Unbiased phenotype and genotype matching maximizes gene discovery and diagnostic yield.

PURPOSE: Widespread application of next-generation sequencing, combined with data exchange platforms, has provided molecular diagnoses for countless families. To maximize diagnostic yield, we implemented an unbiased semi-automated genematching algorithm based on genotype and phenotype matching. METHODS: Rare homozygous variants identified in 2 or more affected individuals, but not in healthy individuals, were extracted from our local database of ∼12,000 exomes. Phenotype similarity scores (PSS), based on human phenotype ontology terms, were assigned to each pair of individuals matched at the genotype level using HPOsim. RESULTS: 33,792 genotype-matched pairs were discovered, representing variants in 7567 unique genes. There was an enrichment of PSS ≥0.1 among pathogenic/likely pathogenic variant-level pairs (94.3% in pathogenic/likely pathogenic variant-level matches vs 34.75% in all matches). We highlighted founder or region-specific variants as an internal positive control and proceeded to identify candidate disease genes. Variant-level matches were particularly helpful in cases involving inframe indels and splice region variants beyond the canonical splice sites, which may otherwise have been disregarded, allowing for detection of candidate disease genes, such as KAT2A, RPAIN, and LAMP3. CONCLUSION: Semi-automated genotype matching combined with PSS is a powerful tool to resolve variants of uncertain significance and to identify candidate disease genes.

Serious Bacterial Infections in Preterm Infants: Should Their Age Be "Corrected"?

Adjusting the chronological age of preterm infants according to their gestational age is a widely accepted practice in the field of neurodevelopment. It has been suggested for the assessment of preterm infants with suspected infection, but has been poorly validated. Correcting for chronological age is especially critical in infants with a chronological age above 3 months, but a corrected age below 3 months due to the differences in assessment protocols. This study assessed the difference in incidence of serious bacterial infection (SBI) according to chronological and corrected age in preterm infants. A retrospective analysis of pediatric emergency department (PED) presentations was conducted for all 448 preterm infants born in between January 2010 and August 2019. Of the 448 preterm infants, 204 (46%) presented at one of 3 PEDs in Jerusalem, Israel, during their first year of life. Overall, 141 (31.4%) presented with fever and were included in the study. The infants were divided into 3 age groups: 1-corrected age >3 months; 2-chronological age >3 months, but corrected age <3 months; 3-chronological and corrected age <3 months. SBI was diagnosed in 2.6%, 16.7%, and 33.3% of the infants in groups 1, 2 and 3, respectively; (p < 0.01, p = 0.17, p < 0.001). The incidence of SBI in the control group of 300 term infants <3 months presenting to the PED due to fever was 15.3%. Preterm infants with a corrected age <3 months are at increased risk for SBI, similarly to term infants <3 months of age. Age correction should thus be considered for preterm infants presenting with fever.