Very-early-onset autosomal dominant polycystic kidney disease coexisting with congenital adrenal hyperplasia in a newborn: a case report.

This case report describes a newborn diagnosed with very-early-onset autosomal dominant polycystic kidney disease (VEO-ADPKD) and congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency. The patient presented with prenatally detected kidney cysts and exhibited clinical and laboratory features consistent with salt-wasting, including markedly elevated 17-hydroxyprogesterone levels, requiring treatment with hydrocortisone, fludrocortisone, and sodium chloride. Genetic analysis revealed a de novo truncating variant in PKD1 and two variants in CYP21A2. Hypertension developed at 3 years and 7 months despite unchanged steroid replacement doses, requiring antihypertensive treatment, and resolved after mineralocorticoid dose reduction. This case highlights the competing therapeutic demands of concurrent salt-wasting CAH and VEO-ADPKD, underscoring the importance of early genetic evaluation and integrated multidisciplinary surveillance.