X-linked Adrenoleukodystrophy (X-ALD) is Added to the Newborn Screen in Illinois

October 1, 2019

By Rachel Hickey, Vera Shively and the Genetic Counseling Team at Lurie Children’s

The health and well-being of all babies is important from the start. This is why newborn screening began in the United States in 1963.

What Is Newborn Screening?

Newborn screening can change a baby’s life. It is testing that is done shortly after birth to help detect serious health conditions before obvious symptoms appear. Conditions are added to the newborn screen when early diagnosis and treatment are likely to improve the child’s health. It is a public health service, run separately by each state. Babies are usually tested about 24 hours after birth. Newborn screening in Illinois consists of 3 parts:

Blood Sample A heel stick is done to collect a small blood sample which is then tested in a state laboratory to screen for many medical conditions. The number of conditions on the newborn screen varies by state. Currently Illinois screens for 63 different conditions.
Oxygen Test A soft oxygen sensor is wrapped around the baby's right hand and one foot for about 5 minutes to estimate the amount of oxygen in the baby’s blood. The test is done to help identify babies that may have critical congenital heart disease.
Hearing Test A hearing screen is done with special head phones to see if the baby responds to sound.

A newborn screening test cannot confirm or rule out whether a baby has a condition. Like most screening tests, its purpose is to identify those babies who are at higher risk of having a condition. Once your baby has a positive result on the newborn screen, they will be referred to a specialist who will evaluate them and obtain further testing to see if your child is truly affected with the condition and requires medical follow-up.

What Is X-ALD?

X-ALD is a genetic disorder that affects the nervous system (brain and spinal cord) and adrenal glands. Children with X-ALD are not able to break down very long chain fatty acids (VLCFAs). When VLCFAs cannot be broken down, they build up inside the cells and affect the cells ability to make myelin. Myelin acts like the insulation of an electrical wire. It helps nerve signals travel from one nerve cell (neuron) to the next, and from neurons to muscles. As myelin is lost in patients with X-ALD, the communication between neurons and muscle cells becomes impaired, impacting brain function and movement.

The adrenal glands produce hormones (chemical messengers), such as cortisol. Cortisol has many important roles in the body, including regulating your blood sugar levels, controlling your blood pressure and reducing inflammation. It’s often referred to as the stress hormone since it is released when our bodies encounter stressful situations like an infection or injury. In X-ALD, the VLCFAs can also build up in the adrenal glands, which prevents the glands from making enough cortisol. This can lead to serious health problems.

Why Was It Recently Added to the Newborn Screen?

Illinois was the 12^th state to add X-ALD testing to the newborn screen. After careful consideration, including input from parents who have children with X-ALD, Illinois decided that the benefits of screening outweighed its risks. There is treatment available for children with X-ALD. The treatment is only effective if a child is diagnosed early, before they start having symptoms of X-ALD.

What Happens When a Newborn Baby Has a Positive Screen for X-ALD?

A team of specialists at Lurie Children’s evaluates newborns who have tested positive for any condition on the newborn screen, including X-ALD. The team will explain the newborn screening test results, examine the baby, arrange follow-up diagnostic testing and provide guidance and counseling to parents. Babies who screen positive for X-ALD will need to have a blood draw to measure VLCFA levels. If the VLCFAs are high, it is likely that the baby has X-ALD. Genetic testing is then obtained to further confirm the diagnosis. Babies diagnosed with X-ALD will be evaluated by the Neurology and Endocrinology teams at Lurie Children’s. At first babies with X-ALD do not have any symptoms of the condition. The symptoms of X-ALD occur over time and careful monitoring through blood tests and MRI studies are recommended as the child grows.

Learn more about the Genetic Counseling Team