Milky white serum in an infant with anasarca: a case report

Milky white serum in infancy is rare and usually reflects a metabolic disorder; renal causes are distinctly uncommon. We report a 7-month-old male infant who presented with generalized edema and strikingly lipemic serum. Examination revealed lipemia retinalis, while investigations showed extreme hypertriglyceridemia and nephrotic range proteinuria. Initial tests also suggested hyperproteinemia and hyperphosphatemia, but repeat measurements confirmed hypoalbuminemia. Whole exome sequencing identified compound heterozygous variants in the NPHP1 gene, comprising one pathogenic variant and one variant of uncertain significance. Although parental testing was not performed, the combined clinical and genetic findings supported a diagnosis of congenital nephrotic syndrome. Parental testing, though not performed, combined clinical and genetic findings supported a diagnosis of congenital nephrotic syndrome. This case highlights that, although rare, congenital nephrotic syndrome can present with severe dyslipidemia and milky serum in infancy, and underscores the need to recognize potential laboratory estimation errors in lipemic samples.