What Is Trio-exome Sequencing?

Genetic conditions often present confusing symptoms. ¹ And in such cases, giving a clear & precise diagnosis becomes a big challenge.² This is especially true among infants admitted to Neonatal ICUs. Therefore, we need an advanced level test that can carefully analyze these symptoms for a proper diagnosis. And that's exactly what trio-exome sequencing is! As the name suggests, Trio-exome sequencing analyses genetic data from 3 people, including the baby, its mother, and the father. It is a powerful tool to identify variations in DNA that are known to cause specific inherited genetic conditions.

Unlike Singleton-Exome sequencing, which only analyzes a baby’s genetic data, trio-exome sequencing or trio analysis collects & analyzes genetic data from the child as well as its biological parents. Although slightly more expensive, it serves as a better alternative to singleton-exome sequencing by providing an additional 10-15% increase in the diagnostic yield. ³ This is extremely beneficial for patients who are still undiagnosed after singleton-exome sequencing and, in fact, proves to be a less expensive option in such cases.

Expediting the overall diagnostic journey for a critically ill baby, this advanced technology aims to find & study differences between the DNA of the affected baby and its unaffected parents. These differences are nothing but variations associated with different genetic conditions that can be passed down from parents to their children. Such unaffected parents are referred to as carriers of the condition. They carry these variations in their genes but do not present any related symptoms. ⁴

Trio-exome sequencing targets thousands of genes at once using the advanced Next-Gen sequencing technology. Reading one nucleotide (structural or building block of our DNA) at a time, it builds a sequence of DNA that is compared to similar genetic sequences obtained from the parents. Both the baby’s & the parents DNA sequence is then compared to the normal standard/reference sequences. 

This comparison helps board-certified geneticists to study variations that can be linked to a baby's medical concern. Such thorough analysis reduces the chance of error and specifically targets potential disease-causing variations. Simply put, trio-exome sequencing offers an advanced approach for detecting inherited variations that may become a cause of illness in babies.

Trio exome sequencing boasts a high diagnostic yield of around 37%. ²  Therefore, it serves as a great way to give an early & accurate diagnosis for unclear or unexplained symptoms presented among babies admitted to Neonatal ICUs. ⁵ 

According to a study among a pediatric population of 208 patients, singleton sequencing presented a diagnostic yield of 41%, in contrast to trio-exome sequencing at 47%. ⁶

LifeCell's advanced GenomeScope Trio test can serve as the ultimate first-line test for critically-ill infants with a suspected genetic condition. Our rapid trio-exome sequencing facility aims to deliver a faster and more accurate diagnosis for infants admitted to NICUs in urgent need of intervention/treatment. 

This test uses genomic DNA extracted from the baby's as well as its parents' blood. It captures and sequences all the genes by utilizing the NGS technology and delivers results with a detection rate of >95% and reporting accuracy of >99% (Q30).

GenomeScope Trio test analyzes 6000+ clinically relevant genes associated with various childhood-onset conditions and boasts a turnaround time of just 5 days.

For a precise diagnosis of a genetic condition, the gene carrying the variation must be known, detectable, and captured by the sequencing technology in use. Trio-exome sequencing has become an established method of detecting genetic conditions among critically ill babies, fulfilling the above criteria.

GenomeScope Trio uses the same technology to deliver quick insights into the health and cause of illness for such babies. Moreover, this data can be conveniently reanalyzed if the baby develops new symptoms in the future. LifeCell offers one-time free-of-cost re-analysis within a year from the baby's birth, only including genes specific to symptoms of the condition. A copy of the data is shared on a removable hard drive for an additional fee of INR 2,000.