A Rare De Novo Mutation in the TRIM8 Gene in a 17-Year-Old Boy with Steroid-Resistant Nephrotic Syndrome: Case Report.

Idiopathic nephrotic syndrome is the most common chronic glomerular disease in children. Treatment with steroids is usually successful; however, in a small percentage of patients, steroid resistance is observed. The most frequent histologic kidney feature of steroid-resistant nephrotic syndrome (SRNS) is focal segmental glomerulosclerosis (FSGS). Genetic testing has become a valuable diagnostic tool in defining the etiology of SRNS, leading to the identification of a genetic cause. The TRIM8 gene is expressed in various tissues, including kidney cells and the central nervous system (CNS). An association between a mutation in the TRIM8 gene and an early onset of FSGS has been proposed but is not well described. We present a 17-year-old boy with epilepsy, early mild developmental delay, a low IgG serum level, and proteinuria, secondary to FSGS. A Next-Generation Sequencing (NGS)-based analysis revealed a heterozygous de novo pathogenic variant in the TRIM8 gene (c.1200C>G, p.Tyr400Ter). TRIM8 gene sequencing should be considered in individuals with early onset of FSGS, particularly accompanied by symptoms of cortical dysfunction, such as epilepsy and intellectual disability.

Diagnostic Methods of Global Developmental Delay Caused by 10q24.3 Heterozygous Loss： A Case Discussion / 中山大学学报(医学科学版)

ObjectiveTo discuss the diagnostic methods of global developmental delay caused by 10q24.3 heterozygous loss. MethodsA retrospective analysis was conducted on the clinical data of one child with global developmental delay， and the results of low depth whole-genome copy number variation sequencing （CNVseq） and family whole exome sequencing （WES） of the child and his parents. ResultsThe patient was a 10-month-old male with developmental retardation in four areas， with some special features （ocular hypertelorism， strabismus， flat nose bridge， protruding forehead， cleft palate， high palatal arch， etc.） and hypotonia of limbs. The CNVseq and WES test showed that the patient had new 10q24.3 heterozygosis loss. Because this region contains the gene SUFU associated with basal cell nevus syndrome and the gene CNNM2 associated with hypomagnesemia， seizures， and mental retardation， and the gene TRIM8 associated of Focal segmental glomerulosclerosis with neurodevelopmental syndrome， we speculated that the cause of the disease in the child was highly related to the heterozygosity deletion of SUFU gene and CNNM2 gene and TRIM8 gene. ConclusionGenetic testing should be improved as soon as possible for children with global developmental delay and special facial manifestations， so as to make clear diagnosis and to judge prognosis.

Two Children With Steroid-Resistant Significant Proteinuria Due to Nonsense Mutations of the TRIM8 Gene: A Case Report and Literature Review.

Background: TRIM8 gene mutations have been reported as the genetic basis of autosomal dominant (AD) neuro-renal syndrome in children, which presents with epileptic encephalopathy, focal segmental glomerulosclerosis (FSGS), developmental delay, and mental retardation. In this study, we report the cases of two children with significant proteinuria due to de novo nonsense mutations of the TRIM8 gene. Case Presentation: Case 1 was a 7-year-old girl who presented with proteinuria and developmental delay, and her renal biopsy showed FSGS. She developed end-stage renal disease (ESRD) 3 years after onset. Case 2 was another 7-year-old girl who developed proteinuria only at age 3, and renal biopsy showed glomerular segmental mesangial proliferative lesions. The two girls underwent genetic testing but we did not find a positive result in the whole exon. However, cluster analysis revealed two new nonsense mutations of the TRIM8 gene (c.1461C>A, p.Tyr 487* and c.1453C>T, p.Gln485*). Conclusions: We reported the clinical manifestation of this neuro-renal syndrome for the first time in China. It is necessary to perform genetic testing in children with steroid-resistant significant proteinuria to identify its etiology and avoid the side effects of immunosuppressants.