RENAL INVOLVEMENT IN CHILDREN WITH GLYCOGEN-STORAGE DISEASE

Abstract

INTRODUCTION: Long-term complications of glycogen-storage diseases (GSDs) include delayed puberty, hepatic adenomata, and renal disease. OBJECTIVE: In this study, our aim was to detect renal involvement in children with GSD and to determine the most accurate laboratory test to be the gold standard for early detection of this renal dysfunction. METHODS: Twenty-seven children known to have GSD were included in this study. Fifteen healthy age- and gender-matched children were also included as controls. Routine urine analysis and measurement of urinary β2-microglobulin and microalbumin levels were performed for all patients and controls. Renal-function tests, measurement of serum electrolyte, alkaline phosphatase, urinary calcium, blood, and urine pH levels, creation of a urinary and plasma aminogram, calculation of the glomerular filtration rate, bone radiography to detect rachitic manifestations, and abdominal ultrasound to measure renal size were performed for all patients. RESULTS: Twenty-one patients had ≥1 renal abnormality. The most common was increased urinary β2-microglobulin level (15 of 21) followed by an abnormal glomerular filtration rate, whether low or high (8 of 21), and microalbuminuria (6 of 21). Sonographically, there was nephrocalcinosis in 1 case and renal stone in another. The area under the receiver operating characteristic curve for β2-microglobulin was 0.86 (P = .01) and 0.7 for the urinary microalbumin/creatinine ratio (P = .15). The best cutoff level for predicting renal abnormality for urinary β2-microglobulin was 0.22 mg/L with 70% sensitivity and 100% specificity, and the best cutoff value for the urinary microalbumin/creatinine ratio was 4.5 with 86% sensitivity and 50% specificity. CONCLUSIONS: Renal abnormalities are common in patients with GSD. Urinary B2-microglobulin level can be considered the gold standard for early detection of renal dysfunction in these patients.