Phenotypes and ATP7B gene variants in 316 children with Wilson disease / 中华儿科杂志

Objectives: To summarize the clinical phenotypes and the variation spectrum of ATP7B gene in Chinese children with Wilson's disease (WD) and to investigate their significance for early diagnosis. Methods: Retrospective analysis was performed on the clinical data of 316 children diagnosed as WD in Guangzhou Women and Children's Medical Center during the period from January 2010 to June 2021. The general situations, clinical manifestations, lab test results, imaging examinations, and ATP7B gene variant characteristics were collected. The patients were divided into asymptomatic WD group and symptomatic WD group based on the presence or absence of clinical symptoms at the time that WD diagnosis was made. The χ2 test, t test or Mann-Whitney U test were used to compare the differences between groups. Results: Among the 316 children with WD, 199 were males and 117 were females, with the age of 5.4 (4.0, 7.6) years at diagnosis; 261 cases (82.6%) were asymptomatic with the age of 4.9 (3.9, 6.4) years; whereas 55 cases (17.4%) were symptomatic with the age of 9.6 (7.3, 12.0) years. The main symptoms invloved liver, kidney, nervous system, or skin damage. Of all the patients, 95.9% (303/316) had abnormal liver function at diagnosis; 98.1% (310/316) had the serum ceruloplasmin lever lower than 200 mg/L; 97.7% (302/309) had 24-hour urine copper content exceeding 40 μg; only 7.4% (23/310) had positive corneal K-F rings, 8.2% (23/281) had abnormal MRI signals in the lenticular nucleus, and all of them had symptoms of damage in liver, kidney or nervous system. Compared with the group of symptomatic WD, asymptomatic group had higher levels of serum alanine aminotransferase and lower levels ceruloplasmin and 24-hour urine copper [(208±137) vs. (72±78) U/L, (55±47) vs. (69±48) mg/L, 103 (72, 153) vs. 492 (230, 1 432) μg; t=9.98, -1.98, Z=-4.89, all P<0.001]. Among the 314 patients completing genetic sequencing, a total of 107 mutations in ATP7B gene were detected, of which 10 are novel variants, and 3 cases (1.0%) had large heterozygous deletion (exons 10 to exon 11) in ATP7B gene. The percentage of missense mutation in asymptomatic WD children was significantly higher than that in symptomatic WD (81.5% (422/518) vs. 69.1% (76/110), χ²=8.47, P<0.05). WD patients carrying homozygous variant of c.2 333G>T had significantly low levels of ceruloplasmin than those not carrying this variant ((23±5) vs. (61±48) mg/L, t=-2.34, P<0.001). Conclusions: The elevation of serum ALT is an important clue for early diagnosis of WD in children, while serum ceruloplasmin and 24-hour urine copper content are specific markers for early diagnosis of WD. In order to confirm the diagnosis of WD, it is necessary to combine the Sanger sequencing with multiplex ligation-dependent probe amplification or other testing technologies.

Identification of a novel pathogenic mutation in PDHA1 gene for pyruvate dehydrogenase complex deficiency / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the molecular genetic mechanism and genetic diagnosis of pyruvate dehydrogenase complex deficiency (PHD), and to provide a basis for genetic counseling and prenatal genetic diagnosis of PHD.</p><p><b>METHODS</b>Polymerase chain reaction (PCR) was performed to amplify the 11 exons and exon junction of the PDHA1 gene from a child who was diagnosed with PHD based on clinical characteristics and laboratory examination results. The PCR products were sequenced to determine the mutation. An analysis of amino acid conservation and prediction of protein secondary and tertiary structure were performed using bioinformatic approaches to identify the pathogenicity of the novel mutation.</p><p><b>RESULTS</b>One novel duplication mutation, c.1111_1158dup48bp, was found in the exon 11 of the PDHA1 gene of the patient. No c.1111_1158dup48bp mutation was detected in the sequencing results from 50 normal controls. The results of protein secondary and tertiary structure prediction showed that the novel mutation c.1111 _1158dup48bp led to the duplication of 16 amino acids residues, serine371 to phenylalanine386, which induced a substantial change in protein secondary and tertiary structure. The conformational change was not detected in the normal controls.</p><p><b>CONCLUSIONS</b>The novel duplication mutation c.1111_1158dup48bp in the PDHA1 gene is not due to gene polymorphisms but a possible novel pathogenic mutation for PHD.</p>

Gene mutations and clinical manifestations in children with glycogen storage disease type Ib / 中国当代儿科杂志

<p><b>OBJECTIVE</b>Glycogen storage disease type Ib (GSDIb) is caused by a deficiency of glucose-6-phosphate translocase (G6PT) activity due to SLC37A4 gene mutations. Most GSDIb patients have recurrent infections and inflammatory bowel disease, with poor prognosis. Detection of SLC37A4 gene mutations is of great significance for the diagnosis, subtyping and outcome prediction of GSD patients. This study aims to analyze SLC37A4 gene mutations in Chinese GSDIb patients and to investigate the relationship between its genotypes and clinical manifestations.</p><p><b>METHODS</b>All exons and their flanking introns of SLC37A4 gene in 28 Chinese children with a primary diagnosis of GSDIb were screened by PCR combined with direct DNA sequencing to detect SLC37A4 gene mutations.</p><p><b>RESULTS</b>Five SLC37A4 gene mutations were detected in 7 (25%) of the 28 children, i.e., p.Gly149Glu (9/13, 69%), p.Gly115Arg (1/13, 8%), p.Pro191Leu (1/13, 8%), c.959-960 insT (1/13, 8%) and c.870+5G>A (1/13, 8%).</p><p><b>CONCLUSIONS</b>In this study, c.959-960 insT is a novel mutation and p.Gly149Glu is the most common mutation. p.Gly149Glu may be associated with severe infections in children with GSDIb.</p>

Wolman disease with novel mutation of LIPA gene in a Chinese infant / 中华儿科杂志

<p><b>OBJECTIVE</b>To explore the clinical characteristics of Wolman disease and diagnostic methods using enzymatic and molecular analysis.</p><p><b>METHOD</b>Lysosomal acid lipase activity was measured using 4-methylumbelliferyl oleate in the leukocytes of an infant suspected of Wolman disease and LIPA gene mutational analysis was performed by PCR and direct sequencing in the proband and his parents. After the diagnosis was confirmed, the clinical, biochemical, radiological and histopathological findings in this case of Wolman disease were retrospectively reviewed.</p><p><b>RESULT</b>The sixteen-day-old boy was failing to thrive with progressive vomiting, abdominal distention and hepatosplenomegaly. Abdominal X-ray revealed adrenal calcifications which were confirmed on abdominal CT scan. Xanthomatosis were observed on enlarged liver, spleen and lymph nodes during abdominal surgery. Liver and lymph node biopsy showed foamy histiocytes. The lysosomal acid lipase activity in leukocytes was 3.5 nmol/(mg·h) [control 35.5 - 105.8 nmol/(mg·h)]. Serum chitotriosidase activity was 315.8 nmol/(ml·h) [control 0 - 53 nmol/(ml·h)]. The patient was homozygote for a novel insert mutation allele c.318 ins T, p. Phe106fsX4 in exon 4 on LIPA gene. His both parents were carriers of the mutation.</p><p><b>CONCLUSION</b>The clinical features of Wolman disease include early onset of vomiting, abdominal distention, growth failure, hepatosplenomegaly and bilateral adrenal calcification after birth. A plain abdominal X-ray film should be taken to check for the typical pattern of adrenal calcification in suspected cases of Wolman disease. The enzymatic and molecular analyses of lysosomal acid lipase can confirm the diagnosis of Wolman disease.</p>

Preparation and characterization of specific monoclonal antibodies against hexon of HAdV 3 / 南方医科大学学报

<p><b>OBJECTIVE</b>To obtain the monoclonal antibody against hexon protein of human adenovirus.</p><p><b>METHODS</b>BALB/c mice were immunized with purified recombinant hexon protein, and the spleen cells of the mice were isolated and fused with myloma cells. Four hybridoma cell strains were screened by indirect ELISA and cultured, and the sensitivity, specificity and virus neutralizing activity were analyzed with ELISA, Western blotting and neutralizing test.</p><p><b>RESULTS</b>The mouse ascites produced by these hybridoma cells contained specific monoclonal antibodies against hexon protein of human adenovirus as identified by ELISA and Western blot, and the antibody generated by 4C6 strain showed human adenovirus type 3-neutralizing activity.</p><p><b>CONCLUSION</b>The monoclonal antibodies against hexon protein with high specificity have been successfully obtained, and these antibodies can be useful in developing assays for early diagnosis of HAdV3 infection and also in study of therapeutic drugs of the infection.</p>

Cloning, expression and immunocharacterization of the capsid protein of human Norwalk virus Guangzhou strain NVgz01 / 南方医科大学学报

<p><b>OBJECTIVE</b>To clone, express and characterize the capsid protein of human Norwalk virus Guangzhou strain NVgz01.</p><p><b>METHODS</b>On the basis of successful construction of full-genome clones and sequence analysis of human norovirus Guangzhou strain NVgz01, the full capsid gene was ligated into pET28a (+) for expression. After IPTG induction, the recombinant protein was purified through metal (Ni(2+)) chelating affinity chromatography. Western blotting and enzyme-linked immunosorbent assay (ELISA) were used to determine the antigenicity of the recombinant protein.</p><p><b>RESULTS</b>The recombinant capsid gene was overexpressed in E.coli, yielding the recombinant protein with relative molecular mass of 62x10(3) that was highly purified through metal (Ni(2+)) chelating affinity chromatography. IDEIA Norovirus Kit and immunoassay showed that the recombinant protein had good antigenicity.</p><p><b>CONCLUSION</b>The capsid gene of norovirus Guangzhou strain has been cloned and expressed, which can be useful for developing diagnostic reagents or vaccine of norovirus.</p>