Hereditary nephritis associated with low-tone sensorineural hearing difficulty: a case report

The proband was a 14-year-old girl with hematuria and proteinuria. Many members of her maternal pedigree had hematuria and proteinuria. Her mother, younger brother (age 12 years) and younger sister (age 9 years) had microscopic hematuria and proteinuria with normal renal function. Her mother had nephrotic syndrome during pregnancy and a renal biopsy was performed. Light microscopic findings of the renal biopsy specimen revealed mild mesangial proliferation and irregularity of glomerular basement membrane. The pedigree showed no chronic renal failure and no deafness. The proband had experienced microscopic hematuria and occasionally macroscopic hematuria since 3 years of age. Proteinuria increased steadily and at the age of 14 years, she had nephrotic syndrome and renal dysfunction (creatinine clearance of 57.9 ml/min/1.48 m2). Renal biopsy was performed and light microscopic findings showed segmental mesangial cell proliferation and numerous interstitial foam cells without significant findings by immunofluorescent study. Electron microscopic examination showed splitting into many layers and thinning of the glomerular basement membrane. She had no complaint of hearing. However, audiological studies detected bilateral low-tone (from 125 Hz to 1000 Hz) sensorineural hearing difficulty, ranging from 30 to 40 dB. High scores on the short increment sensitivity index (SISI) test suggested inner ear hearing difficulty. Audiogram of her brother revealed also low-tone sensorineural hearing loss. Hereditary nephritis with the characteristic lesion of the glomerular basement membrane and sensorineural hearing difficulty has been known as Alport syndrome. Alport syndrome associated with familial low-tone hearing difficulty has not been reported previously.