Detection of Novel BEST1 Variations in Autosomal Recessive Bestrophinopathy Using Third-generation Sequencing

Objective:Autosomal recessive bestrophinopathy(ARB),a retinal degenerative disease,is characterized by central visual loss,yellowish multifocal diffuse subretinal deposits,and a dramatic decrease in the light peak on electrooculogram.The potential pathogenic mechanism involves mutations in the BEST1 gene,which encodes Ca2+-activated Cl−channels in the retinal pigment epithelium(RPE),resulting in degeneration of RPE and photoreceptor.In this study,the complete clinical characteristics of two Chinese ARB families were summarized.Methods:Pacific Biosciences(PacBio)single-molecule real-time(SMRT)sequencing was performed on the probands to screen for disease-causing gene mutations,and Sanger sequencing was applied to validate variants in the patients and their family members.Results:Two novel mutations,c.202T>C(chr11:61722628,p.Y68H)and c.867+97G>A,in the BEST1 gene were identified in the two Chinese ARB families.The novel missense mutation BEST1 c.202T>C(p.Y68H)resulted in the substitution of tyrosine with histidine in the N-terminal region of transmembrane domain 2 of bestrophin-1.Another novel variant,BEST1 c.867+97G>A(chr11:61725867),located in intron 7,might be considered a regulatory variant that changes allele-specific binding affinity based on motifs of important transcriptional regulators.Conclusion:Our findings represent the first use of third-generation sequencing(TGS)to identify novel BEST1 mutations in patients with ARB,indicating that TGS can be a more accurate and efficient tool for identifying mutations in specific genes.The novel variants identified further broaden the mutation spectrum of BEST1 in the Chinese population.

Safety and efficacy of transcatheter arterial embolization in autosomal dominant polycystic kidney patients with gross hematuria: Six case reports

BACKGROUND To retrospectively report the safety and efficacy of renal transcatheter arterial embolization for treating autosomal dominant polycystic kidney disease(ADPKD)patients with gross hematuria.CASE SUMMARY The purpose of this study is to retrospectively report the safety and efficacy of renal transcatheter arterial embolization for treating ADPKD patients with gross hematuria.Materials and methods:During the period from January 2018 to December 2019,renal transcatheter arterial embolization was carried out on 6 patients with polycystic kidneys and gross hematuria.Renal arteriography was performed first,and then we determined the location of the hemorrhage and performed embolization under digital subtraction angiography monitoring.Improvements in routine blood test results,routine urine test results,urine color and postoperative reactions were observed and analyzed.Results:Renal transcatheter arterial embolization was successfully conducted in 6 patients.The indices of 5 patients and the color of gross hematuria improved after surgery compared with before surgery.No severe complication reactions occurred.CONCLUSION For autosomal dominant polycystic kidney syndrome patients with gross hematuria,transcatheter arterial embolization was safe and effective.

Incidental renal cell carcinoma post bilateral nephrectomy in autosomal dominant polycystic kidney disease

BACKGROUND Renal cell carcinoma(RCC)is more common in patients with autosomal dominant polycystic kidney disease(ADPKD)than in the general population.Diagnosing RCC in ADPKD is challenging due to the presence of multiple renal cysts,often leading to delays and difficulties in distinguishing RCC from cyst infection or hemorrhage.A total of 38 kidneys were excised from 19 patients,with a mean age of 56.8 years and an average hemodialysis duration of 84.2 months.Eight patients underwent open nephrectomies,and 11 underwent hand-assisted laparoscopic nephrec-tomies.RCC was detected in 15.8%of kidneys,affecting 21.1%of patients.Two patients had multifocal RCC in both kidneys.All RCC cases were pT1 stage,with the largest lesion averaging 16.5 mm in diameter.The average operative duration was 120 minutes,with intraoperative blood loss averaging 184.2 mL.Five patients required blood transfusions.Postoperative complications occurred in five patients,with a mean hospital stay of 17.1 days.The mean follow-up period was 28.1 months.CONCLUSION The prevalence of RCC is higher in patients with ADPKD with ESRD than in those with ESRD alone.Thus,clinicians should be cautious and implement surveillance programs to monitor the development of RCC in patients with ADPKD,particularly those on dialysis.

Tesevatinib ameliorates progression of polycystic kidney disease in rodent models of autosomal recessive polycystic kidney disease

AIMTo investigate the therapeutic potential of tesevatinib （TSV）, a unique multi-kinase inhibitor currently in Phase Ⅱ clinical trials for autosomal dominant polycystic kidney disease （ADPKD）, in well-defined rodent models of autosomal recessive polycystic kidney disease （ARPKD）. METHODSWe administered TSV in daily doses of 7.5 and 15 mg/kg per day by I.P. to the well characterized bpk model of polycystic kidney disease starting at postnatal day（PN） 4 through PN21 to assess efficacy and toxicity in neonatal mice during postnatal development and still undergoing renal maturation. We administered TSV by oral gavage in the same doses to the orthologous PCK model （from PN30 to PN90） to assess effcacy and toxicity in animals where developmental processes are complete. The following parameters were assessed： Body weight, total kidney weight; kidney weight to body weight ratios; and morphometric determination of a cystic index and a measure of hepatic disease. Renal function was assessed by： Serum BUN; creatinine; and a 12 h urinary concentrating ability. Validation of reported targets including the level of angiogenesis and inhibition of angiogenesis （active VEGFR2/KDR） was assessed by Western analysis.RESULTSThis study demonstrates that： （1） in vivo pharmacological inhibition of multiple kinase cascades with TSV reduced phosphorylation of key mediators of cystogenesis： EGFR, ErbB2, c-Src and KDR; and （2） this reduction of kinase activity resulted in signifcant reduction of renal and biliary disease in both bpk and PCK models of ARPKD. The amelioration of disease by TSV was not associated with any apparent toxicity.CONCLUSIONThe data supports the hypothesis that this multi-kinase inhibitor TSV may provide an effective clinical therapy for human ARPKD.

A COMPLETE SCREEN FOR MUTATIONS OF THE RHODOPSIN GENE IN A PANEL OF CHINESE PATIENTS WITH AUTOSOMAL DOMINANT RETINITIS PIGMENTOSA

Objective To evaluate the prevalence of rhodopsin (RHO) mutations and the genotype-phenotype relationships in Chinese patients with autosomal dominant retinitis pigmentosa (ADRP) by conformation sensitive gel electrophoresis (CSGE) and direct DNA sequencing. Methods We have screened the five coding exons and splice sites of RHO gene in 27 probands who had no relativity from Chinese ADRP families and 100 normal controls to identify disease-associated mutations, using CSGE and direct DNA sequencing. Family members of some probands with disease-associated mutations were also genotyped to determine whether the RHO mutations segregated with retinitis pigmentosa (RP) in their families. Results Two RHO mutations, Pro347Leu and Pro327 (1-bp del), were identified separately in two families, thus the frequency of RHO mutations among this set of Chinese ADRP families is about 7.4% (2/27). Pro347Leu mutation was found in one ADRP proband as well as three her children who also had RP. She had relatively early onset at about 17 years. The only one child without this mutation had no symptom or sign of RP at age of 34. Pro327 (1-bp del) was identified in a late-onset ADRP patient, who appeared night blindness around 30 years old and in her fifties electroretinogram (ERG) has been flat in both scotopic and photopic phases. Family analysis showed that this mutation also existed in her younger dau-ghter and her elder sister, both of them also had RP. Three other family members were genotypically and phenotypically normal. Neither of the two mutations was detected in 100 normal controls.Conclusions The frequency of RHO mutations in Chinese patients was lower than that in Europe and North America. The phenotype of the patients with Pro347Leu corresponded to type 1 ADRP, with severe rod degeneration and some cone preservation later, while the phenotype of the patients carrying Pro327 (1-bp del) corresponded to type 2 ADRP, with a concomitant loss of rod and cone visual function. CSGE was found to be a sensitive, simple, and practical method for the screening of a large number of samples under highly reproducible conditions, and could be utilized in routine molecular diagnostic laboratories.

Acute abdomen and ascites as presenting features of autosomal dominant polycystic kidney disease

We describe a patient with sudden onset of abdominal pain and ascites,leading to the diagnosis of autosomal dominant polycystic kidney disease(ADPKD).Her presentation was consistent with acute liver cyst rupture as the cause of her acute illness.A review of literature on polycystic liver disease in patients with ADPKD and current management strategies are presented.This case alerts physicians that ADPKD could occasionally present as an acute abdomen;cyst rupture related to ADPKD may be considered in the differential diagnoses of acute abdomen.

A novel mutation in FBN1 gene in autosomal dominant Marfan syndrome and macular degeneration in a Chinese consanguineous family

AIM: To report a novel mutation in FBN1 gene in a Chinese consanguineous family with common Marfan syndrome(MFS) phenotype and an unusual bilateral macular degeneration. METHODS: Ophthalmic, cardiovascular and systemic examinations were performed, and genomic DNA extracted from all living family members. The 24-32 exon mutations of FBN1 gene were screened by Sanger Sequencing in all family members and 100 unrelated healthy Chinese individuals. RESULTS: In the four-generation family, classic MFS phenotypes were observed in all 5 patients, 2 of them had peculiar phenotype of bilateral macular degeneration. Mutation screening in FBN1 identified a heterozygous missense mutation(c.3932 A>G, p.Y1311 C) with co-segregation. This mutation was found with the MFS phenotypes in all 5 patients but not in unaffected members or unrelated controls. CONCLUSION: A Chinese consanguineous MFS family with uncommon bilateral macular degeneration and an unreported c.3932 A>G mutation in FBN1 was identified. Our finding expands the FBN1 mutation spectrum and its possible role in the pathogenesis of Marfan syndrome.

Current management of autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease （ADPKD）, the most frequent cause of genetic renal disease affecting approximately 4 to 7 million individuals worldwide and accounting for 7%-15% of patients on renal replacement therapy, is a systemic disorder mainly involving the kidney but cysts can also occur in other organs such as the liver, pancreas, arachnoid membrane and seminal vesicles. Though computed tomography and magnetic resonance imaging （MRI） were similar in evaluating 81% of cystic lesions of the kidney, MRI may depict septa, wall thickening or enhancement leading to upgrade in cyst classification that can affect management. A screening strategy for intracranial aneurysms would provide 1.0 additional year of life without neurological disability to a 20-year-old patient with ADPKD and reduce the fnancial impact on society of the disease. Current treatment strategies include reducing： cyclic adenosine monophosphate levels, cell proliferation and fluid secretion. Several randomised clinical trials （RCT） including mammalian target of rapamycin inhibitors, somatostatin analoguesand a vasopressin V2 receptor antagonist have beenperformed to study the effect of diverse drugs ongrowth of renal and hepatic cysts, and on deteriorationof renal function. Prophylactic native nephrectomy isindicated in patients with a history of cyst infection orecurrent haemorrhage or to those in whom space musbe made to implant the graft. The absence of largeRCT on various aspects of the disease and its treatmen leaves considerable uncertainty and ambiguity in many aspects of ADPKD patient care as it relates to end stage renal disease （ESRD）. The outlook of patients with ADPKD is improving and is in fact much better than that for patients in ESRD due to other causes. This review highlights the need for well-structured RCTs as a frst step towards trying newer interventions so as to develop updated clinical management guidelines.

Enhanced but hypofunctional osteoclastogenesis in an autosomal dominant osteopetrosis type II case carrying a c.1856C＞T mutation in CLCN7

Type II autosomal dominant osteopetrosis(ADO2), which is the most common form of osteopetrosis, is caused by heterozygous mutations in the chloride channel 7(CLCN7) gene. The osteopetrosis of ADO2 has been attributed to hypofunctional osteoclasts. The mechanism underlying the abnormality in osteoclast function remains largely unknown. This study was designed to investigate gene mutations and osteoclast function in a case that was clinically diagnosed as ADO2. Genomic DNA was extracted from blood samples of this patient, and the 25 exons of CLCN7 were amplified. Peripheral blood from the ADO2 subject and a healthy age- and sex-matched control was used to evaluate osteoclastogenesis, osteoclast morphology, and bone resorption. Analysis of DNA from the patient showed a germline heterozygous missense mutation,c.1856C>T(p.P619L), in exon 20 of CLCN7. A similar homozygous mutation at this site was previously reported in a patient with autosomal recessive osteopetrosis. When cultured, the peripheral blood mononuclear cells(PBMCs) from the ADO2 patient spontaneously differentiated into mature osteoclasts in vitro. The ADO2 patient’s PBMCs formed enhanced, but heterogeneous, osteoclasts in both the presence and absence of macrophage-colony stimulating factor, and nuclear factor-?B ligand. Bone resorption was reduced in the ADO2 patient’s osteoclasts, which exhibited aberrant morphology and abnormal distribution of integrin avβ3. Gene analysis found increased c-fos expression and reduced Rho A and integrin beta 3expression in ADO2 cells. In conclusion, our data suggest that enhanced, heterogeneous osteoclast induction may be an intrinsic characteristic of ADO2.

The Clinical Association of Autosomal Dominant Polycystic Kidney Disease and renal cell Carcinoma

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is not currently considered to be a risk factor for renal cell carcinoma (RCC). We present data from our institution demonstrating incidence of RCC with ADPKD above the incidence rate for RCC in the general population, as well as that in patients with end-stage renal disease (ESRD). The discussion relates our findings in the context of the current literature including recent case reports published in this entity.

Unique interstitial miRNA signature drives fibrosis in a murine model of autosomal dominant polycystic kidney disease

AIM To delineate changes in miRNA expression localized to the peri-cystic local microenvironment(PLM) in an orthologous mouse model of autosomal dominant polycystic kidney disease(ADPKD)(mcwPkd1^(nl/nl)).METHODS We profiled miRNA expression in the whole kidney and laser captured microdissection(LCM) samples from PLM in mcwPkd1^(nl/nl)kidneys with Qiagen miScript 384 HC miRNA PCR arrays. The three times points used are:(1) post-natal(PN) day 21, before the development of trichrome-positive areas;(2) PN28, the earliest sign of trichrome staining; and(3) PN42 following the development of progressive fibrosis. PN21 served as appropriate controls and as the reference time point for comparison of miRNA expression profiles.RESULTS LCM samples revealed three temporally upregulated miRNAs [2 to 2.75-fold at PN28 and 2.5 to 4-fold(P ≤ 0.05) at PN42] and four temporally downregulated miRNAs [2 to 2.75 fold at PN28 and 2.75 to 5-fold(P ≤ 0.05) at PN42]. Expression of twenty-six miRNAs showed no change until PN42 [six decreased(2.25 to 3.5-fold)(P ≤ 0.05) and 20 increased(2 to 4-fold)(P ≤ 0.05)]. Many critical miRNA changes seen in the LCM samples from PLM were not seen in the contralateral whole kidney.CONCLUSION Precise sampling with LCM identifies miRNA changes that occur with the initiation and progression of renal interstitial fibrosis(RIF). Identification of the target proteins regulated by these miRNAs will provide new insight into the process of fibrosis and identify unique therapeutic targets to prevent or slow the development and progression of RIF in ADPKD.

A Novel HSF4 Mutation in a Chinese Family with Autosomal Dominant Congenital Cataract

This study was aimed to identify the mutation of the whole coding region of shock transcription factor 4（HSF4） gene in a Chinese family with autosomal dominant congenital cataract（ADCC）. All exons of HSF4 were amplified by PCR. Sequence analysis of PCR products was performed. Restriction fragment length polymorphism（RFLP） analysis was conducted to confirm the pathogenic mutation. The results showed that a C to T substitution occurred at nucleotide 331 in patients of this family, leading to the replacement of the amino acid arginine-111 with cysteine in exon 3. RFLP analysis showed that the amino acid change was co-segregated with all affected individuals. It was concluded that the new mutation of c.331C〉T in HSF4 DNA may be responsible for the autosomal dominant congenital cataract in this family.

Simultaneous kidney transplantation and ipsilateral native nephrectomy in patients with autosomal dominant polycystic kidney disease

The simultaneous kidney transplantation and ipsilateral native nephrectomy for autosomal dominant polycystic kidney disease does not seem to be associated with increased rates of comorbidity and complications.This outcome can efficiently be achieved when the indication and surgical approach of native nephrectomy are properly justified.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy in a Chinese pedigree A case report using brain magnetic resonance imaging and biospy

The present study enrolled a Chinese family that comprised 34 members and spanned three generations. Eight members were diagnosed with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, and disease diagnoses corresponded with autosomal incomplete dominance inheritance. The primary clinical manifestations included paralysis, dysarthria, and mild cognitive deficits. Magnetic resonance imaging revealed diffuse leukoencephalopathy with involvement of bilateral anterior temporal lobes, in particular the pons. In addition, multiple cerebral infarction was identified in the proband. Sural nerve biopsy findings of the proband revealed granular osmophilic material deposits in the extracellular matrix, which were adjacent to smooth muscle cells of dermal arterioles. Screening exons 2-4 for NOTCH 3 mutations by direct sequencing did not reveal any abnormalities.

Re-evaluating data quality of dog mitochondrial,Y chromosomal,and autosomal SNPs genotyped by SNP array

Quality deficiencies in single nucleotide polymorphism （SNP） analyses have important implications. We used missingness rates to investigate the quality of a recently published dataset containing 424 mitochonddal, 211 Y chromosomal, and 160 432 autosomal SNPs generated by a semicustom Illumina SNP array from 5 392 dogs and 14 grey wolves. Overall, the individual missingness rate for mitochondrial SNPs was -43.8%, with 980 （18.1%）individuals completely missing mitochondrial SNP genotyping （missingness rate=l）. In males, the genotype missingness rate was -28.8% for Y chromosomal SNPs, with 374 males recording rates above 0.96. These 374 males also exhibited completely failed mitochondrial SNPs genotyping, indicative of a batch effect. Individual missingness rates for autosomal markers were greater than zero, but less than 0.5. Neither mitochondrial nor Y chromosomal SNPs achieved complete genotyping （locus missingness rate=0）, whereas 5.9% of autosomal SNPs had a locus missingness rate=l. The high missingness rates and possible batch effect show that caution and rigorous measures are vital when genotyping and analyzing SNP array data for domestic animals. Further improvements of these arrays will be helpful to future studies.

A novel CRX mutation by whole-exome sequencing in an autosomal dominant cone-rod dystrophy pedigree

AIMTo identify the disease-causing gene mutation in a Chinese pedigree with autosomal dominant cone-rod dystrophy (adCORD).METHODSA southern Chinese adCORD pedigree including 9 affected individuals was studied. Whole-exome sequencing (WES), coupling the Agilent whole-exome capture system to the Illumina HiSeq 2000 DNA sequencing platform was used to search the specific gene mutation in 3 affected family members and 1 unaffected member. After a suggested variant was found through the data analysis, the putative mutation was validated by Sanger DNA sequencing of samples from all available family members.RESULTSThe results of both WES and Sanger sequencing revealed a novel nonsense mutation c.C766T (p.Q256X) within exon 5 of CRX gene which was pathogenic for adCORD in this family. The mutation could affect photoreceptor-specific gene expression with a dominant-negative effect and resulted in loss of the OTX tail, thus the mutant protein occupies the CRX-binding site in target promoters without establishing an interaction and, consequently, may block transactivation.CONCLUSIONAll modes of Mendelian inheritance in CORD have been observed, and genetic heterogeneity is a hallmark of CORD. Therefore, conventional genetic diagnosis of CORD would be time-consuming and labor-intensive. Our study indicated the robustness and cost-effectiveness of WES in the genetic diagnosis of CORD.

A Presumed Synonymous Mutation of PKD2 Caused Autosomal Dominant Polycystic Kidney Disease in a Chinese Family

Objective:Autosomal dominant polycystic kidney disease(ADPKD)is mainly caused by the pathogenic mutation of PKD1 or PKD2 gene and usually affects bilateral kidneys.Synonymous mutations are generally assumed to be neutral as they do not alter amino acids.Herein,we described an extremely rare ADPKD child caused by a heterozygous synonymous mutation of PKD2 gene accompanied by massive proteinuria and congenital solitary kidney.Methods:Clinical characteristics of the patients were summarized.Whole-exome sequencing was performed to screen the disease-causing gene mutation,and reverse transcription polymerase chain reaction(RT-PCR)and Sanger sequencing were applied to analyze the impact of the identified mutation on gene transcription and splicing.Results:Polycystic changes were found in the solitary kidney of a girl initially presented with nephrotic-range proteinuria.Thereafter her mother and 2 other family members were diagnosed to be ADPKD.Whole-exome sequencing of the proband identified a heterozygous synonymous mutation(c.1716G>A,p.Lys572=)located in the splicing site of exon 7 in PKD2 gene,which was co-segregated with the PKD phenotype in the family.RT-PCR and direct sequencing of amplified products revealed that this heterozygous synonymous mutation led to exon7 skipping in PKD2 gene.Conclusion:We reported an extremely rare child case of ADPKD2 in combination with solitary kidney and nephrotic-range proteinuria,and firstly confirmed the pathogenicity of a heterozygous synonymous mutation(c.1716G>A)in PKD2 gene.The results indicate that synonymous mutations should not be excluded from disease-causing if they are located in splicing site of an exon.

Successful endoscopic surgery for emphysematous pyelonephritis in a non-diabetic patient with autosomal dominant polycystic kidney disease: A case report

BACKGROUND Emphysema pyelonephritis(EPN)is a very dangerous type of urinary tract infection.It is a lethal disease that develops rapidly and causes the patient to deteriorate rapidly,and it can easily lead to systemic infections and even sepsis.The incidence is extremely low,and it is prevalent in patients with diabetes.We here report a case of EPN in a non-diabetic patient with autosomal dominant polycystic kidney disease(ADPKD).We share the diagnosis and treatment procedure for this extremely rare condition to make this disease easier to identify and address early.CASE SUMMARY A 47-year-old woman presented to the emergency department of our hospital with a high fever and left back pain lasting 4 d.She had a history of autosomal dominant polycystic kidney and polycystic liver.She was diagnosed with left type I EPN and her vital signs deteriorated so quickly that she underwent an emergency operation in which a D-J tube was inserted into her left ureter on the second day after admission.Two months later,she underwent a second-stage flexible ureteroscopy and lithotripsy.Despite postoperative sepsis,she finally recovered after active symptomatic support treatment and effective anti-infective treatment.CONCLUSION Although EPN is more likely to occur in diabetic patients,for non-diabetic patients with ADPKD and upper urinary tract obstruction,the disease also causes rapid deterioration.Early and accurate diagnosis and timely removal of the obstruction by invasive means may be able to save the damaged kidney and the patient’s life.

Autosomal dominant tubulointerstitial kidney disease with a novel heterozygous missense mutation in the uromodulin gene: A case report

BACKGROUND Autosomal dominant tubulointerstitial kidney disease(ADTKD)is a progressive chronic disease that is inherited in an autosomal dominant fashion.Symptoms include hyperuricemia,gout,interstitial nephritis,renal cysts,and progressive renal damage that can lead to end-stage renal disease.Mutations in the uromodulin gene(UMOD)characterize the ADTKD-UMOD clinical subtype of this disease.To date,>100 UMOD mutations have been identified.Early diagnosis of ADTKD-UMOD is important to treat the disease,slow down disease progression,and facilitate the identification of potentially affected family members.CASE SUMMARY We report a 40-year-old man harboring a novel heterozygous missense mutation in UMOD(c.554G>T;p.Arg185Leu).The patient had hyperuricemia,gout,and chronic kidney disease.The same mutation was detected in his daughter,aunt and cousin.CONCLUSION A single nucleotide substitution in exon 3 of UMOD was responsible for the heterozygous missense mutation(c.554G>T,p.Arg185Leu).

Novel Pathogenic Mutation of PNPLA1 Identified in Autosomal Recessive Congenital Ichthyosis:A Case Report

Autosomal recessive congenital ichthyosis(ARCI)is characterized by being born as collodion babies,hyperkeratosis,and skin scaling.We described a collodion baby at birth with mild ectropion,eclabium,and syndactyly.Whole exome sequencing showed a compound heterozygous variant c.[56C>A],p.(Ser19X)and c.[100G>A],p.(Ala34Thr)in the PNPLA1 gene[NM_001145717;exon 1].The protein encoded by PNPLA1 acts as a unique transacylase that specifically transfers linoleic acid from triglyceride toω-hydroxy fatty acid in ceramide,thus giving rise toω-O-acylceramide,a particular class of sphingolipids that is essential for skin barrier function.The variant was located in the patatin core domain of PNPLA1 and resulted in a truncated protein which could disrupt the function of the protein.This case report highlights a novel compound heterozygous mutation in PNPLA1 identified in a Chinese child.