptoms of hemophilia and may history vacuum extraction or forceps to deliver the baby. It is need treatment to prevent bleeding complications or » A woman who has more than one affected son is an important to identify if a woman is a carrier to know minimize symptoms obligate carrier what precautions, if any, should be taken at delivery + » Hemophilia carriers more commonly have heavy » A woman who has an affected son and one or more » In addition, for families with severe and moderate menstrual periods, bruising, and nosebleeds. They may hemophilia, it is recommended that circumcision be Father Mother affected relatives in her family line (a brother or uncle, without carrier for delayed until it is determined if the baby has hemophilia. hemophilia hemophilia also bleed more during surgery, after an injury, or after for example) is an obligate carrier. XY XX delivering a baby This testing can be performed by measuring the factor » All daughters of men with hemophilia are obligate VIII or IX level from a sample of the umbilical cord blood » It is important to know that factor VIII levels can change in carriers pregnancy, with oral contraceptive use, aerobic exercise, obtained at delivery and chronic inflammation How do I know if I’m a carrier? Son Daughter Son Daughter Reproductive Options without carrier for with does not carry hemophilia hemophilia hemophilia hemophilia gene Carrier Testing Women who have a chance to have a baby with hemophilia XY XX XY XX » It is best to start genetic testing in a male in the family have multiple reproductive options, including natural Children with hemophilia to identify the mutation in the factor conception, egg donation, or adoption.
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