The term variants is now used in place of the term mutation. Genes are contained on chromosomes. Chromosomes, and the genes on those chromosomes, are passed on from parent to child. Errors in the DNA that make up a gene are called variants and can lead to diseases. They are called carriers A person who has one copy of a gene mutation for a particular autosomal recessive disorder remember genes come in pairs. Carriers are not affected by the disorder.
However, they can pass on the gene variant to their children. Children who inherit two such gene variants will be affected by the disorder. Genetic Relating to or due to genes and heredity or the field of studying genes and heredity. Genetic counselors can answer your questions about how VLCADD is inherited, options during future pregnancies, and how to test other family members.
Ask your doctor about a referral to a genetic counselor These are health care providers who have special training in genetic conditions.
They help families understand genetic disorders and how they are passed down. Genetic counselors offer information and support to people who have genetic conditions in their families or are concerned that they may have a child with an inherited disorder. The sequence of the bases spell out instructions for making all of the proteins needed by an organism.
A gene is a section of DNA that holds the instructions for a specific protein. A change in one or more of the DNA bases making up a gene is called a mutation.
Some mutations change the protein instructions and can lead to particular health problems or disorders. Each parent passes half of their chromosomes, and thus half of their DNA instructions, onto their children. It is these instructions that cause certain traits, such as eye or hair color, to be inherited. It can also be helpful for carrier testing or prenatal diagnosis, discussed below. The sample needed for this test is obtained by either CVS or amniocentesis This is a test done during pregnancy.
A needle is used to remove a small sample of fluid from the sac around the fetus. The sample can be used to test for certain genetic disorders in the fetus. Amniocentesis to test for genetic conditions is usually done between 13 and 20 weeks of pregnancy. Parents may either choose to have testing during pregnancy or wait until birth to have the baby tested.
Parents may also choose to use assisted reproductive techniques to decrease the chance that their future children would have VLCADD. A genetic counselor can talk to you about your choices and answer other questions you may have about prenatal testing or testing your baby after birth.
Finding out whether other children in the family have VLCADD is important because early treatment may prevent serious health problems. Except in special cases, carrier testing should only be done in people over 18 years of age. It is important for other family members to be told that they could be carriers. However, when both parents are carriers, newborn screening The process of testing for disease in a person who does not show signs of having the disease nonsymptomatic or asymptomatic person.
The goal of screening is to catch the disease in its early stages. In this case, special diagnostic testing should be done in addition to newborn screening. A small number of women are known to have developed:. All women with a family history of VLCADD should share this information with their obstetricians and other health care providers before and during any future pregnancies.
Knowing about these risks allows early treatment. Carrier testing Carrier testing may be available to other family members. Your metabolic doctor or genetic counselor can advise you about carrier testing.
Your baby will need to be on a restricted diet to avoid fats that he or she cannot break down. A dietician or nutritionist can help you plan a low-fat diet that still gives your baby the nutrients he or she needs for healthy growth and development. Your baby will also need to eat often in order to avoid many of the signs mentioned in the Early Signs section. Taking prescription L-carnitine supplements can help break down fats for energy and remove harmful substances in the body.
Treatments need to continue throughout life. When we eat food, enzymes help break it down. Certain enzymes help break down fats into their building blocks, fatty acids. Other enzymes break down these fatty acids for energy. Fatty acids are built like chains, and they come in many different lengths.
They are classified as either short, medium, long, or very long. Different enzymes work on different lengths of fatty acids. This is harmful because your baby needs fat for energy when there are not enough sugars to break down for energy, such as between meals. VLCAD is an autosomal recessive genetic condition. This means that a child must inherit two copies of the non-working gene for VLCAD, one from each parent, in order to have the condition. Early-onset cardiomyopathy, a disease that makes it harder to pump blood, is common in infants with VLCAD deficiency and leads to high mortality rates.
Those who make it through infancy to later childhood can still experience the same life-threatening problems they did in infancy, but the frequency of these issues typically begins to decrease with time.
Part of the reason for this change is that as children age, they are able to go longer periods of time in between eating without the threat of hypoglycemia. Genet Med. Epub Apr 2. Mol Genet Metab. Epub May Neuromuscul Disord. Epub Mar Epub Sep 2. J Pediatr. Citation on PubMed.
0コメント