For diagnosing spinal muscular atrophy (SMA), certain tests are carried out to check if your child has this condition. Also, a few tests may be done to identify if you are at risk of having a child with the condition.
Tests before getting pregnant
Consult a physician if you are planning a pregnancy and
- You had a previous child with SMA.
- You have a history of the condition in your family.
- Your partner has a history of SMA in their family.
Your physician may ask you to undergo genetic counseling to understand the risk of your child having SMA.
Some of the options that the genetic counselor might suggest include
- Getting pregnant and waiting to see if your child is born with SMA.
- Using donated sperm or eggs to get pregnant.
- Pre-implantation genetic diagnosis (PGD) is done after a woman’s eggs are fertilized in the laboratory and the resultant embryos are tested for SMA before they are implanted in the uterus.
Tests during pregnancy
If during pregnancy, you are aware that there is a risk of your child having SMA, the physician might suggest the following tests
- Chorionic villus sampling (CVS): At 11 to 14 weeks of pregnancy, a sample of cells from the placenta is tested.
- Amniocentesis: At 15 to 20 weeks of pregnancy, a sample of amniotic fluid is tested.
If these tests show a positive result, talk to your physician about your future options. Please note that these tests can slightly increase the risk of miscarriage.
Tests after birth
If you or your child exhibit typical symptoms of spinal muscular atrophy (SMA), a genetic blood test can confirm the condition. In genetic testing, a blood test is carried out to check for the presence of the SMN1 gene (survival motor neuron 1 gene).
The physician may also perform the following tests to diagnose SMA
- Physical examination: To look for signs of SMA.
- Electromyography: This involves the insertion of thin needles into a muscle to detect its functioning.
- Muscle biopsy: The physician removes muscle cells through a needle or by making a small cut in your child’s skin.
- Imaging tests: Computed tomography (CT) scan or magnetic resonance imaging (MRI) helps to visualize the organs and structures inside the body.
- Creatinine kinase test: This test helps to distinguish if a person has SMA or another type of neuromuscular disease.
What is spinal muscular atrophy?
Spinal muscular atrophy (SMA) is a genetic condition that results in weakness and wasting of muscles in infants. It also causes atrophy, where the muscles get smaller.
In SMA, the nerve cells in the brain and spinal cord break down. As a result, the brain can’t send a signal to the muscles to make them move, leading to muscular atrophy. SMA can affect the child’s ability to
- Sit up
- Control head movements
Severe SMA can injure the muscles used for breathing and swallowing.
In most cases, SMA is caused by inadequate production of a protein called survival motor neuron (SMN) protein. Rarely, SMA is caused by mutations in other genes apart from SMN.
Health Solutions From Our Sponsors
Top How Do You Diagnose Spinal Muscular Atrophy Related Articles
AmniocentesisDuring an amniocentesis, a sample of the amniotic fluid is taken to screen for certain birth defects (Down's syndrome, neural tube defects, spina bifida, cystic fibrosis), lung maturity of the fetus, infection, or chromosome analysis. Amniocentesis is recommended for women giving birth after the age of 35.
Chorionic Villus SamplingThis prenatal test involves taking a small sample of cells from the placenta to check for birth defects, genetic diseases, and other problems. Candidates for the test include pregnant women age 35 years or older, couples who have had a child with a birth defect, and pregnant woman who have had other abnormal genetic test results. Potential risks of the test include miscarriage and infection. Cells may be collected through the vagina or through the abdomen.
Family Health History: Genetics, DNA Testing and Your HealthWebMD explains why your doctor asks about your relatives' health conditions and how you can get the information if you don’t know.
Genetic CounselingYour health care provider may refer you to a genetic professional. Universities and medical centers also often have affiliated genetic professionals, or can provide referrals to a genetic professional or genetics clinic. Genetic counseling provides patients and family members the tools to make the right choice in regard to test for a disease or condition.
Genetic Diseases (Disorder Definition, Types, and Examples)The definition of a genetic disease is a disorder or condition caused by abnormalities in a person's genome. Some types of genetic inheritance include single inheritance, including cystic fibrosis, sickle cell anemia, Marfan syndrome, and hemochromatosis. Other types of genetic diseases include multifactorial inheritance. Still other types of genetic diseases include chromosome abnormalities (for example, Turner syndrome, and Klinefelter syndrome), and mitochondrial inheritance (for example, epilepsy and dementia).
11 Surprising Things Your Genes Say About YouExplore what role DNA plays in your health, love life, and more in this WebMD slideshow.
Is Amniocentesis Painful?Usually, amniocentesis (removing a small amount of the amniotic fluid that surrounds the baby in the womb) is not painful, and it is done within a few minutes. However, some women may experience mild pain and some discomfort during this procedure.
Is Spinal Muscular Atrophy Treatable?Spinal muscular atrophy (SMA) is a type of motor neuron disease that is hereditary. Treatment of spinal muscular atrophy includes prescription medication, suctioning mucus from the throat, external oxygen support and breathing exercises.
Pregnancy: Prenatal Care and TestsPrenatal care is important for the health of the mother and the baby. Common prenatal tests include ultrasound, amniocentesis, screening for group B strep, and chronic villus sampling. Prenatal care also helps detect health conditions related to pregnancy, such as preeclampsia and gestational diabetes. Prenatal care costs can be expensive, but services are available to help women get the care they need.
Pregnancy: 7 Common Third Trimester TestsTesting is often recommended during the third trimester of pregnancy. These tests are designed to ensure the health and safety of both the child and mother. Common tests during the third trimester of a woman's pregnancy include:
- group B streptococcus screening,
- electronic fetal heart monitoring,
- nonstress test,
- contraction stress test, and
- a biophysical profile.
What Does Amniocentesis Test For?Amniocentesis is a procedure in which a small amount of amniotic fluid (the fluid present around the unborn baby in the uterus) is removed for testing or treatment purposes. The amniotic fluid contains fetal cells and various proteins.
Who Should Get Genetic Counselling?Genetic counseling is the process that helps you in determining hereditary or genetic (running in your family) problems that might affect you or your family. It is done by a trained professional.