Liver disease in autosomal recessive polycystic kidney disease

Hepatic complications occur in a significant proportion of children with autosomal recessive polycystic kidney disease (ARPKD). PKHD1/fibrocystin, the defective gene in ARPKD, is expressed in the cilia of bile duct epithelium and leads to abnormalities in the rubric of the ductal plate malformation. Portal hypertension and biliary disease are the major liver problems seen in ARPKD. Complete blood counting, physical examination, ultrasonography and magnetic resonance (MR) cholangiography are indicated as screening procedures for hepatic disease in ARPKD. Medical and surgical interventions are potentially indicated for children with portal hypertension and/or biliary disease. A high index of suspicion for the diagnosis of cholangitis needs to be maintained in children with biliary disease. The implications of hepatic disease need to be considered in the decision-making regarding renal transplantation in ARPKD.     

Predominant extrahepatic biliary disease in autosomal recessive polycystic kidney disease: a new association

Autosomal recessive polycystic kidney disease (ARPKD) is characterized by dilation of ectatic renal collecting ducts, intrahepatic biliary dysgenesis, and portal fibrosis. Portal hypertension and recurrent bacterial cholangitis can dominate the clinical picture in long-term survivors. Predominant extrahepatic bile duct disease was revealed in four patients who underwent magnetic resonance cholangiopancreatography. All four patients had portal hypertension, although liver biochemistries did not suggest biliary disease. In two of the patients, cholangitis was clinically ascribed to the bile duct disease. Western blot analysis of plasma membranes from normal rat extrahepatic bile duct and kidney revealed the presence of polyductin as a single approximately 440 kDa protein. Although the exact function of polyductin in the extrahepatic duct is unknown, it may have a role in the development and control of lumenal size. Clinical management of patients with ARPKD should include consideration of potential problems related to extrahepatic bile duct disease.     

常染色体隐性遗传性多囊肾病的研究进展

常染色体隐性遗传性多囊肾病(ARPKD),发病率较低,多发于新生儿期和婴儿期,其致病基因为多囊肾/多囊肝病变1基因(PKHD1)。ARPKD的发病机制目前尚不十分清楚,治疗原则主要是控制并发症,延缓疾病的进展。文章综述近年来国内外ARPKD发病机制和治疗的新进展。     

MR cholangiography in children with autosomal recessive polycystic kidney disease

Background. Magnetic resonance cholangiography (MRC) is a relatively new, non-invasive imaging technique of the biliary tree that has shown good correlation with endoscopic retrograde cholangiopancreatography. The liver manifestation of autosomal recessive polycystic kidney disease (ARPKD) is congenital hepatic fibrosis (CHF). CHF may be accompanied by Caroli's disease, which is characterised by a non-obstructive dilation of the intrahepatic bile ducts. Objective. A prospective study was conducted to determine the presence and extent of Caroli's disease in children with ARPKD. Materials and methods. Seven children with ARPKD aged from 3.0 to 10.1 years were examined. CHF was confirmed in all biopsied cases (5 of 7). All children had been followed by repeated abdominal US examinations for many years. The MR examination included a morphological imaging study using a T2-weighted turbo spin-echo sequence and a heavily T2-weighted inversion-recovery turbo spin-echo sequence with three-dimensional maximum intensity projection (MIP) reconstructions for MRC. Results. The diagnosis of Caroli's disease could be made in one case by US; in two other children Caroli's disease was suspected, but the differentiation from hepatic cysts was not possible. By MRC, Caroli's disease could be diagnosed in three of seven children. Furthermore, MRC with MIP reconstructions demonstrated the extent of the disease by showing the entire biliary tree from different angles. Conclusions. MRC is a valuable method to establish the diagnosis and demonstrate the extent of Caroli's disease. Received: 5 January 1998 Accepted: 9 December 1998     

罕见婴儿常染色体隐性遗传性多囊肾合并扩张型心肌病2例

对2例罕见的婴儿常染色体隐性遗传性多囊肾合并扩张型心肌病的临床资料及其家系遗传特征进行回顾性分析。2例患儿均为散发,分别为6个月、3个月男婴,均因"咳嗽后发现心影大"入院,心脏彩超均提示"左心室明显扩大,左心室收缩功能减低",双肾超声提示"双肾明显增大",其中病例1双肾B超可见多发性囊肿。基因检测发现2例患儿均携带PKHD1基因复合杂合突变。既往未见常染色体隐性遗传性多囊肾合并扩张型心肌病的病例报道,心肌病是否为PKHD1基因突变表型的一部分有待更多的病例研究及功能验证。     

Prenatal diagnosis of autosomal recessive polycystic kidney disease]

OBJECTIVE: Prenatal ultrasonographic detection of autosomal recessive polycystic kidney disease (ARPKD) is of poor reliability, especially in early pregnancy. Molecular genetics allows earlier diagnosis, from 11 weeks of gestation; however, since only indirect diagnosis is possible--the ARPKD gene being localized on chromosome 6 but not identified--the feasibility of molecular diagnosis requires several conditions: definitive diagnosis in the index case, availability of index case and parents' DNA, genetic informativity of the family at the ARPKD locus. Results and limits of this method are analyzed, using a series of 56 requests for prenatal diagnosis. RESULTS: In eight of the 56 families ARPKD was excluded on the basis of histological (seven cases) and/or genetic (two cases) criteria. Molecular study was impossible in three families due to the lack of index case's DNA, and two other families were non-informative. Among the 43 families in which prenatal diagnosis was feasible, analysis of the haplotype of 35 fetuses issued from 29 families showed that 11 fetuses with the same haplotypes as that of the index case were affected, while 24 were not. No false positive or false negative result was reported. CONCLUSIONS: Early and reliable prenatal diagnosis of recessive polycystic kidney disease is possible in nearly 80% of affected families.     

Pyramidal hyperechogenicity in autosomal recessive polycystic kidney disease resembling medullary nephrocalcinosis

Striking pyramidal hyperechogenicity resembling the sonographic appearance of medullary nephrocalcinosis was found in autosomal recessive polycystic kidney disease (ARPKD). This sonographic pattern is distinctly different from those described previously in ARPKD.     

New approaches to the autosomal recessive polycystic kidney disease patient with dual kidney–liver complications

Improved neonatal medical care and renal replacement technology have improved the long‐term survival of patients with ARPKD. Ten‐yr survival of those surviving the first year of life is reported to be 82% and is continuing to improve further. However, despite increases in overall survival and improved treatment of systemic hypertension and other complications of their renal disease, nearly 50% of survivors will develop ESRD within the first decade of life. In addition to renal pathology, patients with ARPKD develop ductal plate malformations with cystic dilation of intra‐ and extrahepatic bile ducts resulting in CHF and Caroli syndrome. Many patients with CHF will develop portal hypertension with resulting esophageal varices, splenomegaly, hypersplenism, protein losing enteropathy, and gastrointestinal bleeding. Management of portal hypertension may require EBL of esophageal varices or porto‐systemic shunting. Complications of hepatic involvement can include ascending cholangitis, cholestasis with malabsorption of fat‐soluble vitamins, and rarely benign or malignant liver tumors. Patients with ARPKD who eventually reach ESRD, and ultimately require kidney transplantation, present a unique set of complications related to their underlying hepato‐biliary disease. In this review, we focus on new approaches to these challenging patients, including the indications for liver transplantation in ARPKD patients with severe chronic kidney disease awaiting kidney transplant. While survival in patients with ARPKD and isolated kidney transplant is comparable to that of age‐matched pediatric patients who have received kidney transplants due to other primary renal diseases, 64–80% of the mortality occurring in ARPKD kidney transplant patients is attributed to cholangitis/sepsis, which is related to their hepato‐biliary disease. Recent data demonstrate that surgical mortality among pediatric liver transplant recipients is decreased to <10% at one yr. The immunosuppressive regimen used for kidney transplant recipients is adequate for most liver transplant recipients. We therefore suggest that in a select group of ARPKD patients with recurrent cholangitis or complications of portal hypertension, combined liver–kidney transplant is a viable option. Although further study is necessary to confirm our approach, we believe that combined liver–kidney transplantation can potentially decrease overall mortality and morbidity in carefully selected ARPKD patients with ESRD and clinically significant CHF.     

Appearance of autosomal recessive polycystic kidney disease in magnetic resonance imaging and RARE-MR-urography

Purpose. To describe the appearance of autosomal recessive polycystic kidney disease (ARPKD) on MRI and RARE-MR urography. Materials and methods. Seven boys and one girl (aged 3 months to 14 years, median 2.5 years) were evaluated. Images were obtained with 0.23-T and 1.5-T MR systems using T1-weighted (T1-W) spin-echo, T2-weighted (T2-W) turbo-spin-echo and RARE-MR-urography sequences. Signal intensities, morphological appearance of the affected kidneys and, specifically, the picture of the urinary tract on RARE-MR-urography were evaluated. Results. All children showed kidney enlargement, reniform but humpy kidney shape, homogeneously grainy renal parenchyma, normal renal pelvis and normal calyces. Signal intensity was hyperintense in T2-W images in all cases. In six cases (n = 7), T1-W images were hypointense. On RARE-MR urography a hyperintense, linear radial pattern was seen in the cortex and medulla which represents the characteristic microcystic dilatation of collecting ducts in ARPKD. Three boys and the girl presented with a few circumscribed small subcapsular cysts. Conclusions. In order to confirm the diagnosis of ARPKD, RARE-MR urography seems to be a non-invasive imaging tool that shows directly the microcystic dilated water-filled collecting ducts. Received: 14 September 1999/Accepted: 24 September 1999     

Clinical characteristics and mutation analysis of three Chinese children with autosomal recessive polycystic kidney disease

Background

There are few studies on the genotypes and phenotypes of autosomal recessive polycystic kidney disease in Chinese patients.

Methods

PKHD1 mutations in three children were detected with PCR and direct sequencing, and their clinical data were retrospectively reviewed.

Results

All of the children had bilateral enlarged polycystic kidneys, congenital hepatic fibrosis and intrahepatic bile duct dilatation. One of three children had classical multiple small cysts throughout the kidneys, and the other two children had bilateral multiple renal cysts of various sizes. Two children had abnormally shaped livers, portal hypertension and splenomegaly. Two heterozygous mutations (p.T36M, and p.P137S) were detected in Patient 1 and two were detected in Patient 2 (p.L2658X and p.V836A). One heterozygous mutation (p.L1425R) was detected in Patient 3.

Conclusions

The study shows that renal and liver phenotypes of the Chinese children varied. Five mutations were identified in the three children, three of which were novel mutations.     

The emergence of hepatic fibrosis and portal hypertension in infants and children with autosomal recessive polycystic kidney disease

Long-term imaging and clinical findings are reported in six children whose polycystic kidney disease was detected in infancy or early childhood. Over time (2 years to 20 years) all patients developed portal hypertension from hepatic fibrosis, a problem primarily noted in recessive pattern polycystic kidney disease. Mild renal failure (two patients) was accompanied by serious systemic hypertension in the same patients. In one family, one of the babies also showed dilated right hepatic ducts. Imaging studies included urography and CT although recently ultrasonography was the method of choice. The relative renal and hepatic manifestations in these patients so changed with time that it would seem fallacious to attempt to use rigid classifications based on findings at initial diagnosis.     

Individualized concept for the treatment of autosomal recessive polycystic kidney disease with end‐stage renal disease

Management of children with autosomal recessive polycystic kidney disease (ARPKD) who develop end‐stage renal disease (ESRD) remains challenging because of concomitant liver disease. Patients with recurrent cholangitis are candidates for liver‐kidney transplantation, while the treatment for patients with splenomegaly and pancytopenia due to portal hypertension is controversial. Herein, we report 7 children who were treated using an individualized treatment strategy stratified by liver disease. Two patients with recurrent cholangitis underwent sequential liver‐kidney transplantation, while 4 patients with splenomegaly and pancytopenia but without recurrent cholangitis underwent splenectomy followed by isolated kidney transplantation. The remaining patient, who did not have cholangitis and pancytopenia, underwent isolated kidney transplantation. Blood cell counts were normalized after splenectomy was performed at the median age of 8.7 (range, 7.4‐11.7) years. Kidney transplantation was performed at the median age of 8.8 (range, 1.9‐14.7) years in all patients. Overwhelming post‐splenectomy infections and cholangitis did not occur during the median follow‐up period of 6.3 (range, 1.0‐13.2) years. The estimated glomerular filtration rate at the last follow‐up was 53 (range, 35‐107) mL/min/1.73 m². No graft loss occurred. Our individualized treatment strategy stratified by recurrent cholangitis and pancytopenia can be a feasible strategy for children with ARPKD who develop ESRD and warrants further evaluation.     

Successful transplantation in a child with rapid progression of autosomal recessive polycystic kidney disease associated with a novel mutation

Autosomal recessive polycystic kidney disease (ARPKD) is the most common pediatric renal cystic disease with liver involvement. The vast majority of patients with ARPKD carry mutations in the recently characterized PKHD1 gene on chromosome 6p12. A Turkish female demonstrated rapid growth of both kidneys after delivery. Accelerated growth of both kidneys and increasing respiratory distress necessitated right-sided nephrectomy at the age of three months. Because of persistent dyspnea and ongoing growth of the remaining kidney, the second kidney also had to be removed one month later. Biopsies taken from the kidney and the liver confirmed the diagnosis of ARPKD histologically. Renal ultrasound of the patient's consanguineous parents and her older brother showed normal results. PKHD1 mutation analysis yielded a novel homozygous missense mutation (c.1116C >G, F372L) in exon 14, coding for an Ig-like domain (TIG), possibly involved in the increased growth of the kidneys. Peritoneal dialysis was performed for 12 months. The patient had successful transplantation at the age of 15 months and is doing well with actual immunosuppression with cyclosporine, mycophenolate mofetil, and prednisolone. In conclusion, the present case clearly demonstrates the favorable outcome of a child with severe ARPKD after bilateral nephrectomy, pre-emptive dialysis, and successful transplantation.     

Four pediatric patients with autosomal recessive polycystic kidney disease developed new‐onset diabetes after renal transplantation

NODAT is increasingly prevalent. Compared with adult recipients, NODAT is less prevalent in pediatric renal transplant recipients; however, some risk factors for its development in young patients have been defined. We report four pediatric renal transplant recipients with ARPKD who developed NODAT. We review the current pediatric NODAT literature and hypothesize that ARPKD may be an additional risk factor for NODAT.     

Ezrin distribution is abnormal in principal cells from a murine model of autosomal recessive polycystic kidney disease

Abnormalities in cell proliferation and intracellular signaling are features of inherited human and murine polycystic kidney diseases (PKD), regardless of the primary genetic defects. Loss of protein kinase A regulation of cell proliferation has been reported in the murine C57BL/6JCys1cpk-/- (cpk) model of autosomal recessive PKD. Qualitative differences in protein kinase A subunit distribution were observed between filter-grown cultures of noncystic- (C57BL/6J mice) and cystic cpk-derived principal cells. It was hypothesized that protein kinase A subunit distribution differences were mediated by differences in A-kinase anchoring protein (AKAP) expression, so expression of four AKAPs was examined in filter-grown cultures of primary murine cystic- and noncystic-derived principal cells. AKAP-KL expression was ambiguous, but mAKAP, AKAP95, and ezrin were expressed at expected molecular sizes and cellular locations in noncystic-derived cells. Perinuclear mAKAP and nuclear AKAP95 were distributed normally in cpk-derived cells. Expression of AKAP95 in cystic epithelium was diminished relative to controls, and ezrin expression was modestly decreased and abnormally distributed within a region near the apical surface. Qualitative differences were observed in ezrin location in response to medium change or stimulation with epidermal growth factor which suggested cell-specific differences may result from the cpk mutation or the abnormal epidermal growth factor receptor phenotype that characterizes PKD. Ezrin has been implicated in tubulogenesis, so altered ezrin expression or function could be disruptive. If PKD mutations that contribute to PKD pathogenesis are postulated to disrupt normal tubular development, perhaps the mechanism includes altered ezrin function and abnormal protein kinase A targeting.