What's the key to helping newborn babies and young children with medical conditions such as seizures, birth defects or delayed development get the best medical care, the newest treatments, or to helping families of a child with a rare disease anticipate the path of their child's condition? The key is making a precise genetic diagnosis.

Millions of children are born each year with rare genetic conditions caused by changes, or variants, somewhere in their DNA, or the string of four letters, A, C, T, and G, that makes up their genetic code. The genetic code provides information on how our bodies grow, develop and function. Most variants have no effect on health. Some variants can result in medical conditions such as birth defects, heart disease or epilepsy.

How is a precise genetic diagnosis made?

Making a precise genetic diagnosis means finding these DNA variants that result in medical conditions. The fastest way to make a precise genetic diagnosis is to test the entire collection of DNA, or genome, of a child and do it as soon as they are suspected of having a genetic condition. The best way to test the genome is by reading, or sequencing, every letter in DNA — a process called "genome sequencing."