tested, and to investigate if any of those features corresponded with a greater likelihood of predicting a genetic diagnosis. Information was obtained by accessing electronic clinical records. Of the 99 children who had genetic testing, 5 children were excluded due to insufficient available information. The characteristics that were assessed in the 94 remaining children included: hearing loss or visual problems either in the proband or in first degree relatives, proteinuria at the time of referral, family history of renal disease, abnormal renal function, hypertension and proteinuria, and a history of previous urinary tract infections. The probability of certain characteristics being associated with an underlying genetic diagnosis was evaluated by calculating likelihood ratios Results Of the 94 children, 65% were male. Median age was 9 years (range 9 months-16 years). Median time from haematuria onset to referral to the tertiary nephrology centre was 7 months (range 1-108 months) and median time from referral to genetic testing was 8 months (range 1-86 months). 28% of the children were found to have an underlying genetic cause of their haematuria or had genetic variants of yet unknown clinical significance (VUS). In the children who had VUS, 38% of mutations were in COL4A3, 31% in COL4A4, 15% in COL4A5, 8% in COL4A6 and 8% in NPHS2. Of the characteristics analysed, co-existing visual problems demonstrated a notable increased likelihood of a genetic diagnosis (likelihood ratio=25). Co-existing family history of renal disease only led to a marginal increased likelihood of a genetic diagnosis (likelihood ratio=1.87). Conclusion This is the largest single centre review to date correlating clinical phenotype in children with persistent haematuria with COL4 genetic testing. From this we can infer that children who present with haematuria should have an early ophthalmological assessment and those who also have visual impairment should be prioritised for genetic testing to assess for variations in the COL4A genes as this increases the pretest probability of a positive genetic result.

Objectives: This study aimed to evaluate the prevalence of acute kidney injury (AKI) and hemolytic uremic syndrome (HUS) in severe pediatric pneumonia due to Streptococcus pneumoniae and to identify factors associated with AKI and HUS in these patients. Methods: We retrospectively analyzed pediatric patients who were admitted to our pediatric intensive care unit due to severe pneumococcal pneumonia between 2013 and 2019. Results: Forty-two patients with a median age of 4.3 years were included. Among these patients, 14 (33.3%) developed AKI, including seven (16.7%) stage 1, two (4.8%) stage 2, and five (11.9%) stage 3 AKI. Features of HUS were present in all of the patients with stage 3 AKI, and four required renal replacement therapy (RRT), with a median duration of 10.5 days (range 3 to 16 days). All patients with HUS required mechanical ventilation and inotropic supports. Patients with lower leukocyte and platelet counts, serum sodium and bicarbonate levels, positive urine dipstick (heme or protein ≥ 2 + ), and presence of bacteremia were associated with stage 2 and 3 AKI. Conclusions: Pediatricians should be aware of the relatively high prevalence of kidney involvement in severe pneumococcal pneumonia, with one-third having AKI and 11.9% developing HUS. Majority (80%) of HUS patients required RRT. Positive urine dipstick, serum sodium, and bicarbonate at presentation, which can be measured in point-of-care tests, may potentially be useful as quick tests to stratify the risks of moderate-to-severe AKI.