Biotinidase deficiency

If you and your partner are unaffected with biotinidase deficiency but you have had a child with biotinidase deficiency, it is likely that you and your partner are both carriers of a biotinidase deficiency-related BTD gene change. If both members of a couple are carriers of a biotinidase deficiency-related BTD gene change, then with every pregnancy between them there is a ¼ (25%) chance of the baby being affected with biotinidase deficiency, a ½ (50%) chance of the baby being a carrier of a single biotinidase deficiency-related gene change, and a ¼ (25%) chance of the baby being neither affected nor a carrier of biotinidase deficiency.

Genetic testing is available to confirm that both you and your partner are carriers of biotinidase deficiency, as would be expected once you have had an affected child. If you have questions about genetic testing options, or about your reproductive risks and options related to biotinidase deficiency, you can locate genetic counselors throughout the United States and Canada on the "Find A Genetic Counselor" searchable directory on the National Society of Genetic Counselors website.

If you are affected with biotinidase deficiency, then both copies of your BTD gene have a biotinidase deficiency-related gene change and all of your children will receive a biotinidase deficiency-related BTD gene change from you and at a minimum be carriers of biotinidase deficiency. Whether or not your children may be affected with biotinidase deficiency will depend upon the carrier status of your reproductive partner. If your partner is unaffected with biotinidase deficiency and also not a carrier, then all of your children will inherit a biotinidase deficiency-related BTD gene change from you and a working copy of the BTD gene from your partner and be unaffected carriers of biotinidase deficiency. If your partner is an unaffected carrier of biotinidase deficiency, then all of your children will inherit a biotinidase deficiency-related BTD gene change from you and will either inherit your partner's working copy of the BTD gene and be carriers of biotinidase deficiency or your partner's biotinidase deficiency-related BTD gene change and be affected with biotinidase deficiency (1/2 or 50% chance of either outcome with each pregnancy). If your partner is also affected with biotinidase deficiency, then all of your children will inherit a biotinidase deficiency-related gene change from each of you and all of your children would be expected to have biotinidase deficiency.

It is possible for an individual who wants to know their carrier status for biotinidase deficiency to have genetic testing. If you have questions about genetic testing options, or about your reproductive risks and options related to biotinidase deficiency, you can locate genetic counselors throughout the United States and Canada on the "Find A Genetic Counselor" searchable directory on the National Society of Genetic Counselors website.

If you do not have a family member with biotinidase deficiency or any reason to suspect that you might be affected with biotinidase deficiency, then the general population based chances that an individual is a carrier of biotinidase deficiency is estimated to be approximately 1 in 120 (0.8%).

If you do not have a family member with biotinidase deficiency or any reason to suspect that you might be affected with biotinidase deficiency, then the general population based chances that an individual is a carrier of biotinidase deficiency is estimated to be approximately 1 in 120 (0.8%). If both members of a couple each have an approximately 1 in 120 chance to be a carrier of biotinidase deficiency, then they would have an approximately 1 in 57,600 chance of having a child affected with biotinidase deficiency (1/120 x 1/120 x ¼).

If you do not have a family history of individuals known to be affected with or carriers of biotinidase deficiency, then your chances of being a carrier of biotinidase deficiency (general population rate) is approximately 1 in 120. While technically possible to do, carrier screening specifically for biotinidase deficiency is not generally offered/recommended during pregnancy. However, it is becoming increasingly common for individuals to be offered the option of carrier screening for a wide variety of genetic conditions prior to or during pregnancy (referred to as Universal Carrier Screening), and some biotinidase deficiency-related gene changes may be included on Universal Carrier Screening panels.

Genetic counselors can help you understand your reproductive risks and options, including preconception or prenatal carrier screening and genetic testing options. To locate genetic counseling services, you can use the searchable "Find A Genetic Counselor" directory on the National Society of Genetic Counselors website to locate genetic counselors throughout the United States and Canada.

If both members of a couple are known to be carriers of biotinidase deficiency and their specific biotinidase deficiency-related BTD gene changes are known, prenatal testing through chorionic villus sampling (CVS) or amniocentesis is an option to test for the presence or absence of biotinidase deficiency-related BTD gene changes in a baby before birth. It is also possible to measure biotinidase enzyme activity in cells obtained by amniocentesis, but molecular testing (looking for the specific BTD gene changes) is the preferred method for prenatal testing.

There may be differences of opinion amongst medical professionals and between individuals about whether genetic testing for biotinidase deficiency before birth, while technically possible, is warranted or not. Genetic counselors can provide valuable information and support during decision making for individuals considering reproductive testing options. To locate genetic counseling services, you can use the searchable "Find A Genetic Counselor" directory on the National Society of Genetic Counselors website to locate genetic counselors throughout the United States and Canada.

If both members of a couple are known to be carriers of biotinidase deficiency and their specific biotinidase deficiency-related BTD gene changes are known, in vitro fertilization (IVF) with preimplantation genetic diagnosis (PGD) for biotinidase deficiency is possible. This would enable identifying embryos not affected with biotinidase deficiency prior to implantation and only transferring embryos for possible pregnancy which are unaffected. It is recommended that prenatal testing through chorionic villus sampling (CVS) or amniocentesis be done to confirm the preimplantation genetic test results in pregnancies conceived through IVF with PGD.

There may be differences of opinion amongst medical professionals and between individuals about whether IVF with PGD for biotinidase deficiency, while technically possible, is warranted or not. Genetic counselors can provide valuable information and support during decision making for individuals considering reproductive options. To locate genetic counseling services, you can use the searchable "Find A Genetic Counselor" directory on the National Society of Genetic Counselors website to locate genetic counselors throughout the United States and Canada.