Quantification of the iduronate-2-sulfatase activity in prenatal diagnosis of mucopolysaccharidosis type Ⅱ / 中华实用儿科临床杂志

Objective:To evaluate the activity of iduronate-2-sulfatase (IDS) in fetal villi and peripheral blood plasma of pregnant women at high risk of mucopolysaccharidosis type Ⅱ (MPS Ⅱ), and to discuss the application of gene analysis in prenatal diagnosis of MPS Ⅱ.Methods:The enzymatic testing and gene analysis results of 23 pregnant women at high risk of MPS Ⅱ, who underwent prenatal diagnosis in Guangzhou Women and Children′s Medical Center from February 2013 to December 2020, were analyzed retrospectively.The IDS activity in fetal villi (30 cases) and plasma (28 cases) was detected by artificial substrate fluorescence.The IDS activity in fetal villi (28 cases) and plasma (34 cases) of normal pregnant women was taken as control.Meanwhile, the fetal villi of both pregnant women at high risk of MPS Ⅱ and normal pregnant women were also analyzed by gene testing and for fetal sex identification.Data were compared between groups by the independent samples t test. Results:The normal reference values of the IDS activity in fetal villi and plasma of normal pregnant women were(71.2±23.4) nmol/(mg·4 h) and (611.1±114.5) nmol/(mL·4 h), respectively.Among the 30 cases of high-risk fetal villi, the IDS activity in fetal villi of 8 affected male fetuses was (1.7±0.3) nmol/(mg·4 h), which was significantly lower than that of 11 unaffected male fetuses (83.2±6.3) nmol/(mg·4 h) and that of 9 non-carrier female fetuses (80.0±7.5) nmol/(mg·4 h) ( t=10.8, 8.8; all P<0.01). Meanwhile, the IDS activity was measured in the maternal peripheral plasma of 28 pregnant women at high risk of MPS Ⅱ.Among them, the IDS activity in 8 affected male fetuses was(225.4±20.5) nmol/(mL·4 h), which was significantly lower than that in non-affected male fetuses[(451.0±15.1) nmol/(mL·4 h)] and that in non-carrier female fetuses[(467.7±45.3)nmol/(mL·4 h)]. Eight known pathogenic mutations were found in 30 cases at high risk of MPS Ⅱ of fetal villi, and the mutation types were c. 1048A>C, c.212G>A, c.514C>T, c.257C>T, c.425C>T, and c. 998C>T.Of the 8 cases, 6 affected male fetuses had significantly reduced IDS activities, and the other 2 female carriers had normal IDS enzyme activities. Conclusions:The IDS activity in fetal villi and peripheral plasma of pregnant woman is consistent with the gene analysis results.The IDS activity has an important reference value for the prenatal diagnosis of MPS Ⅱ in the first trimester.When no genetic mutations are found in the probands or the pathogenicity of the new mutation remains unclear, the IDS activity in fetal villi can be detected separately for the prenatal diagnosis of MPS Ⅱ.

Phenotypic and Molecular Characteristics of Children with Progressive Familial Intrahepatic Cholestasis in South China / 대한소아소화기영양학회지

Purpose@#Progressive familial intrahepatic cholestasis (PFIC) is a rare genetic autosomal recessive disease caused by mutations in ATP8B1, ABCB11 or ABCB4. Mutational analysis of these genes is a reliable approach to identify the disorder. @*Methods@#We collected and analyzed relevant data related to clinical diagnosis, biological investigation, and molecular determination in nine children carrying these gene mutations, who were from unrelated families in South China. @*Results@#Of the nine patients (five males, four females) with PFIC, one case of PFIC1, four cases of PFIC2, and four cases of PFIC3 were diagnosed. Except in patient no. 8, jaundice and severe pruritus were the major clinical signs in all forms. γ-glutamyl transpeptidase was low in patients with PFIC1/PFIC2, and remained mildly elevated in patients with PFIC3. We identified 15 different mutations, including nine novel mutations (p.R470HfsX8, p.Q794X and p.I1170T of ABCB11 gene mutations, p.G319R, p.A1047P, p.G1074R, p.T830NfsX11, p.A1047PfsX8 and p.N1048TfsX of ABCB4 gene mutations) and six known mutations (p.G446R and p.F529del of ATP8B1 gene mutations, p.A588V, p.G1004D and p.R1057X of ABCB11 gene mutations, p.P479L of ABCB4 gene mutations). The results showed that compared with other regions, these three types of PFIC genes had different mutational spectrum in China. @*Conclusion@#The study expands the genotypic spectrum of PFIC. We identified nine novel mutations of PFIC and our findings could help in the diagnosis and treatment of this disease.

Analysis of thyroid stimulating hormone receptor gene mutation in children with hyperthyroidism / 中华内分泌代谢杂志

Objective To explore the characterization of thyroid stimulating hormone receptor(TSHR) gene mutational spectrum in children with hyperthyroidism from Guangzhou. Methods Ninety children were diagnosed with hyperthyroidism from July 2009 to July 2014 in our institute. Their median age at diagnosis was(7.5± 3.4) years, and there were 28 males and 62 females. Mutational analysis were performed by performing polymerase chain reaction (PCR) and DNA direct sequencing of exon 10 of TSHR gene. TSHR gene mutations from 50 unrelated healthy children were served as controls. The correlation between TSHR gene and hyperthyroidism in children was explored. Results A total of 3 mutations were identified in ninety children who were diagnosed with hyperthyroidism, one synonymous mutations(p.V614V), and two missense mutations( p. R707W and p. D727E). Mutation of p. V614V do not change amino acid and do not influence the structure and function of TSHR, no pathogenicity. p.R707W is a SNP associated with human cancers. The frequency of C allele of the D727E in children with hyperthyroidism was 86.7%, while 55.0% in the controls, significant different between the children with hyperthyroidism and the controls( P＜0. 01). In this study, a very high association between the D727E SNP and hyperthyroidism ( OR=18. 86, P＜0. 01) was found. Conclusion Three different mutations of TSHR gene exon 10 were identified in 90 children with hyperthyroidism, (c.1842A＞G,p.V614V、c.2119C＞T,p.R707W、c.2181G＞C,p.D727E), there were association between p.D727E and hyperthyroidism, nor p. V614V and p. R707W. Finally, p. D727E may be correlated with hyperthyroidism in children.

High risk screening and disease spectrum for 24 kinds of lysosomal storage diseases / 中华实用儿科临床杂志

Objective To evaluate the sensitivity and specificity of enzyme assays,and to provide disease spectrum of lysosomal storage diseases (LSDs).Methods Three thousand three hundred and sixty-four high risk individuals were screened for 24 LSDs at Guangzhou Women and Children's Medical Center between January 2009 and December 2016.Twenty-two kinds of enzyme activities from peripheral blood leucocytes or plasma were measured by using the fluorometry or colorimetry of corresponding artificial substrates,screening for 24 LSDs diseases.Measurement data were represented by (x) ± s,and count data were expressed as a percentage or composition ratio.Results A total of 283 subjects were diagnosed with 18 different kinds of LSDs,and the positive rate of high-risk screening was 8.4％.Among the identified patients,172 cases (60.8％) were mucopolysaccharidosis (MPS),79 cases (27.9％) were sphingolipidoses,18 cases (6.4％) were Pompe diseases,10 cases (3.5％) were affected with mucolipidoses,3 cases (1.1％) were glycoprotein storage diseases,and 1 case(0.4％) was Wolman disease.Of the MPS cases,there were 75 cases of MPS Ⅱ (43.6％),45 cases of MP5 ⅣA (26.2％),24 cases of MPS Ⅵ (14.0％) and 20 cases of MPS Ⅰ (11.6％).Gaucher disease (23/79 cases,29.1％) and metachromatic leukodystrophy (MLD) (21/79 cases,26.6％) were common in sphingolipidoses group.Both the sensitivity and specificity of enzyme assays on peripheral blood leucocytes for LSDs were 100％.Conclusions The most common kinds of LSDs are MPS Ⅱ,MPS Ⅳ A,MPS Ⅵ,Gaucher disease,MLD and Pompe disease.Leukocyte enzymology analysis of high-risk screening LSDs has high sensitivity and specificity.

Clinical and molecular analysis of two Chinese siblings with Cockayne syndrome / 中华儿科杂志

<p><b>OBJECTIVE</b>Cockayne syndrome is a rare disease and difficult to be recognized. This study aimed to expand the knowledge of the clinical and molecular characteristics of the children with Cockayne syndrome (CS).</p><p><b>METHOD</b>Clinical data of two siblings with classic CS of Guangzhou Women and Children's Medical Center from July 2013 to November 2014 were obtained and analyzed. The whole DNA of peripheral blood was collected from two CS siblings and their parents. Amplification of all exons and adjacent introns for ERCC6 gene was conducted using PCR, and measurement of reaction product was performed to find mutation sites by two-way sequencing.</p><p><b>RESULT</b>Two affected siblings were males, and came from unconsanguineous parents, 7 years and 5 months old and 4 years and 8 months old, respectively. They were in treatment because of developmental and mental retardation for years. When they were younger than one year of age, their heights and weight were within normal limits. However, poor growth of height and weight and psychomotor retardation appeared after one and a half years of age, as well as skin and eye sensitivity to sunshine, hearing impairment, optic nerve atrophy, microcephaly, and deep-set eyes. The proband's height was 90.8 cm, and weight 9.1 kg, head circumference 41 cm, and chest circumference 44 cm when he was taken to hospital. The elder brother of the proband had a height of 92 cm, weight 11.2 kg, head circumference 41 cm, and chest circumference 44 cm when he was taken to hospital. When the proband was four and a half years old, ventricular enlargement, hypomyelination, and brain atrophy were detected for his elder brother at 7 years of age by cranial MRI. MRS imaging indicated that damages occurred at the left and right sides of dorsal thalamus, lobus insularis, along with the left half circle of central neurons. Symmetrical calcification on bilateral basal ganglia was found on the brain CT scan. Pathogenic compound heterozygous c. 1357C > T (p.Arg453Ter) and c. 1607T > G (p.Leu536Trp) mutations of ERCC6 gene were identified in the two siblings which were separately inherited from their unaffected parents.</p><p><b>CONCLUSION</b>CS children are usually normal at birth, however, they have severe clinical characteristics such as poor growth, psychomotor retardation, cerebral injury, microcephalus, deep-set eyes, and skin sensitivity to sunshine. ERCC6 gene mutation usually occurs, and it is easy to misdiagnose CS as cerebral palsy, primary microcephaly, and so on.</p>

Kniest dysplasia due to mutation of COL2A1 gene / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To detect potential mutation of COL2A1 gene in two children suspected for Kniest dysplasia.</p><p><b>METHODS</b>The 54 exons and splicing regions of the COL2A1 gene were amplified with PCR and the product was subjected to direct sequencing.</p><p><b>RESULTS</b>A missense mutation (c.905C>T, p.Ala302Val) was found in the coding region of the COL2A1 gene, which has been previously reported in abroad. The patients appeared to have short trunk dwarfism, enlarged joints and midface hypoplasia.</p><p><b>CONCLUSION</b>The probands are the first cases of Kniest dysplasia described in China, and so was the p.Ala302Val mutation.</p>

Analysis of clinical features and arylsulfatase B gene mutation in thirteen Chinese children with mucopolysaccharidosis type VI / 中华儿科杂志

<p><b>OBJECTIVE</b>Mucopolysaccharidosis type VI (MPS VI) or Maroteaux-Lamy syndrome is an autosomal recessive lysosomal storage disease caused by a deficiency of arylsulfatase B(ARSB), which is required in the degradation of dermatan sulfate and chondroitin sulfate. The deficiency of ARSB leads to an accumulation of dermatan sulfate and chondroitin sulfate in lysosomes and gross excretion in the urine.Few articles about clinical study and ARSB gene mutation analysis of Chinese MPS VI patients were published. This study aimed to explore the clinical features and characteristics of ARSB gene in Chinese children with MPS VI.</p><p><b>METHOD</b>Thirteen children were diagnosed as MPS VI by ARSB enzyme activity determination during the period from 2009 to 2013. Their clinical features, radiological findings and urine glycosaminoglycan (GAG) levels were retrospectively reviewed. Direct sequencing was used to identify any mutation in the ARSB gene.</p><p><b>RESULT</b>Thirteen children were diagnosed at the average age of (3.9 ± 2.2) years with 6 male and 7 female. All of these children presented with severe form and onset at an early age of (1.5 ± 0.8) years.Other clinical features included coarse facies, short stature, skeleton deformity, corneal clouding, hepatosplenomegaly with normal intelligence. The radiological findings in all children were characteristic of dysostosis multiplex, like abnormal development of vertebral bodies of the spine, campylorrhachia and paddle-shaped widened ribs. The MRI in case 2 showed cervical cord compression and multiple cysts degeneration in the corona radiate, cella lateralis and callosum.High urine GAG levels were detected, (307.10 ± 112.14) mg/L (Normally below 70 mg/L) and (722.28 ± 245.68) µg/mg creatinine. The ARSB enzyme activity in leukocytes was low, (13.29 ± 6.22) nmol/(mg×h) [Normal range (47-169) nmol/(mg×h)] by fluorogenic assay and (0.24 ± 0.18) U/g [Normal range (1.01-11.47) U/g] by colorimetric assay. A total of 11 mutations were identified by molecular analysis, including seven previously reported mutations (p.L72R, p.G167R, p.G303E, p.F399L, p. T442M, p.Y255X and p.R327X) and four novel mutations (p.Y175D, p.S403X, p.S464X and large deletion including ex. 2, 3). The c.1197C>G (p.F399L) mutation was the most common mutation in this study (31%).</p><p><b>CONCLUSION</b>The severe form of MPS VI is characterized by early onset and rapid illness progression. Both the radiological findings and increased urine GAG are important clues to diagnose MPS VI.Large decrease or absence of ARSB activity is diagnostic for MPS VI.Four novel mutations of ARSB gene were identified. The reported mutation c.1197C>G (p.F399L) was the hot-spot mutation in this study.</p>

Clinical features of pyruvate dehydrogenase complex deficiency and gene testing in one case / 中华儿科杂志

<p><b>OBJECTIVE</b>To analyze the clinical characteristics and genetype of one children who had been diagnosed with pyruvate dehydrogenase complex deficiency.</p><p><b>METHOD</b>Comprehensive analyses of this case were performed, including clinical symptoms, signs, biochemical examinations and therapeutic effects. The eleven exons and splicing areas of PDHA1 were amplified with genomic DNA from whole blood. And variations were investigated by sequencing the PCR product. The patient was diagnosed with pyruvate dehydrogenase complex deficiency by sequence analysis of PDHA1 gene.</p><p><b>RESULT</b>The patient was a 2 years and 4 monthes old boy. He presented with muscle hypotonia and weakness for one year, and experienced recurrent episodes of unstable head control, unable to sit by himself or stand without support, with persistently hyperlactacidemia. Metabolic testing revealed blood lactate 5.37 mmol/L, pyruvate 0.44 mmol/L, and lactate/pyruvate ratio was 12.23. MRI of the brain showed hyperintense signals on the T2 and T2 Flair weighted images in the basal ganglia bilaterally. Sequence analysis of PDHA1 gene showed a G>A point mutation at nucleotide 778, resulting in a substitution of glutarnine for arginine at position 263 (R263Q). And the diagnosis of pyruvate dehydrogenase complex deficiency was identified. By giving the therapy with ketogenic diet, vitamin B(1), coenzyme Q(10) and L-carnitine , the boy was in a stable condition.</p><p><b>CONCLUSION</b>The severity and the clinical phenotypes of pyruvate dehydrogenase complex deficiency varied. Sequence analysis of PDHA1 gene revealed a 788G>A (R263Q) mutation. Patients who presented with unexplained muscle hypotonia, weakness and hyperlactacidemia could be diveded by gene analysis. And appropriate treatment can improve the quality of life.</p>

Maturity-onset diabetes of the young 2 with a novel mutation of glucokinase gene in a Chinese boy and the clinical follow-up / 中华儿科杂志

<p><b>OBJECTIVE</b>To explore the clinical and gene mutation characteristics of a child with maturity-onset diabetes of the young 2 (MODY2).</p><p><b>METHOD</b>The clinical and follow-up data of 1 patient with MODY2 were reviewed. GCK mutational analysis was performed by PCR and direct sequencing in the proband and his family members.</p><p><b>RESULT</b>The 9 years and 6 months old boy was referred to our department for short stature and mild hyperglycemia. His fasting blood glucose was elevated to 7.4-7.8 mmol/L, hemoglobin A1C 6.7%. His height was 122 cm (-2 s), weight 25 kg (-1 s), body mass index (BMI) 16.8 kg/m(2). His physical exam was unremarkable without dysmorphic features or acanthosis nigricans. The oral glucose tolerance test (OGTT) showed fasting glucose 8.17 mmol/L, insulin <2.0 mU/L, 2 h glucose 8.69 mmol/L, insulin 5.06 mU /L. The boy was treated with insulin injection for half a year. His fasting blood glucose was stable at 5.6-8.5 mmol/L, hemoglobin A1C 6.7%-6.8%. His mother's fasting blood glucose was 6.86 mmol/L, OGTT 2 h blood glucose 10.36 mmol/L, hemoglobin A1C 6.8%. GCK sequence revealed a novel GCK mutation c.34_44+15del26 in the proband and his mother, which was co-segregated with diabetes. The boy's treatment was shifted from insulin injection to diet and exercise after the diagnosis of MODY2 was confirmed. Being followed up for 2 and a half years, his fasting blood glucose was stable at 4.6-8.0 mmol/L and hemoglobin A1C 6.8%-7.1%.</p><p><b>CONCLUSION</b>The clinical features of MODY2 are persistent and stable fasting hyperglycemia over a period of months or years and small blood glucose increment (less than 3 mmol/L) after an OGTT (2 h glucose-fasting glucose). We identified a novel c.34_44+15del26 mutation in GCK which co-segregated with diabetes phenotype in this family.</p>

Clinical analysis and long-term follow-up of multiple carboxylase deficiency in 15 children / 中华实用儿科临床杂志

Objective Multiple carboxylase deficiency(MCD) is an autosomal recessively inherited defect of organic acid metabolism.The underlying mechanism is biotinidase(BT) or holocarboxylase synthetase(HLCS) deficiency.The authors reported 15 cases of MCD(clinical characteristics,diagnosis and treatment) and outcomes of long-term follow-up.Methods The clinical data of 15 patients with MCD admitted to Guangzhou Women and Children's Medical Center between Aug.2001 and Feb.2013 were analyzed.The diagnosis was confirmed by urinary organic acid analysis with gas chromatography/mass spectrometry (GC/MS),blood enzymatic determination and gene analysis.The patients consisted of 12 male and 3 female.The onset age ranged from newborn infants to 16 months.Results 1.Remarkable elevations of urinary lactate,3-oxy-butyric acid,3-OH-isovalerate,methylcitrate,3-methylcrontonylglycine,3-OH-propionate were detected in all of 15 cases.Fourteen cases with HLCS deficiency and 1 case with BT deficiency were confirmed by gene analysis.2.Most of patients with HLCS deficiency presented in the neonatal period or early infancy.The main clinical manifestations were skin rash (14 cases),tachypnea (9 cases),developmental retardation (8 cases),vomiting(5 cases),poor feeding (3 cases),developmental regradation (1 case),convulsion (1 case).Laboratory evaluation showed persistent metabolic acidosis and varied degree of ketosis,lactic acidosis,hyperuricacidemia,ammoniemia and hypoglycemia.Biotin was given to 13 patients in 10 mg/d and their metabolic disorders were corrected within 48 h,except one who gave up treatment and died.Treatment with Biotin in 5 mg/d provided clinical stability and normal neurodevelopmental outcome on follow-up for 3-11 (6.47 ± 2.70) years.3.One patient with BT deficiency presented with severe neurological symptoms(impaired consciousness,limbs trembling,tachypnea with irregular respiratory rhythm) at 16 months old.Demyelination of corpus callosum was evident on magnetic resonance imaging.Biotin treatment was given to him on the second of onset,and 1-year follow-up indicated significant improvement of his clinical symptoms,but the right limb weakness did not completely recover.Conclusions The main clinical features of HLCS deficiency include frequent skin rash,tachypnea,and metabolic disorders.BT deficiency may produce variable neurologic manifestations including demyelination of corpus callosum.Urinary organic acid analysis with GC/MS is critical to the early diagnosis of MCD.Prompt biotin treatment is recommended to correct metabolic derangements and continued therapy is essential to the improvement of long-term prognosis.Delayed commencement of therapy in BT deficiency can result in irreversible neurological damage.

Construction of the recombinant human adenovirus type 3 expressing Norovirus capsid protein gene / 中华微生物学和免疫学杂志

Objective To prepare recombinant human adenovirus type 3 expressing Norovirus cap-sid protein gene(Noro-orf2). Methods The cDNA for Noro-orf2 was amplifed by RT-PCR from stool of in-fantile gastroenteritis and cloned into the adenovirus shuttle vector pBSE3CMV-egfp. The vector pBSE3CMV-Nor was linearized with EeoR Ⅴ and Not Ⅰ, and transformed into E. coil BJ5183 with lined edenovirus ge-nomic DNA pLasmid pBRAdv3 by Rsr Ⅱ. The identification of recombinant adenovirus plasmid pBRAdv3E3dNor was performed by PCR, enzyme digestion and DNA sequencing. Then pBRAdv3E3dNor was digested with AsiS Ⅰ and transfeeted into Hep-2 cells with LipofectAMINETM 2000 to package recombi-nant adenovirus particles. Results Noro-orf2 was successfully inserted into the shuttle vector. The recombi-nant adenoviral plasmid pBRAdv3E3dNor was generated by homologous recombination in E. coil BJ5183 and confirmed by PCR and enzyme digestion. The recombinant adenovirus was successfully packaged and puri-fied. Norovirus eapsid protein gene expression was confirmed in Hep-2 cells by immunecytochemistry assay. Conclusion The recombinant type 3 adenovirus expressing Norovirus eapsid protein gene was successfully constructed. This study laid a foundation for developing vaccine against Norovirus.