Recently, a renal-biopsy specimen from a patient that was diagnosed with cubulin deficiency and a homozygous mutation in cubilin showed no immunologic reaction for cubulin and abnormal cytoplasmic and vesicular distribution of amnionless with no developmental defects [99], suggesting that cubilin may not be required for normal human development. The gene discussed is CUBN; the disease is hyperinsulinemic hypoglycemia, familial, 4.