Ultra‐rapid emergency genomic diagnosis of Donahue syndrome in a preterm infant within 17 hours

Abstract

Genetic diseases are a major cause of neonatal morbidity and mortality. The clinical differential diagnosis in severely ill neonates, especially in premature infants, is challenging. Next generation sequencing (NGS) diagnostics is a valuable tool, but the turnaround time is often too long to provide a diagnosis in the time needed for clinical guidance in newborn intensive care units (NICU). To minimize turnaround time, we developed an ultra‐rapid whole genome sequencing pipeline and tested it in clinical practice. Our pilot case, was a preterm infant presenting with several crises of dehydration, hypoglycaemia and hyponatremia together with nephrocalcinosis and hypertrophic cardiomyopathy. Whole genome sequencing was performed using a paired‐end 2x75bp protocol. Sequencing data were exported after 50 sequencing cycles for a first analysis. After run completion, the rapid‐sequencing protocol, a second analysis of the 2 x 75 paired‐end run was performed. Both analyses comprised read‐mapping and SNP−/indel calling on an on‐site Edico Genome DRAGEN server, followed by functional annotation and pathogenicity prediction using in‐house scripts. After the first analysis within 17 h, the emergency ultra‐rapid protocol identified two novel compound heterozygous variants in the insulin receptor gene (INSR), pathogenic variants in which cause Donohue Syndrome. The genetic diagnosis could be confirmed by detection of hyperinsulinism and patient care adjusted. Nonetheless, we decided to pursue RNA studies, proving the functional effect of the novel splice variant and reduced expression levels of INSR in patients skin fibroblasts.

A defect in molybdenum cofactor binding causes an attenuated form of sulfite oxidase deficiency

“…Another option would be to include ISOD and other treatable conditions into genomic approaches for screening of inborn errors of metabolism, allow timely treatment prior the manifestation of metabolic crises and irreversible brain damage. 28 By performing western blot and SO activity analysis of patient fibroblasts, we found complete absence of SO activity and SO protein. However, in line with previous reports, our in vitro studies of recombinantly expressed SO confirmed increased enzymatic activity of SO R366H variant in comparison to SO WT.…”

“…Thus ultimately, preclinical studies in murine knock‐in models are required to gain a better understanding of the biomarkers and dietary protocol, also for the metabolic crisis management. Another option would be to include ISOD and other treatable conditions into genomic approaches for screening of inborn errors of metabolism, allow timely treatment prior the manifestation of metabolic crises and irreversible brain damage 28 …”

Molecular Genetic Screening of Neonatal Intensive Care Units: Hyperbilirubinemia as an Example

“…Gene screening programs can contribute to a clear diagnosis as soon as possible. 38 Although there is no specific study for hyperbilirubinemia, gene sequencing in children in NICU has already achieved good results. For example, Dimmock’s group carried out a randomized, controlled trial of genome sequencing in the children with conditions of unknown etiology in NICUs.…”

Hypertrophic Cardiomyopathy in Infants from the Perspective of Cardiomyocyte Maturation

“…Currently, pediatric HCM with gene mutations is often diagnosed, even before presenting symptoms, by genetic study, especially in cases with a family history of HCM among first-degree relatives. 4) 5) Similar to most major guidelines of screening for HCM from the adolescent period to adults, special surveillance for diagnosing infantile HCM is required. 6) …”