Sometimes a child’s brain scan is normal, or shows changes without a clear cause, and routine blood and urine tests don’t give an answer either. For many families this is a long and tiring search. An exome test (whole exome sequencing, or WES) can sometimes find the reason.
What is the exome?
The exome is the small part of our DNA that contains the instructions for making proteins. It is a small part of the whole, but it is where most known disease-causing gene changes are found. That is why testing it can be so useful.
Experience from Egyptian children
Dr. Walaa took part in published research, carried out with Egypt’s National Research Centre, that used exome testing in 763 Egyptian children with developmental regression, difficult-to-control seizures or vision problems. The work helped:
- find rare gene changes behind conditions affecting the brain’s white matter and other rare neurological conditions;
- build a step-by-step approach that helps doctors tell brain injury around birth apart from inherited conditions;
- spare families repeated, unfocused testing, and give clearer advice for future pregnancies.
When might your child’s doctor suggest WES?
- Seizures that start early in life and don’t settle with several medicines.
- Loss of skills, such as walking, sitting or talking, after a period of normal development.
- Parents who are related, or other children in the family with a similar condition.
- Brain scan changes that suggest a genetic or metabolic cause.
Understanding the report
The report needs to be read alongside your child’s symptoms and examination. Results usually fall into one of these groups:
- A disease-causing change was found: it explains the condition and helps guide care.
- A change of uncertain significance: science cannot yet say whether it matters. Testing both parents can often help.
- Nothing was found: this does not always rule out a genetic cause. Sometimes the data is looked at again later, or a wider test is suggested.