Quest and Personalis dive into exome sequencing for rare pediatric neurological disorders

Quest Diagnostics' ($DGX) Athena division is launching a whole-exome sequencing system from Bay Area genomics lab Personalis that helps diagnose rare neurological disorders in children.

Personalis' Neurome product is the first whole-exome sequencing system available through Quest's Athena division, which focuses on diagnostics for neurological conditions. Unlike whole-genome sequencing, which looks at single-nucleotide variants or alterations in DNA sequences, exome sequencing focuses on codes for proteins and specific segments of DNA where disease-causing variants occur. Neurome uses Personalis' ACE Exome technology to screen certain areas of the genome that affect the nervous system, potentially providing diagnoses for certain forms of developmental delay, epilepsy and muscular dystrophy.

Personalis CEO John West

Although exome sequencing is still catching on in the industry, real-life applications of the technology show promise, Personalis CEO John West told FierceDiagnostics. West mentioned a case of an infant who had long QT syndrome, a rare, inherited heart condition that causes abnormally fast heartbeats. The infant had a heart transplant and its blood was sent for whole-genome sequencing, but physicians could not find a diagnosis. Personalis' lab looked at the sample with its exome sequencing technology, uncovering a mutation in 7% of the baby's cells which led to the correct diagnosis. Tools such as ACE Exome allow clinicians to "go deeper," West said, picking up on regions that could be overlooked by traditional screening.

Menlo Park, CA-based Personalis touts positive numbers for its ACE Exome method, presenting data in September at the National Society of Genetic Counselors showing that ACE Exome had a 57% detection rate when identifying gene variants in 83 patient samples, compared to a 25% detection rate from an alternative whole-exome sequencing method in a study of 504 patients. And ACE Exome could screen more coded DNA bases in more depth than whole-genome sequencing or two standard exome screening tools, Quest said in a statement.

Next up, Quest and Personalis plan to process their first patient samples using Neurome to screen for rare neurological diseases. The companies will focus on neurological conditions for the time being but could later expand the collaboration to apply the technology to other diseases.

"We expect to ramp up the product moving forward as we see other opportunities," West told FierceDiagnostics. "We hope to work with Quest to broaden out the opportunities in the future."

-- Emily Wasserman (email | Twitter)