Probands tested for HNF1B mutations in the 2005-2018 period (N = 50) were identified in the Polish Monogenic Diabetes Registry, which prospectively recruits primarily pediatric patients and their families on a nationwide scale. Variants that had been reported pathogenic were reassessed using criteria of the American College of Medical Genetics and Genomics (ACMG). A structured medical interview was performed with all available individuals, their parents, and/or their physicians. For each patient, HNF1B score was calculated based on available clinical information.
The study group numbered 36 unrelated probands (28% lost to follow-up): 14 with pathogenic or likely-pathogenic variants in HNF1B, one with a variant of uncertain significance, and 21 negative for HNF1B mutations. Presence of cystic kidneys (OR = 9.17, 95% CI:1.87-44.92), pancreatic abnormalities (OR = 15, 95% CI:1.55-145.23), elevated liver enzymes (OR = 15, 95% CI:1.55-145.23) best discriminated HNF1B-positive cases from the negative ones. Presence of impaired glucose tolerance coupled with kidney disease in the proband and one parent was also highly predictive for HNF1B mutations (OR = 11.11, 95% CI:1.13-109.36). HNF1B-score with recommended cutoff distinguished patients with and without HNF1B findings with 100% sensitivity and 47.6% specificity. Addition of four clinical variables to select patients based on HNF1B score improved specificity to 71.4% (95% CI:47.8%-88.7%) while retaining 100% sensitivity.
Detailed medical interview may enable more accurate patient selection for targeted genetic testing.