OBJECTIVE: To detect variant of TRNT1 gene in a child featuring sideroblastic anemia with B-cell immunodeficiency, periodic fever and developmental delay (SIFD). METHODS: The proband and his parents were analyzed through trio-whole exome sequencing. Sanger sequencing and bioinformatic analysis were carried out to verify the candidate variant sites associated with the clinical phenotype. RESULTS: Genetic testing showed that the proband has carried compound heterozygous variants of the TRNT1 gene, namely c.88A>G(p.Met30Val) and c.363G>T(p.Glu121Asp). Sanger sequencing confirmed that the variants were respectively inherited from his father and mother. The variants were unreported previously. By bioinformatic analysis, both variants were predicted to affect the stability of binding of the TRNT1 protein with tRNA. Based on the American College of Medical Genetics and Genomics standards and guidelines, c.88A>G and c.363G>T variants of TRNT1 gene were predicted to be uncertain significance (PM2+PP3+PP4) and likely pathogenic (PM1+PM2+PP3+PP4), respectively. CONCLUSION The c.88A>G (p.Met30Val) and c.363G>T(p.Glu121Asp) compound heterozygous variants of the TRNT1 gene probably underlay the disease in this patient. Above finding has enriched the spectrum of TRNT1 gene variants.
Genetic Testing ; Humans ; Nucleotidyltransferases

Objective:Four cases with NLRP3-related autoinflammatory diseases were reported to summarize the clinical characteristics, genotype, and treatment responses of the disease, and to improve clinical pediatricians' understanding of the disease.Methods:A retrospective analysis was performed on 4 cases with NLRP3-related autoinflammatory diseases diagnosed in Children's Hospital of Anhui Province in 2016—2021, and the clinical features and treatment progress of NLRP3-related autoinflammatory diseases were retrospectively analyzed based on the clinical features, gene reports, and literature review.Results:① All 4 cases were male. Cases 1, 2, and 3 had the disease onset after birth, and case 4 had the disease onset 6 months after birth. All showed periodic fever, repeated urticaria-like rash, protruding forehead, and saddle nose. White blood cells count, erythrocyte sedimentation rate, and C-reactive protein were increased during the attack period, and those in the interval period were normal, and antibiotic treatment was ineffective. ② The genetic test of all these 4 children showed NLRP3 mutation. Children 1, 2, and 3 were heterozygous mutations, and their parents were wild-type. The mutation was located at chromosome Chr1: 247587658, exon c913 (exon3). G>A, the 305th aspartic acid (Asp) of the protein was changed to asparagine (Asn) in child 1. The mutation was located at the chromosomal Chr1: 247588072, the nucleic acid was changed to c1327(exon3)T>C, and the amino acid was changed to p.Y443H in cases 2 and 3. Somatic heterozygous mutation was found in case 4, and the child's parents were wild-type. In this case, the mutation was located at chromosomal Chr1: 247587658, exon3 G>A, and the 305th Asp of the protein was changed to Asn. ③Children in cases 1, 2, and 3 were treated with glucocorticoids and non-steroidal anti-inflammatory drugs at the initial stage, but the effects were limited. After receiving IL-1 antagonist treatment fever, skin rash, joint swelling and pain disappeared, and the inflammatory indexes were returned to normal. The child 4 received non-steroidal anti-inflammatory drugs and methotrexate, but he failed to respond to the treatment. Treatment with tocilizumab was not effective, however, fever, skin rash, or joint pain disappeared after treated with Khanna.Conclusion:①NLRP3-related autoinflammatory diseases can cause periodic fever, urticaria, joint involvement, and severe involvement of the central nervous system and organ amyloidosis. Which are early misdiagnosis is prone to systemic juvenile idiopathic arthritis. ②The disease was an inflammatory disease mediated by interleukin-1. At present, non-steroidal anti-inflammatory drug, glucocorticoid and chronic anti-rheumatic drugs have limited effects. IL-1 antagonists are effective and safe in the treatment of the disease.