Keratomalacia in a child with familial hypo-retinol-binding proteinemia

Retinol-binding protein (RBP) is a plasma protein with a molecular weight of 21,000 synthesized in the hepatocytes, binding with retinol (vitamin A), and transporting retinol to peripheral tissues. Keratomalacia is caused by a deficiency of vitamin A itself and/or protein-calorie malnutrition. In the latter condition, production of RBP is inhibited. We report herein familial hypo-retinol-binding proteinemia in a child aged 19 months who developed keratomalacia during measles infection in spite of good nourishment. To the best of our knowledge this is the first description of such a case. The patient, her sister and mother showed persistent low levels, about half the normal levels, of retinol and RBP which were unresponsive to oral vitamin A and protein-rich diet. They had normal liver function tests, normal serum levels of other proteins and fat-soluble vitamins and lipids. This hypo-retinol-binding proteinemia was thought to predispose the child to develop keratomalacia during measles. Family members would be heterozygous with one normal RBP gene and one defective RBP gene.