[Clinical validation of the 2020 diagnostic approach for pediatric autoimmune encephalitis in a single center].

Objective: To evaluate the value of the 2020 diagnostic criteria (Cellucci criteria) for pediatric autoimmune encephalitis (AE) in children with suspected AE in a single center. Methods: The clinical data of 121 children hospitalized at the First Affiliated Hospital of Zhengzhou University from October 2019 to October 2021, with a diagnosis of suspected AE, were retrospectively collected and analyzed. The children were divided into definite antibody-positive AE (dAPAE), probable antibody-negative AE (prANAE), possible AE (pAE) and non-AE groups according to the Chinese expert consensus and the Graus criteria. A new diagnosis was made according to the Cellucci criteria which was compared with the clinical diagnosis to evaluate the diagnostic value of the Cellucci criteria. The Mann-Whitney U test, Kruskal-Wallis test, and χ2 test were used to compare the differences among groups. The sensitivity and specificity were used to evaluate efficacy of the Cellucci criteria. Results: Among the 121 children, 72 were males and 49 were females, with an age of 10.3 (6.5, 14.0) years at disease onset. There were 99 cases diagnosed as AE according the clinical diagnosis (58 males and 41 females), of which 43 cases were diagnosed as dAPAE, 14 cases as prANAE and 42 cases as pAE, and the other 22 cases were not AE (14 males and 8 females). The top 2 initial symptoms in the 99 children with AE were seizures (53 cases, 53.5%) and abnormal mental behaviors (35 cases, 35.4%). And the most common symptoms during the course of the disease were abnormal mental behaviors (77 cases, 77.8%) and seizures (64 cases, 64.6%). There were statistically differences in the incidence of consciousness disorders, autonomic dysfunctions during the course of the disease and the length of hospitalization among the 4 groups (χ2=21.63, 13.74, H=22.60, all P<0.05). Ninety-six of the 121 children were tested for AE-related antibodies, of which 45 cases (46.9%) were antibody-positive. According to the Cellucci criteria, 42 cases were diagnosed as dAPAE, 34 cases as prANAE and 14 cases as pAE. Compared with the clinical diagnosis, the sensitivity of the Cellucci criteria for the diagnosis of the 3 types of AE were 93.02%, 92.86% and 87.88%, and the specificity were 96.23%, 74.39% and 86.36%, respectively. Conclusions: The Cellucci criteria has a high sensitivity and specificity for the diagnosis of pAE and dAPAE in the clinical management of children with suspected AE, while a high sensitivity but low specificity for the diagnosis of prANAE. Therefore, it is recommended to apply the Cellucci criteria selectively in clinical practice according to the actual situation, especially in the diagnosis of prANAE.

Prenatal diagnosis based on HPRT1 gene mutation in a Lesch-Nyhan family.

We explored the feasibility of applying gene diagnosis in prenatal diagnosis by analysis of hypoxanthine-guanine phosphoribosyltransferase-1 (HPRT1) gene mutation in a Chinese Lesch-Nyhan family. A homozygous mutation of p.R170X (c.508C＞T) in HPRT1 gene was detected in the proband, and a heterozygous mutation of p.R170X was detected in his mother. This mutation failed to be found in the 50 unrelated healthy individuals. Prenatal diagnosis indicated that the foetus was male and also carried p.R170X (c.508C＞T) mutation, same as the proband. Parents of the foetus decided termination of pregnancy, and the result of gene analysis for the aborted tissue was consistent with that of prenatal diagnosis. We can see that Lesch-Nyhan syndrome (LNS) is caused by non-sense mutation p.R170X（c.508C＞T）in HPRT1 gene in this family. Prenatal gene diagnosis is a valid strategy to prevent LNS because it can avoid the birth of LNS foetuses.