Focal segmental glomerulosclerosis and neurogenic bladder in a Chinese patient with a novel de novo pathogenic variation in TRIM8 gene: A case report

Abstract

To report a novel variation in the TRIM8 gene in a Chinese patient who developed focal segmental glomerulosclerosis (FSGS) and neurogenic bladder. Retrospective analysis of the clinical manifestations, laboratory results, renal biopsy results, and genetic data of the patient with FSGS complicated with neurogenic bladder. The patient was a 6-year and 8-month-old Chinese Zang ethnic boy with low-set ears, widely-spaced eyes (inner canthal distance exceeds the 95th percentile of normal inner canthal distance), a small jaw, and a short neck. He could not walk and speak complete sentences until age of 2 years. At age of 4 years, the boy was noticed to have daytime urinary incontinence, hesitancy, and urgency. Combined with urodynamic examination and magnetic resonance imaging examination results, the patient was diagnosed with a neurogenic bladder. Proteinuria was also found. The levels of uric acid, serum creatinine, and blood urea nitrogen were increased. Vitamin D deficiency, hypokalemia, hypocalcium, and hypophosphorus were detected. Urinary ultrasound showed shrinkage of both kidneys. After hospital admission, he was diagnosed with FSGS and stage 3b chronic kidney disease (CKD). Eight months after the first diagnosis, the disease progressed to stage 5 CKD. Gene analysis using whole-exome capture and sequencing revealed a de novo heterozygous pathogenic variation in the TRIM8 gene [NM_030912.2.2:c.1484G>A (p.RP495 *)]. This pathogenic TRIM8 variation and the combined clinical manifestations of neurogenic bladder and FSGS have not been previously reported in the literature. We report a rare Chinese case of FSGS and neurogenic bladder associated with a novel de novo heterozygous variation in the TRIM8 gene. The findings expanded the clinical spectrum of TRIM8 pathogenic variations.