A Case of Renal Coloboma Syndrome Caused by Spontaneous Mutation of PAX2 / 罕见病研究

This article reports a case of a child with full-length (paired box family, PAX) PAX2 mutation leading to renal coloboma syndrome. The patient is an 11-year-old boy presented with persistent foamy urine and unexplained renal failure. The boy has suffered from vision decline ever since infancy. Genetic testing confirms the mutation of the PAX2 splice site (c.862-1G > A). Sanger sequencing shows no mutation at this site in his parents and demonstrates a spontaneous mutation. His clinical manifestations also confirms diagnosis of renal coloboma syndrome. The PAX2 mutation was responsible for the boy's progression to end-stage renal disease and extrarenal manifestations.

Report of papillorenal syndrome in a family and literature review / 中华肾脏病杂志

Objective To investigate the clinical manifestations and genetic features of children with papillorenal syndrome caused by PAX2 gene mutation.Methods Clinical manifestations,imaging changes and sequencing data were collected and analyzed from a family with papillorenal syndrome who were diagnosed in Wuhan Children's Hospital in February 2018."PAX2","papillorenal syndrome" and "renal coloboma syndrome" were used as key words to search in China National Knowledge Infrastructure,Wangfang Data Knowledge Service Platform,PubMed and Human Gene Mutation Database up to April 2018.Results A ten years old girl was admitted due to "edema and urine output decreased for one week".Lab showed BUN 25.30 mmol/L,Scr 766.5 μmol/L,Urine protein 3.6 g/24 h.Imaging examination showed bilateral vesical and ureter reflux combined with left duplex kidney and duplication of ureter.Developmental dysplasia of the left hip was also found.The father of the patient had been diagnosed with chronic kidney disease for 10 years and on hemodialysis for 6 years.Next generation sequencing revealed that both the father and daughter carried a heterozygous nonsense mutation in the exon3 c.219C ＞ G(p.Y73X) of PAX2.No Chinese literature ever was reported about papillorenal syndrome.Ninety-four articles in English were retrieved and 177 patients with papillorenal syndrome were confirmed by gene analysis with a total of 92 PAX2 variants.Ten nonsense mutations had been reported.Developmental dysplasia of the hip (DDH) never be reported before.Conclusion Papillorenal syndrome caused by PAX2 mutation can mainly manifest as abnormal development of both kidney and optic nerve,which may be accompanied by other systemic abnormalities,it is rarely reported in China.DDH may be a new phenotype of papillorenal syndrome.

Mutación infrecuente en el síndrome renal-coloboma: a propósito de un caso y revisión / Infrequent mutation in renal-coloboma syndrome: case report and review

El síndrome renal-coloboma es una enfermedad autosómica dominante caracterizada por hipodisplasia renal y coloboma. Se presenta el caso de una niña de 12 años afecta de enfermedad renal crónica, colobomas papilares bilaterales y mutación excepcional del gen PAX-2. Con diagnóstico prenatal de hipoplasia renal bilateral, a los 5 días de vida, presentó clínica y datos analíticos compatibles con enfermedad renal crónica. En los controles posteriores, se apreció reflujo vesicoureteral grado ii bilateral, que se resolvió espontáneamente, proteinuria mantenida en rango no nefrótico controlada con enalapril y colobomas bilaterales con atrofia macular izquierda. La función renal se mantuvo estable. El estudio genético demostró mutación p.R104X de novo sin sentido en heterocigosis. Globalmente, existen documentados 80 casos de síndrome renal-coloboma asociado a mutaciones de este gen. Las evaluaciones oftalmológicas y genéticas son fundamentales en los casos de hipodisplasia renal. La función renal determinará el pronóstico. Se realizó una revisión bibliográfica de la etiopatogenia de la enfermedad.

Renal-coloboma syndrome is an autosomal dominant disease characterized by renal hypodysplasia and coloboma. A case of a 12-year-old girl with chronic kidney disease, bilateral optic nerve colobomas and an exceptional PAX-2 gene mutation is presented. Diagnosed in prenatal scans with bilateral renal hypoplasia, she presented clinical and laboratory findings of chronic kidney disease at 5 days of life. Following tests showed grade II bilateral vesicoureteral reflux spontaneously solved, maintained non nephrotic proteinuria controlled with enalapril and bilateral colobomas with left macular atrophy. Renal function remained stable. Genetic study showed de novo and non sense mutation p.R104X in heterocygosis. Currently there are 80 published cases of renal-coloboma syndrome associated with this gene mutations. Ophthalmologic and genetic evaluations are crucial in cases affected by renal hypodysplasia. Renal function will establish prognosis. We review the etiopathogenesis of this disease.

Papillorenal syndrome and the PAX2 gene / 国际儿科学杂志

Papillorenal syndrome,also known as renal coloboma syndrome,is an autosomal donunant inherited condition typically featured by congenital aplasia of kidneys and eyes,most of which occur in childhood.Studies have revealed that a mutation in PAX2 gene is the critical etiology of Papillorenal Syndrome.The PAX2 gene is located at chromosome 10q23-24,encoding PAX2 protein isoform c,which belongs to the transcription factors family paired box family that regulate downstream gene expression and play an important role in development of organs such as the kidney and the eye.Mutations in PAX2 result in structural and functional abnormality of PAX2 protein isoform c,which leads to the dysplasia of the related organs.More than 80 mutations in the PAX2 gene have been currently reported,causing various clinical phenotypes.The mutational analysis of the PAX2 gene would be of help to direct the diagnosis,monitoring and treatment of papillorenal syndrome.This review summarizes the research progress of papillorenal syndrome and mutations in the PAX2 gene.

Detection and analysis of gene mutation in a case of child's renal coloboma syndrome / 中华眼底病杂志

Objective To analyze and identify the pathogenic mutation that caused a case of child's renal coloboma syndrome (RCS).Methods A child with congenital cataract in the right eye and optic disc defect in the left eye and his parents with normal phenotype were included in the study.The blood of the child and his parents were captured to extract DNA and make molecular test.The possible variants were screened through NGS sequencing using the ophthalmology gene panel on illumina NextSeq 500 platform,and proved the selected PAX2 mutation by Sanger sequencing.Pathogenicity report was retrieved through PubMed and related database.Pathogenicity analysis of the candidate mutated site has careful consideration of the patient's clinical presentations and sequencing result base on Standards and Guidelines for the Interpretation of Sequence Variants revised by ACMG.According to the results of gene diagnosis,the child was executed related clinical examinations on kidney.Results The sequence result showed that a heterozygous mutation in PAX2,c.70dupG (p.V26Gfs*28),which lead to truncated protein product that terminated after 28 amino acids of the mutated site.Both of his normal parents were not carriers of the heterozygous mutation.Sanger sequencing results of the child and his parents were consistent with the NGS sequencing.The autosomal dominant disease phenotype was inferred to be caused by the heterozygous mutation of c.70dupG (p.V26Gfs*28) of PAX2 gene.Renal color Doppler ultrasound results showed the child with small renal cysts on the left and mildly separated collecting system.Renal function tests showed the child with αl microglobulin index increased.Conclusion The heterozygous mutation c.70dupG (p.V26Gfs*28) in PAX2 is the genetic pathogenic cause for the patient with RCS.

Expression of Pax2 and E-cadherin in renal cell carcinoma: correlation with clinicopathologic parameters / 中国医师杂志

Objective To investigate the expression of paired box 2 (Pax2) and E-cadherin in human renal cell carcinoma (RCC) and their correlation with clinicopathologic parameters.Methods The RCC tissue microarrays containing 85 renal cell carcinoma specimens and 35 normal kidney tissue specimens were used to detect Pax2 and E-cadherin expressions by immunohistochemistry.Results The positive expression rate of Pax2 was 77.6％ (66/85) in RCC specimens,which was significantly higher than that in 35 normal kidney tissue specimens (P ＜ 0.01).The positive expression rate of E-cadherin was 30.6％ (26/85) in RCC specimens,which was significantly lower than that in 35 normal kidney tissue specimens (P ＜ 0.01).The expression of Pax2 in RCC was significantly related to histological classification and pathological grade (P ＜ 0.05),while it was not related to the size of tumor and clinical stage (P ＞ 0.05).The expression of E-cadherin in RCC was significantly related to the size of tumor,histological classification,pathological grade and clinical stage (P ＜ 0.05).The positive expression rate of E-cadherin in survival group was significantly higher than that in death group (P ＜ 0.05).Conclusions The abnormal expressions of Pax2 and E-cadherin may play a crucial stage in development of human RCC.Detection of the expressions of Pax2 and E-cadherin can be used in the evaluation of malignant degree and prognosis of RCC.

Comparison of paired box genes 8 and 2 expression in epithelium tissues and the related tumors / 中华肿瘤杂志

Objective@#To explore the expressional differences between paired box genes 2(Pax2) and 8 (Pax8) protein in different kinds of epitheliums and tumors, and to investigate the clinicopathologic significance.@*Methods@#Expression levels of Pax2 and Pax8 protein were detected in 75 cases of different human epithelium tissues and 255 cases of different tumors on tissue microarray by immunohistochemistry.@*Results@#Pax2 and Pax8 selectively expressed in different tissues. The positive rates of Pax8 protein expressed in the normal epithelium of the thyroid, urinary system and female reproductive system were 100% (2/2), 60.0% (3/5) and 76.9% (10/13), respectively. The positive rates of Pax2 expressed in the epithelium tissues of urinary system and the female reproductive system were 40.0% (2/5) and 38.5% (5/13) respectively. However, the expression of Pax2 protein was not detected in the normal thyroid epithelium. The positive rate of Pax8 protein expressing in the epithelium of reproductive system was significantly higher than that of Pax2 protein (P<0.05). The tumors derived from different tissues also expressed different levels of protein Pax2 and Pax8. The positive rates of Pax8 in renal cell carcinoma, thyroid carcinoma and endometrial adenocarcinoma were 65.2% (15/23), 66.7% (10/15) and 80.0% (4/5), respectively. The positive rates of Pax2 in renal cell carcinoma, thyroid carcinoma and endometrial adenocarcinoma were 34.8% (8/23), 13.3% (2/15) and 20.0% (1/5), respectively. The positive rates of Pax8 protein expressed in renal cell carcinoma, thyroid carcinoma and endometrial adenocarcinoma were significantly higher than those of Pax2 protein (P<0.05). The positive rates of Pax8 in ovarian serous carcinoma, endometrial carcinoma and clear cell carcinoma were 92.9% (26/28), 81.8% (9/11) and 82.4% (14/17), respectively. The positive rates of Pax2 in ovarian serous carcinoma, endometrial carcinoma and clear cell carcinoma were 28.6% (8/28), 9.1% (1/11) and 17.6% (3/17), respectively. The positive rates of Pax8 protein expressed in ovarian serous carcinoma, endometrial carcinoma and clear cell carcinomawere significantly higher than those of Pax2 protein (P<0.05).@*Conclusions@#Pax2 and Pax8 are specifically expressed in female reproductive system and uritany system. However, the positive expression of Pax8 is superior to that of Pax2. The combined expression of Pax8 and Pax2 can be used in the differential diagnosis of epithelial tumors derived from different origins.

Value of parotid gland carcinoma tissue PAX2 and PAX8 expression for jointly predicting recurrence and metastasis after radical surgery / 重庆医学

Objective To investigate the value of parotid gland carcinoma tissue PAX2 and PAX8 expression for combined prediction of recurrence and metastasis after radical surgery.Methods Forty-six patients with parotid gland carcinoma treated by parotid gland joint neck radical operation served as the research subjects.The immunohistochemical method was applied to detect the PAX2 and PAX8 protein expression level in surgical removal parotid gland carcinoma tissues and tissues adjacent to carcinoma.Results The PAX2 and PAX8 protein positive expression rates of parotid gland carcinoma tissue were 76.09％ and 69.57％ respectively,which were higher than 26.09 ％ and 28.26 ％ in the tissue adjacent to carcinoma (P＜0.05).The local recurrence rate in the patients with parotid gland carcinoma radical operation and 3-year follow-up was 41.30％,and lymph node metastasis rate was 34.78％.Moreover the metastasis and recurrence rate in the patients with PAX2 protein positive expressing were higher than those in the patients with PAX2 negative expression,and the metastasis and recurrence rate in the patients with PAX8 protein positive expressionwere higher than those in the patients with PAX8 negative expression (P＜0.(05).The Logistic regression analysis results showed that parotid gland carcinoma tissue PAX2 and PAX8 expression levels had close correlation with the recurrence and metastasis after radical surgery were closely correlated (P＜0.05).Parotid gland carcinoma tissue PAX2 and PAX8 expression levels for predicting the post-operative recurrence and metastasis had good value,in which the value of PAX2 positive and PAX8 positive expression for predicting the recurrence and metastasis was optimal.Conclusion Parotid gland carcinoma tissue PAX2 and PAX8 expression levels are closely correlated with the prognosis situation such as recurrence and metastasis after radical surgery,moreover their combined detection has better value for predicting the prognosis,which can serve as the reference indicator for the prognosisassessment after radical operation of parotid gland carcinoma.

Significance and expression of PAX8,PAX2,p53 and RAS in ovary and fallopian tubes to origin of ovarian high grade serous carcinoma / 中华妇产科杂志

Objective To explore the origin of ovarian high grade serous carcinoma(HGSC) through analysing the expression and significance of PAX8,PAX2,p53 and RAS in the ovary and fallopian tube of different types and grades of serous carcinoma. Methods A total of 44 cases tissue samples of ovarian tumor including 34 malignant ovarian tumor and 10 normal normal tissue (as control group) were collected from the admitted patients in Affiliated Tumor Hospital of Guangxi Medical University from January 2015 to January 2016. Fallopian tube tissues were segmented in accordance with the fimbria, ampulla, isthmus and the corresponding ovarian tissues were by the side. There were 34 cases of patients with ovarian cancer including 29 cases of epithelial ovarian cancer (27 serous carcinoma, 1 mucinous carcinoma,1 endometrioid adenocarcinoma)and 5 non-epithelial ovarian cancer(sex cord-interstitial tumor). Among 27 cases of patients with ovarian serous cancer,there were 23 HGSC and 4 low-grade ovarian serous cancer (LGSC). One hundred fifty-three cases of samples were diagnosed as ovarian serous cancer by Shandong University Affiliated Qilu Hospital from 2005 to 2013 and these samples were made tissue microarray.(1)To analyze the expression and differences of PAX8,PAX2,p53 and RAS in the above tissues and tissue microarray from ovarian and tubal of HGSC and control women by immunohistochemistry methods.(2)To compare the expression levels of PAX8,PAX2,p53 and RAS in ovarian and fallopian tubes of ovarian cancer patients with different pathological types. (3) To analyze the correlations of tubal and ovarian tissue in PAX8,PAX2,p53 and RAS expression of HGSC.(4)To analyze the factors of the prognosis of ovarian serous cancer in tissue microarray by single factor analysis method. Results (1)PAX8,PAX2, p53 and RAS expression was negative in normal ovarian epithelium of control group,but the expression of PAX8, PAX2, p53 and RAS were strongly positive brown in secrete cells of normal fallopian tube epithelium.(2)p53 and RAS expression of fallopian tube epithelium in the epithelial ovarian cancer group were significantly higher than those in the non-epithelial ovarian cancer groups(P<0.05),but the expression of PAX8 and PAX2 in fallopian tube and the expression of PAX8,PAX2,p53 and RAS in ovarian tissue was not statistically significant in the groups(P>0.05).PAX8,PAX2 and p53 expression of the ovarian in HGSC group were significantly higher than those in LGSC group(P<0.05),while the expression of RAS was lower in the ovarian of the high-grade group (P<0.05), while the expression of PAX8, PAX2, p53 and RAS in fallopian tube was not statistically significant in the groups(P>0.05).(3)There was a significantly positive correlation between fallopian tube and the corresponding ovary of HGSC in PAX8 and PAX2 expression(r=0.422, P=0.045; r=0.693, P=0.000), but not correlation in p53 and RAS expression (r=0.058, P=0.793; r=-0.190,P=0.384).(4)Univariate survival analysis showed that the progression free survival time in patients with ovarian serous cancer group was significantly correlated with the protein expression of PAX8, PAX2 and RAS(P<0.05),but there were not correlated with age,surgical staging,cell differentiation,lymph node metastasis and preoperative chemotherapy and p53 protein expression (P>0.05). The total survival time in patients with ovarian serous cancer group was significantly correlated with the protein expression of PAX8 (P<0.05),but there were not correlated with age,surgical staging,cell differentiation,lymph node metastasis and preoperative chemotherapy and the protein expression of PAX2, RAS and p53 (P>0.05). Conclusions PAX8, PAX2, p53, RAS are of great significance for the study of origin of HGSC. HGSC may be derived from fallopian tube, but further investigation would be necessary to confirm this. PAX8, PAX2, p53, RAS could be expected to be used as predictors of survival prognosis in patients with ovarian serous cancer.

Expressions of PAX-2 and PTEN in endometrial lesions and their correlation with endometrial intraepithelial neoplasia / 肿瘤研究与临床

Objective To observe the expression of PAX-2 and PTEN in different types of endometrial lesions, and to study their relationship with endometrial intraepithelial neoplasia (EIN). Methods 60 cases of endometrial hyperplasic lesions and 70 cases of endometrial carcinoma were enrolled. All cases were reclassified by using the diagnostic criteria of EIN, and PAX-2 and PTEN were stained to compare the difference among them. Results The deletion rates of PAX-2 in benign hyperplasia, EIN and endometrial carcinoma were 39.5 % (15/38), 72.7 % (16/22) and 78.6 % (55/70), respectively, and there was a statistical difference (χ2= 21.664, P= 0.000). The deletion rates of PTEN in benign hyperplasia, EIN and endometrial carcinoma were 47.4%(18/38), 54.5%(12/22) and 75.7%(53/70), respectively, and there was no statistical difference (χ2=2.878, P=0.411). Conclusion The staining of PAX-2 could be considered as a reliable adjuvant diagnostic method in the diagnostic criteria of EIN, however, the loss of PTEN just should be regarded as a suggestion of EIN, not a confirmed diagnostic basis.

The role of PAX2 in acute kidney injury and chronic kidney disease / 国际儿科学杂志

Paired box2 ( PAX2 ) is a transciption factor which mainly expressed in the developing kid-ney. Researches indicate that PAX2 promote the transcription through interactions with the adaptor PAX transac-tivation domain interacting protein(PTIP). Otherwise,PAX2 protein can lead to chromatin compaction and gene silencing through interactions with Grg4. PAX2 reexpressed in acute kidney injury and involved in promoting cell proliferation. Congenital PAX2 gene mutation is closely related to congenital abnormalies of the kidney and uri-nary tract. In chronic kidney disease,PAX2 promote proliferation and cyst formation. Here,the recent researches on the function of PAX2 and its role in acute kidney injury and chronic kidney disease are reviewed.

Study on transdifferentiation-acquiring tissue stem cell potency during renal tubular epithelial cells inflammatory damage / 国际检验医学杂志

Objective To study the potency of transdifferentiated renal tubular epithelial cells for acquiring the tissue stem cells during renal fibrosis.Methods The in vitro cellular model of renal tubular epithelial cells(NRK-52E)transdifferentiation under the inflammatory environment of the local renin-angiotensin (AngⅡ)system was established.The expression and change situation of the embryonic kidney developmental gene Pax2 and the tissue stem cell surface marker CD133 were observed.Results Local high concentration of AngⅡcould stimulate the NRK-52E cells to express Pax2 and CD133 molecule,its effect demonstrated the dose-and time-dependent relation.Conclusion The inflammatory damage leads to the transdifferentiated renal tubular epithelial cells po-tency to acquire the tissue stem cell.

Effects of intermedin pretreatment on associated repairing genes in the kidney of rats with renal ischemia-reperfusion injury / 中华肾脏病杂志

Objective To investigate the effects of intermedin (IMD) pretreatment on associated repairing genes of the rats with injured kidneys by ischemia reperfusion injury (IRI)during the repair and regeneration process.Methods A total of 144 healthy male Wistar rats were randomly divided into 4 gourps:sham opration group,IRI group,empty plasmid group (EP)and IMD group.After resection of right kidneys of the rats,plasmid was transfected into the left kidneys by using ultrasonic microbubble technology.After one week,the renal IRI models were programmed.The samples of renal tissues after 1 d,2 d,3 d,4 d,7 d and 14 d of reperfusion were harvested respectively,then the mRNA expressions of the Pax-2,ZO-1,Ncam,Wt-1 and vimentin in renal tissues were detected by RT-PCR; the protein expressions of Pax-2,Wt-1 and vimentin were analyzed by Western blotting and the protein expressions of ZO-1 and Ncam were measured by ELISIA.Results (1) Compared with the sham group,the mRNA and protein expression of Pax-2,ZO-1,Ncam,Wt-1 and vimentin of the rats in IRI group increased significantly from day 1 to day 3 (P＜0.05),which peaked at day 2.After day 4,the above expressions in IRI group returned to normal level.(2) In IMD group,the mRNA and protein expressions of Pax-2,Zo-1,Ncam,Wt-1 and vimentin were significantly higher than those in other 3 groups (P＜0.05) at the same time after IRI day 1 to day 4,with a maximum in day 2.(3) The above expressions in IRI group,EP group,IMD group had no significant differences compared with sham group after day 7 or day 14 respectively (P＞0.05),and either between IRI group and EP group,though the expressions of the genes in IRI group and EP group increased compared with sham group after day 4.(4) The above expressions between IRI group and EP group also had no significant difference (P＞0.05).(5) Changes of ZO-1 and Ncam protein expression detected by ELISA were similar to those abore mRNA and protein expression by RT-PCR and Western blotting.Conclusion IMD pretreatment plays an important role in up-regulation of the expressions of associated repair genes during the process of repair and regeneration after renal ischemia reperfusion injury.

Characterization of the antigenic phenotype of alphaB-crystallin-expressing peripapillary glial cells in the developing chick retina / 대한해부학회지

Radial glia are transdifferentiated into astrocytes within the developing brain and spinal cord. The neural retina contains Muller cells, which are retinal radial glia. Some of the cells that surround the optic nerve head among Muller cells in the chicken retina are called peripapillary glial cells (PPGCs). PPGCs express different molecules compared to typical Muller cells. However, an antigenic PPGC phenotype has not yet been clearly established. In this study, we classified the antigenic PPGC phenotypes and identified the differentiation stages of these cells. At embryonic day (E)8, alphaB-crystallin-positive PPGCs had a bipolar shape with long processes that traversed entire layers of the retina. Pax2 and vimentin were expressed in alphaB-crystallin-positive PPGCs. Glial fibrillary acidic protein (GFAP) immunoreactivity was not observed in PPGCs. At E18, alphaB-crystallin immunoreactivity disappeared from the vitread processes of PPGCs. However, the PPGC cell bodies and ventricular processes contained alphaB-crystallin protein, and the PPGCs retained the same Pax2-positive/vimentin-positive/GFAP-negative profile as that seen at E8. At post-hatch day 120, alphaB-crystallin and Pax2 immunoreactivity was not observed, but vimentin and GFAP expression was clearly observed in the presumptive location of the PPGCs. Furthermore, these two proteins overlapped within that location. Considering that vimentin expression is prolonged until the post-hatching period in chicken brain, these findings suggest that Pax2-negative/vimentin-positive/GFAP-positive PPGCs are phenotypically identical to mature astrocytes in this avian species.

PAX2 expression and its significance in kidneys / 国际儿科学杂志

PAX2 gene encodes a nuclear transcription factor and plays a pivotal role for embryonic kidney development.It is expressed during the entire developmental process of pronephron,mesonephron and metanephron,involving in the regulation of embryonic kidney development at various fetal stages,but its expression disappeared in mature nephrons.Recently,it was found that PAX2 was re-expressed in nephropathy.Gene mutation and re-expression of PAX2 are closely related with congenital and acquired renal diseases.This paper reviews the role and significance of PAX2 expression in kidney disease from the aspects of normal expression,gene mutation and abnormal expression.

PAX2 Gene Assay in a Family of Ocular Coloboma with Bilateral Renal Hypoplasia / 대한신장학회지

We report one family with bilateral renal hypoplasia and ocular coloboma in two consecutive generations. Ophthalmological examination revealed optic disc coloboma and decreased visual acuity. Fragments spanning exon 1-12 of the PAX2 gene were amplified from genomic DNA using PCR primers. The PCR products were purified and directly sequenced. No definite mutation was detected in the PAX2 genes in these patients, but two coding region single nucleotide polymorphisms were identified. This result suggests that the optic disc coloboma with bilateral renal hypoplasia might be genetically heterogenous or other genes could be responsible.

PAX2 Expression in Renal Dysplasia

BACKGROUND: Renal dysplasia is the abnormal development of the kidney. The condition is usually detected in childhood along with other urinary tract anomalies, but can remain unnoticed until adulthood. It was recently reported that a PAX2 gene mutation plays a major role in the development of renal dysplasia. The aim of this study was to examine the expression of PAX2 in dysplastic kidneys of children and adults. METHODS: A total of 30 cases diagnosed with renal dysplasia after a nephrectomy were examined. PAX2 expression was evaluated using immunohistochemistry. Apoptosis was detected using an Apop Tag detection kit. RESULTS: In the dysplastic kidneys, there was strong PAX2 expression in the epithelia of the primitive ducts in both children and adults, but the degree was significantly lower in adults (p=0.007). However, the mesenchyme surrounding the primitive ducts of children showed stronger staining for the smooth muscle actin antibody and trichrome than the adults. The apoptosis index was significantly higher in the primitive duct epithelia than in the surrounding normal collecting duct epithelia (p=0.000). CONCLUSIONS: PAX2 is overexpressed in the primitive ducts of renal dysplasia, which is sustained until adulthood and is associated with increased apoptosis. However, a decrease in PAX2 expression in the dysplastic epithelia and mesenchymal cuff of adults suggest a gradual regression of the dysplastic elements with time.