Polycystic kidney disease and other genetic kidney disorders

Cystic kidney diseases encompass a range of genetic disorders in which the primary cilia of the cells are affected and thereby cysts form as a result. There are an increasing range of cystic renal diseases recognized due to the advances in genomics. The most common genetic kidney condition is autosomal dominant polycystic kidney disease (ADPKD). ADPKD leads to renal failure in adulthood. In children, hypertension is common and if treated, may slow down renal decline. The most common cystic kidney disease causing renal failure in children is autosomal recessive polycystic kidney disease (ARPKD). ARPKD also affects the liver. These conditions often have extra-renal features which also need to be addressed. Until recently, treatments were mainly supportive but now it is possible to slow down development of cyst formation and renal decline in ADPKD. This raises hope for treatment for other cystic renal conditions as more genes are identified and underlying mechanisms defined.     

儿童肾囊性疾病的诊治

Potter分型将儿童肾囊性疾病分为4型:常染色体隐性遗传性多囊性肾病、多囊性肾发育不良、常染色体显性遗传性多囊性肾病、梗阻性囊性发育不良肾.此外,单纯性肾囊肿、发生在肾肿瘤及其他伴囊性肾病的综合征也可引起肾脏呈囊性改变.这类病由于其发病机制和病理基础不同,临床诊断及治疗方案选择亦不同,要正确诊断这类疾病,需要仔细分类并查明病因.该文就儿童常见的肾囊性疾病进行综述.     

Unilateral abdominal mass: an unusual presentation of autosomal dominant polycystic kidney disease in children

Autosomal dominant polycystic kidney disease is rarely diagnosed in infancy or childhood. The renal involvement is typically bilateral. We describe two children with ADPKD (autosomal dominant polycystic kidney disease) presenting with a unilateral renal mass. The value of a careful genetic history and the role of sonography will be discussed.     

Morphometric studies of cystic and tubulointerstitial kidney diseases with hepatic fibrosis in children

Portal tract fibrosis with biliary ductular enlargement or proliferation occurs in a number of genetic diseases that have cystic or tubulointerstitial renal lesions. These include some with renal cystic disease such as autosomal recessive diseases (e.g., infantile polycystic disease, juvenile polycystic disease, and Meckel's syndrome), autosomal dominant diseases (e.g., adult polycystic disease) and, rarely, tuberose sclerosis and dominant glomerulocystic disease. Portal tract fibrosis with biliary enlargement and proliferation occurs also with tubulointerstitial kidney diseases. These probably include at least three disorders in the category nephronophthisis-congenital hepatic fibrosis (one autosomal recessive disease and two either autosomal or X-linked recessive diseases) plus Jeune's syndrome (the tubulointerstitial diseases Fanconi's familial nephronophthisis and anti-tubular membrane antibody disease do not regularly cause hepatic fibrosis). Morphometric data on ratios of bile ductules to connective tissue in hepatic portal tracts show high values for infantile polycystic disease (mean, 0.616) compared to lower values for juvenile polycystic disease (mean, 0.286). That the cystic renal lesions of the first two diseases differ in type and time course is known. Similar data on ratios of glomeruli plus tubules to connective tissue in renal cortices and of tubules to connective tissue in outer medullary zones of kidneys, respectively, are as follows: for Fanconi's nephronophthisis, 0.445 and 0.197; for anti-tubular basement membrane antibody disease, 0.585 and 0.164; and for the three types of nephronophthisis-congenital hepatic fibrosis studied, 0.668 and 0.446, 1.39 and 0.921, and 1.18 and 0.12. These data support clinical impressions that the category nephrophthisis-congenital hepatic fibrosis includes more than one disease entity.     

Morphometric Studies of Cystic and Tubulointerstitial Kidney Diseases with Hepatic Fibrosis in Children

Portal tract fibrosis with biliary ductular enlargement or proliferation occurs in a number of genetic diseases that have cystic or tubulointerstitial renal lesions. These include some with renal cystic disease such as autosomal recessive diseases (e.g., infantile polycystic disease, juvenile polycystic disease, and Meckel's syndrome), autosomal dominant diseases (e.g., adult polycystic disease), and, rarely, tuberose sclerosis and dominant glomerulocystic disease. Portal tract fibrosis with biliary enlargement and proliferation occurs also with tubulointerstitial kidney diseases. These probably include at least three disorders in the category nephronophthisis-congenital hepatic fibrosis (one autosomal recessive disease and two either autosomal or X-linked recessive diseases) plus Jeune's syndrome (the tubulointerstitial diseases Fanconi's familial nephronophthisis and anti-tubular membrane antibody disease do not regularly cause hepatic fibrosis). Morphometric data on ratios of bile ductules to connective tissue in hepatic portal tracts show high values for infantile polycystic disease (mean, 0.616) compared to lower values for juvenile polycystic disease (mean, 0.286). That the cystic renal lesions of the first two diseases differ in type and time course is known. Similar data on ratios of glomeruli plus tubules to connective tissue in renal cortices and of tubules to connective tissue in outer medullary zones of kidneys, respectively, are as follows: for Fanconi's nephronophthisis, 0.445 and 0.197; for anti-tubular basement membrane antibody disease, 0.585 and 0.164; and for the three types of nephronophthisis-congenital hepatic fibrosis studied, 0.668 and 0.446, 1.39 and 0.921, and 1.18 and 0.12. These data support clinical impressions that the category nephrophthisis-congenital hepatic fibrosis includes more than one disease entity.     

Association of congenital hepatic fibrosis with autosomal dominant polycystic kidney disease

The association of autosomal recessive polycystic kidney disease (ARPKD) with congential hepatic fibrosis (CHF) is well known; a rare occurrence is that of congenital hepatic fibrosis with autosomal dominant polycystic kidney disease (ADPKD). We report a family with ADPKD in which congenital hepatic fibrosis with severe portal hypertension (PHT) presented in a 4-year-old girl; the kidneys were initially normal. Typical changes of autosomal dominant polycystic kidney disease developed in the next decade and were also found in the mother and sister (neither of whom had any evidence of portal hypertension). Severe variceal bleeding was treated by sclerotherapy and beta receptor blocade.     

A 4-year-old girl with autosomal dominant polycystic kidney disease complicated by a ruptured intracranial aneurysm

In patients with autosomal dominant polycystic kidney disease (ADPKD), intracranial aneurysms (ICAs) are extrarenal manifestations and may result in serious and potentially fatal outcome following rupture. Although ICAs are a well-known complication of ADPKD, nearly all cases of ICA occurring in the context of ADPKD are adults. Here, we report the case of a Japanese girl with ADPKD who developed a subarachnoid haemorrhage (SAH) due to a ruptured ICA at the age of 4 years. Conclusion:This report is intended to raise awareness that the use of noninvasive screening techniques such as three-dimensional CT angiography or magnetic resonance angiography to detect intracranial aneurysms should also be performed in paediatric patients with autosomal dominant polycystic kidney disease.     

Sonographically detectable cysts in polycystic kidney disease in newborn and young infants

Autosomal dominant (adult type) and autosomal recessive (infantile type) polycystic kidney disease are 2 distinct forms of hereditary cystic renal disease with differing pathologic and clinical features. Glomerulocystic kidney disease is probably a separate entity, whose pathologic features may closely resemble those of autosomal dominant polycystic kidney disease, especially in small infants. An example of each of these conditions in a small infant is presented, all of which had sonographically detectable cysts. Pathologic correlation was available in each case. While there are typical sonographic features of autosomal dominant and autosomal recessive polycystic kidney disease in newborn and young infants, there is no specific appearance of either condition, and glomerulocystic kidney disease can apparently resemble either one. Other investigations, particularly family studies and pathologic verification, are important in order to establish the correct diagnosis.     

Cystic kidneys in children

From 1976-1987 a total of 26 infants and children with polycystic kidney disease were treated at the Children's Hospital of the Medical School Hannover. 13 of them suffered from infantile recessive polycystic kidney disease (IRPKD), and 13 from adult dominant polycystic kidney disease (ADPKD). IRPKD was diagnosed at a median age of 0.33 years (range 1 day-13 years), ADPKD at 6.0 years (3 days-14 years). Of those with IRPKD two infants died from bacterial infection and two others developed terminal renal insufficiency at the age of 8 years, while the others are living and 1-20 years old. All those suffer from severe arterial hypertension and have reduced renal function, but only 5 developed signs of liver fibrosis. Of those with ADPKD one infant died from sepsis and renal insufficiency, while the others are well and now 2-17 years old. Only one child needs an antihypertensive treatment. The most important criteria to differentiate IRKPD and ADKPD in children are the genetic transmission, age of first manifestation, hypertension and renal function. The prognosis is much more severe in IRPKD than in ADPKD, but is not as infaust in IRPKD as often assumed.     

Polycystic kidney disease in children

Polycystic renal diseases in children include 2 pathologically and genetically distinct diseases: autosomal recessive polycystic kidney disease (ARPKD), incorrectly called the "infantile form", characterized by a constant hepato-renal involvement, and autosomal dominant polycystic kidney disease, often termed the "adult form", which is more and more frequently detected in children as a result of advances in renal imaging techniques. The differential diagnosis is not based on age at discovery, clinical symptoms or renal imaging, which may all be similar in the 2 diseases, but on the presence, detected by either pathology or ultrasonography, of the biliary dysgenesis specific to ARPKD, and mainly on the mode of inheritance, confirmed by the results of ultrasonography in parents and grandparents.     

Nephrocalcinosis in a child with autosomal dominant polycystic kidney disease and a prolapsing ectopic ureterocele

Although autosomal dominant polycystic kidney disease commonly presents in adults, it can occur in children. Usually, renal calcification in patients with autosomal dominant polycystic kidney disease is manifested as calculi or as hemorrhage into a renal cyst. An ectopic ureterocele is a well-known finding in patients with renal duplication. To our knowledge, this is the first case report of a child who had combined findings of autosomal dominant polycystic kidney disease, nephrocalcinosis, and an obstructing ectopic ureterocele.     

Immunocytochemical Studies of the Distribution of Alpha and PI Isoforms of Glutathione S-Transferase in Cystic Renal Diseases

We describe immunohistochemical studies of the expression of alpha and pi class glutathione S-transferases (GSTs) in normal fetal kidneys. These define, in greater detail, changes in expression of alpha isoforms in the proximal tubule. At about 36 weeks of gestation expression of alpha isoforms was down-regulated in the distal tubules and collecting ducts while pi was expressed throughout the nephron. Tubular expression of alpha isoforms was restricted to the part adjacent to the glomerulus; cells farthest from the glomerulus were negative. After 40 weeks of gestation, alpha isoforms were expressed along the entire proximal tubule, while pi was restricted to the distal tubule and collecting ducts. GST expression was also studied in multicystic renal dysplasia, autosomal recessive polycystic kidney disease, and autosomal dominant polycystic kidney disease to determine whether the patterns of expression of alpha and pi isoforms allow identification of the origin of the cysts that characterize these diseases. Cysts were lined by epithelia that were strongly positive for alpha and pi isoforms. The epithelia of noncystic nephrons in renal cystic dysplasia demonstrated delayed maturity, suggesting that GST expression was dependent on the stage of development and not length of gestation.     

小儿囊肿性肾病47例

目的探讨小儿囊肿性肾病的常见病因及其临床特点。方法本院1995年1月～2006年12月共收治47例囊肿性肾病患儿。男31例,女16例;诊断时年龄1h～14岁;回顾分析其病因和临床特点。结果遗传性21例（44.68%）。包括常染色体隐性遗传多囊肾病（ARPKD）16例（34.04%）,肾单位肾痨（NPH）5例（10.64%）;发育异常24例（51.07%）。包括髓质海绵肾（MSK）13例（27.66%）,囊肿性肾发育不良（CRD）10例（21.28%）及孤立多房性肾囊肿（SMC）1例（2.13%）;获得性2例（4.25%）,均为单纯性肾囊肿（SRC）。16例ARPKD囊肿分布于皮质和髓质,肾衰竭12例（75%）,肾脏外损害9例（56.25%）。5例NPH囊肿分布于皮髓质交界处,肾衰竭5例（100%）,缺血性视网膜炎致盲1例（20%）。13例MSK囊肿局限于肾锥体,各有3例（23.08%）表现为继发性肾结石、泌尿系感染（UTI）和远端肾小管酸中毒,另2例（15.38%）表现为继发性肾积水,肾衰竭2例（15.38%）与病程长、结石并反复感染有关。10例CRD均为单肾囊性变,表现为腹部包块7例（70%）,宫内诊断5例（50%）。SRC2例和SMC1例均为局灶性肾囊肿,仅表现为腹部包块,手术切除后痊愈。结论小儿囊肿性肾病以遗传性及发育异常性疾病为主,常见病因有ARPKD、NPH、MSK和CRD;ARPKD和NPH为进行性肾衰竭或肾外病变,预后差;MSK和CRD属肾脏发育异常,尽早诊断和治疗,预后好。     

Novel association of familial testicular germ cell tumor and autosomal dominant polycystic kidney disease with PKD1 mutation

Adolescent brothers were diagnosed with testicular germ cell tumors within the same month. Both were found to have multiple renal cysts on pretreatment imaging done for staging. The proband, his brother, and their mother, were all found to have a novel splice variant in intron 8 of the PKD1 gene by clinical exome sequencing. This is the second family reported with both familial testicular germ cell tumor (FTGCT) and autosomal dominant polycystic kidney disease (ADPKD), and the first described association of FTGCT with a splice variant in PKD1. We suggest that this novel variant in PKD1 may convey increased risk for FTGCT in addition to causing ADPKD.     

A case of familial bilateral polycystic kidney

The paper describes a case of bilateral polycystic kidney in a 14-year-old whose father and 3 brothers are also affected by bilateral renal cystic dysplasia (as is a paternal aunt), while a paternal uncle is affected by constant hematuria with no ultrasound signs of renal cystic dysplasia. The case in question is an adult type of dominant autosomal polycystic renal dysplasia, affecting all the males in the family and also a female within the family nucleus. The case is described in the light of the most recent reports on the subject and the problem of prevention is also discussed.     

Outcome of Multi-Cystic Dysplastic Kidneys in Children

Background:

Renal cystic diseases are important causes of chronic kidney disease (CKD).

Objectives:

We report the pattern of renal cystic disease in children and evaluate the outcome of children with multicystic dysplastic kidney (MCDK).

Patients and Methods:

Retrospective study of all children with cystic kidney diseases at King Abdulaziz University hospital from 2006 to 2014.

Results:

Total of 55 children (30 males); 25 MCDK, 22 polycystic kidney diseases (PKD), 4 nephronophthises and 4 renal cysts. Consanguinity was positive in 96.2%. MCDK and simple renal cyst patients had good renal function while PKD and nephronophthisis developed renal impairment. Most MCKD were diagnosed ante-natally, 16 of them were followed up for 3.4 (1.97) year. Their last creatinine was 33.9 (13.5) umol/L. MCDK was spontaneously involuted at mean age of 2.6 (1.3) years in 56%.

Conclusions:

MCDK is the commonest cystic renal disease and diagnosed ante-natally in the majority of cases. It has a good prognosis.     

Radiologic features of “adult type” polycystic kidney disease in the neonate

Two cases are reported of adult type polycystic renal disease (autosomal dominant) presenting in the newborn as a unilateral abdominal mass. The radiographic findings in the involved kidney simulated the ectatic tubules of infantile polycystic disease, yet histologic examination was consistent with the adult variety and both infants had other family members with adult type polycystic kidneys. These cases emphasize some of the ambiguities that exist in the definition and classification of polycystic renal disease.     

Cystic renal involvement in tuberous sclerosis

We describe two cases of unusual presentation of tuberous sclerosis with cystic renal involvement. A 19-month-old white male who was initially misdiagnosed as having polycystic kidney disease of "adult-type" developed petit mal seizures and small "ash-leaf" depigmented areas, raising a suspicion of tuberous sclerosis. Computerized tomography (CT) of the brain revealed periventricular calcifications, confirming the diagnosis of tuberous sclerosis. A 15 3/4-year-old black female with tuberous sclerosis showed acceleration of renal failure. Computerized tomography scan of the abdomen showed cystic lesions of the kidneys. In young children with cystic renal involvement but a negative family history of tuberous sclerosis or polycystic kidney disease, a CT scan of the brain should assist in the diagnosis. A CT scan or ultrasound examination of the abdomen will differentiate cystic renal lesions from angiomyolipoma of the kidneys.     

Ultrasonographic features of glomerulocystic disease in infancy: similarity to infantile polycystic kidney disease

Glomerulocystic kidney disease (GCD) is an unusual condition characterized pathologically by cystic dilatation of Bowman's space and the first portion of the proximal convoluted tubule. We report the serial ultrasound findings in an asymptomatic infant with GCD which were initially confused with infantile polycystic kidney disease. We emphasize the nonspecificity of ultrasonographic findings in cystic renal disease in early infancy and suggest a protocol for the diagnostic work-up of bilateral renal cystic disease in children.     

MOLECULAR BIOLOGY OF AUTOSOMAL DOMINANT POLYCYSTIC KIDNEY DISEASE

Among the prevalent human genetic disorders, human autosomal dominant polycystic kidney disease is certainly one of the most challenging, both from a clinical and a fundamental perspective. In the recent years, important progress opened novel research avenues to elucidate the genetic basis, the cellular pathophysiologic mechanisms and the molecular function of genes and proteins involved in autosomal dominant polycystic kidney disease.