An Acadian variant of Fanconi syndrome

Abstract

The Acadians were French settlers to Nova Scotia in the seventeenth century. In 1755, they were expelled by the British to various sites in the Americas, including Louisiana, where they are referred to as Cajuns. Many later migrated back to the Maritime Provinces of Canada. The objective of this study was to describe a series of pediatric patients representing an Acadian variant of Fanconi syndrome (AVFS). Nineteen children were diagnosed with AVFS between 1971 and 2006 and followed regularly. Data concerning demographics, growth, bone disease, and renal function at presentation and last observation were collected. The commonest reason for referral was assessment of genu valgum at 8.5 ± 4.2 years (mean ± SD) with hypophosphatemic rickets confirmed in all patients. Small-body habitus and short stature were confirmed in all patients. Therapy consisting of alkali replacement and phosphate and vitamin D supplements resulted in improvement of rickets and leg alignment but not stature (median height Z-score at presentation −2.05, range −3.6 to 0.21, vs. −2.05 at last observation, range −3.36 to 0.47). Creatinine clearance decreased (65.4 ± 24.6 vs. 48.0 ± 36.0 ml/min per 1.73 m², P < 0.05) and proteinuria increased (0.38 ± 0.25 vs. 1.46 ± 1.52 g/d, P < 0.05) during follow up of 8.4 ± 6.1 years. Chronic kidney disease developed in 50% by age 13 years. No extrarenal manifestations were identified, although two patients developed lethal pulmonary fibrosis postrenal transplantation. AVFS is characterized by rickets responsive to solute therapy, short stature, and loss of renal function, with progressive proteinuria with age.