Polycystic kidney diseases in childhood

Educational Case: Autosomal Dominant Polycystic Kidney Disease

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, see http://journals.sagepub.com/doi/10.1177/2374289517715040.¹.

Diagnostic of Early Onset Polycystic Kidney Disease in Neonates

Polycystic kidney disease represented by autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD) have a major impact of mortality in children. We conducted a study of a premature infant with an estimated gestation date of 32 weeks with a presumptive prenatal diagnosis of right polycystic kidney. A 28-year-old primigravida with pre-eclampsia was admitted at the gynecology unit of Clinical Emergency County Hospital of Craiova. The clinical examination revealed a large abdominal distention due probably to the right polycystic kidney, suspected on prenatal ultrasound and radiography. The preterm neonate undergone right nephrectomy 5 days after birth. Histopathology of the kidney was performed in the Pathology Department of the Emergency County Hospital of Craiova and in the Center for Microscopic Morphology and Immunology of U.M.F. of Craiova. Microscopy revealed dilated cysts lined by simple cuboidal or flattened epithelium, and islets of remnant kidney parenchyma separated by edematous stroma. Immunohistochemistry for CD34 revealed incomplete blood arcades which did not seem to be in contact with all the tubular elements of the parenchyma, when compared to a control age-matched kidney. The patient had a favorable postoperative evolution, she was clinically stable on discharge from the hospital with a follow-up strategy including genetic testing.

Pathophysiology of childhood polycystic kidney diseases: new insights into disease-specific therapy

Autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD) are significant causes of morbidity and mortality in children and young adults. ADPKD, with an incidence of 1:400 to 1:1,000, affects more than 13 million individuals worldwide and is a major cause of end-stage renal disease in adults. However, symptomatic disease is increasingly recognized in children. ARPKD is a dual-organ hepatorenal disease with an incidence of 1:20,000 to 1:40,000 and a heterozygote carrier rate of 1 in 70. Currently, no clinically significant disease-specific therapy exists for ADPKD or ARPKD. The genetic basis of both ADPKD and ARPKD have been identified, and delineation of the basic molecular and cellular pathophysiology has led to the discovery that abnormal ADPKD and ARPKD gene products interact to create "polycystin complexes" located at multiple sites within affected cells. The extracellular matrix and vessels produce a variety of soluble factors that affect the biology of adjacent cells in many dynamic ways. This review will focus on the molecular and cellular bases of the abnormal cystic phenotype and discuss the clinical translation of such basic data into new therapies that promise to alter the natural history of disease for children with genetic PKDs.

White-blue pyelocalyceal cyst with hydrotic glomerulonephritis

A 5-month-old male infant presented with a 15 day history of distension of abdomen. On clinical examination, a soft lump was palpable in the left lumbar region. Radiological findings suggested an enlarged non-functional left kidney with ureteropelvic adhesive obstruction. The left renal mass was excised and submitted for histopathological examination. The excised renal mass was cystic with its wall partly white and partly blue. Gross and histopathological findings were diagnostic of a white-blue pyelocalyceal cyst with hydrotic glomerulonephritis. This entity needs to be differentiated from a large number of other cystic diseases of the kidney. Intrauterine screening and diagnosis may be significant for a possible early intrauterine uro-laparoscopic recanalisation of the pyeloureteral obstruction to save the affected kidney.

Diagnosis and management of childhood polycystic kidney disease

A number of syndromic disorders have renal cysts as a component of their phenotypes. These disorders can generally be distinguished from autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD) by imaging studies of their characteristic, predominantly non-renal associated abnormalities. Therefore, a major distinction in the differential diagnosis of enlarge echogenic kidneys is delineating ARPKD from ADPKD. ADPKD and ARPKD can be diagnosed by imaging the kidney with ultrasound, computed tomography, or magnetic resonance imaging (MRI), although ultrasound is still the method of choice for diagnosis in utero and in young children due to ease of use, cost, and safety. Differences in ultrasound characteristics, the presence or absence of associated extrarenal abnormalities, and the screening of the parents >40 years of age usually allow the clinician to make an accurate diagnosis. Early diagnosis of ADPKD and ARPKD affords the opportunity for maximal anticipatory care (i.e. blood pressure control) and in the not-too-distant future, the opportunity to benefit from new therapies currently being developed. If results are equivocal, genetic testing is available for both ARPKD and ADPKD. Specialized centers are now offering preimplantation genetic diagnosis and in vitro fertilization for parents who have previously had a child with ARPKD. For ADPKD patients, a number of therapeutic interventions are currently in clinical trial and may soon be available.

Pyloric stenosis in a newborn baby with polycystic kidneys

Patients with infantile hypertrophic pyloric stenosis (IHPS) have an increased incidence of renal anomalies. Association of IHPS and polycystic kidney disease (PKD) has been reported in three case histories. It is uncertain whether the association of PKD and IHPS is due to genetics, a pathophysiological link or a chance phenomenon. One hypothesis linking the two conditions is nitric oxide synthetase (NOS) deficiency. NOS deficiency leads to lack of locally available nitric oxide causing a failure of smooth muscle relaxation. It is therefore plausible that NOS deficiency plays a part in the pathogenesis of pyloric stenosis, hypertension and cyst development in autosomal-dominant PKD.

Perinatal assessment of hereditary cystic renal diseases: the contribution of sonography

The aims of this review article were to clarify the steps that may lead to a proper diagnosis of fetal and neonatal renal cystic diseases. All the hereditary cystic diseases are reviewed and a classification is proposed. The various sonographic patterns that can be used to ascertain the diagnosis are also reviewed. Finally, tables with differential diagnoses are presented to help the reader in the work-up of such pathologies.

Ambulatory blood pressure correlates with renal volume and number of renal cysts in children with autosomal dominant polycystic kidney disease

OBJECTIVE

In adult patients with autosomal dominant polycystic kidney disease (ADPKD) renal volume was found to be significantly greater in hypertensive compared to normotensive patients. The purpose of this study was to find out if blood pressure (BP) is related to renal size also in children with ADPKD, for example, in an early stage of the disease.

METHOD AND RESULTS

Sixty-two children with ADPKD and normal renal function (mean age 12.3+/-4.3 years) were examined by renal ultrasound and ambulatory BP monitoring (ABPM). Twenty-two children were hypertensive and 40 normotensive. Mean renal volume was significantly greater in hypertensive than in normotensive children (2.7+/-2.3 SDS versus 1.2+/-2.5 SDS, P<0.01) despite similar anthropometric data and renal function. Similarly the mean number of cysts was significantly higher in hypertensive patients than in normotensive (35+/-15 cysts versus 23+/-14 cysts, P<0.01). Renal volume correlated with daytime as well as with night-time systolic and diastolic BP (r=0.41-0.47, P<0.01). Correlations with renal length and the number of renal cysts were somewhat less (r=0.29-0.43, P<0.05 and 0.01, respectively).

CONCLUSIONS

This study revealed a significant relationship between renal volume, renal length and number of renal cysts and BP. It is suggested that children with ADPKD should regularly be checked for BP changes by ABPM, especially those who show increased renal size or a high number of renal cysts on ultrasound. All these children are at high risk for development of hypertension.

Abnormal nephron development associated with a frameshift mutation in the transcription factor hepatocyte nuclear factor-1 beta

BACKGROUND

The transcription factor hepatocyte nuclear factor (HNF)-1 beta functions as a homodimer or as a heterodimer with the structurally related protein HNF-1 alpha. Both are expressed sequentially in rat kidney development, with HNF-1 beta being detected from the earliest inductory phases. HNF-1 beta gene mutations are associated with a unique disorder characterized by maturity-onset diabetes of the young (MODY) and early-onset and progressive nondiabetic renal dysfunction, which may lead to chronic renal failure.

METHODS

The HNF-1 beta gene was screened for mutations in six subjects with early-onset diabetes and a history of renal dysfunction in the subjects or their families.

RESULTS

A novel frameshift mutation in exon 4 of the HNF-1 beta gene and a deletion of CCTCT at codons 328 to 329 were detected in one subject. She was diagnosed as diabetic at the age of 21 in her second pregnancy. Glucose tolerance rapidly deteriorated over 18 months as a result of beta-cell dysfunction. The HNF-1 beta mutation arose de novo on a paternal chromosome and cosegregated with renal abnormalities in her family. The proband had bilateral small cysts in normal-sized kidneys and a reduced creatinine clearance of 66 mL/min (NR 80-120). Her first pregnancy was terminated at 17 weeks following an ultrasound diagnosis of bilateral, nonfunctioning cystic kidneys. Her first-born child had a small multicystic, dysplastic right kidney and a dysplastic left kidney with a reduced creatinine clearance (40 mL/min per 1.73 m2). Histologic examination of the large (5.8 vs. 1.4 g), polycystic fetal kidneys showed no normal nephrogenesis.

CONCLUSIONS

These studies indicate that HNF-1 beta plays a central role in normal kidney development and pancreatic beta-cell function, and suggest that one mechanism by which HNF-1 beta gene mutations may cause renal dysfunction are by their effects on nephron development.

Genetic analysis of modifying loci on mouse chromosome 1 that affect disease severity in a model of recessive PKD

Using a cross between C57BL/6J and FVB/N mice, we have confirmed the localization on chromosome 1 of a modifying locus that affects the severity of polycystic kidney disease (PKD) in the juvenile cystic kidney (jck) mouse. Despite the highly significant contribution of this locus in F2 progeny of a cross between C57BL/6J and DBA/2J mice (4), a series of congenic strains carrying regions of chromosome 1 on a DBA/2J background did not show a severe disease phenotype. One possible explanation for these results is that this phenotype is caused by two linked loci, which have been separated in the congenic lines that were generated. This hypothesis is supported by the demonstration that severe PKD occurs in mice carrying a large congenic interval.

Current concepts and controversies in imaging of renal cystic diseases

Renal cystic disease compromises a diverse group of inherited and acquired entities. This article reviews the clinical, pathologic, and radiologic findings of eight renal cystic diseases. For each entity, the current concepts of pathogenesis and pathophysiology are discussed. When appropriate, controversies concerning terminology, management, and malignant potentials are addressed. Renal cystic diseases that are discussed include autosomal dominant and autosomal recessive polycystic kidney disease, medullary sponge kidney, medullary cystic disease, multicystic, dysplastic kidney, von Hippel-Lindau disease, acquired cystic kidney disease, and tuberous sclerosis.

Infundibulopelvic stenosis, multicystic kidney, and calyectasis in a kindred: clinical observations and genetic analysis

Congenital obstructive anomalies of the urinary tract usually occur sporadically. We describe inheritance in a three-generation kindred of a spectrum of kidney anomalies consistent with an autosomal-dominant mode of transmission, with incomplete penetrance, calyectasis (maternal grandmother), infundibulopelvic stenosis (uncle), and multicystic kidney (male proband, age 4 years). The proband's mother, father and half sister had normal renal imaging studies. Inheritance of informative polymorphic markers (3'-HVR, GGG1, GGG9, SM-7, KG8, and CW3) mapping close to the adult polycystic kidney disease type 1 (PKD-1) and tuberous sclerosis (TSC-2) loci on chromosome 16p was evaluated by Southern blot studies and by PCR-based, fluorescent genotyping for linkage to phenotype. The 3 affected individuals, as well as the unaffected mother (obligate carrier) and unaffected half-sister, inherit a common chromosome haplotype linked to the PKD1 locus. Our findings support the hypothesis that these anomalies may be part of a spectrum of obstructive renal dysplasia which are inherited as a simple Mendelian trait exhibiting an autosomal-dominant mode of transmission with variable expression and incomplete penetrance.

Body growth in children with polycystic kidney disease. Arbeitsgemeinschaft für Pädiatrische Nephrologie

We analysed the body growth of 121 prepubertal children with polycystic kidney disease participating in a longitudinal multicentre study. The patients were followed from an age of 1 to 9 years in girls and 1 to 10 years in boys over a mean period of 3.6 years. Children with end-stage renal disease were excluded. Fifty-four patients had the autosomal dominant form of the disease and 67 the autosomal recessive form. At last observation, 2% of patients with the dominant form and 28% of those with the recessive form had an estimated glomerular filtration rate of < 60 ml/(min 1.73 m2). At first observation, the mean height SD score (SDS) in patients with the dominant form was almost the same as in controls, whilst in those with the recessive form it was significantly decreased (girls -0.82 SDS, boys -0.68 SDS, p < 0.001). During the follow-up the height SDS decreased slightly in both groups (NS). In patients with autosomal recessive kidney disease the degree of growth retardation appeared to be related to renal function: at last observation the height of girls with an estimated glomerular filtration rate of < 60 ml/(min 1.73 m2) was more retarded than that of boys (mean -2.1 SDS versus -1.5 SDS, NS). The height SDS and renal function at last observation correlated in girls (r = 0.83, p < 0.001) but not in boys (r = 0.55) with the recessive form. No correlation was found between the height SDS and hypertension. The weight-for-height SDS at onset was significantly reduced in patients with the recessive form with decreased renal function. Our data suggest that the autosomal recessive, but not the dominant, form of polycystic kidney disease is associated with early growth retardation, which seems to be more severe in girls, probably due to the more rapid deterioration of renal function.

Polycystic kidney disease: etiology, pathogenesis, and treatment

Once viewed as hopelessly incurable disorders and the dustbin for careers in academic medicine, the polycystic kidney diseases have emerged as prime targets of pathophysiologic study and palliative and definitive treatment in the era of molecular medicine. Polycystic kidney disease (PKD) may be hereditary or acquired. The major inherited types are autosomal dominant (AD) and autosomal recessive (AR). ADPKD is caused by at least two (and possibly three) genes located on separate chromosomes, while ADPKD-1 is due to a 14 kb transcript in a duplicated region on the short arm of chromosome 16 very near the alpha-globin gene cluster and the gene for one form of tuberous sclerosis. ADPKD-2 has been assigned to the long arm of chromosome 4. ARPKD is due to a mutated gene on both copies of the long arm of chromosome 6. Cysts originate in renal tubules. Proliferation of tubule epithelial cells modulated by endocrine, paracrine, and autocrine factors is a major element in the pathogenesis of renal cystic diseases. In addition, fluid that is abnormally accumulated within the cysts is derived from glomerular filtrate and, to a greater extent, by transepithelial fluid secretion. Abnormal synthesis and degradation of matrix components associated with interstitial inflammation are additional features in the pathogenesis of renal cystic diseases. The ADPKD genotypes are characterized by bilateral kidney cysts, hypertension, hematuria, renal infection, stones, and renal insufficiency. ADPKD is a systemic disorder; cysts appear with decreasing frequency in the kidneys, liver, pancreas, brain, spleen, ovaries, and testis. Cardiac valvular disorders, abdominal and inguinal hernias, and aneurysms of cerebral and coronary arteries and aorta are also associated with ADPKD. Treatment is supportive: dietary regulation of salt and protein intake, control of hypertension and renal stones, and dialysis and transplantation at the end stage. ARPKD is a relatively rare disease that causes clinical symptoms at birth, with significant mortality in the first month of life. The cysts develop primarily in the collecting ducts because of a failure in the maturation process. Early complications include Potter's syndrome; excessive size of the kidneys, causing respiratory dysfunction; hypertension; and renal insufficiency. Hepatic fibrosis is an associated extrarenal problem that results in significant morbidity in young children and adolescents. Treatment includes supportive care, dialysis, and renal transplantation. Acquired cysts (solitary/simple) are commonplace in older persons. Multiple cysts may be seen in association with potassium deficiency, congenital disorders, metabolic diseases, and toxic renal injury.(ABSTRACT TRUNCATED AT 400 WORDS)

Animal models of polycystic kidney disease

Polycystic kidney disease (PKD) is one of the most prevalent causes of heritable renal failure. The disease is characterized by the occurrence of numerous fluid-filled cysts within the parenchyma of kidney. The cysts are epithelial in origin and expand in size, leading to crowding of normal kidney tissue. Ultimately, there is gross enlargement of the kidneys with loss of normal functions, and death usually occurs because of complications related to renal failure. Animal models of polycystic kidney disease are proving to be extremely useful for studying the molecular basis of renal cyst formation and for the isolation of genes carrying the mutations. This article describes the various animal models of polycystic kidney disease, spontaneously and experimentally derived, that have recently been identified.

Cystic kidney disease in Hajdu-Cheney syndrome

We report on 2 unrelated patients with Hajdu-Cheney acroosteolysis syndrome, who had cystic kidneys with ultrasonographic changes similar to those of autosomal dominant polycystic kidney disease. Neither had a family history of Hajdu-Cheney syndrome or polycystic kidneys, nor manifestations of any other syndrome. On the basis of the findings in these 2 patients and a review of published cases, we suggest that cystic kidneys are an important component of Hajdu-Cheney syndrome.

Hyperechoic kidneys in the newborn and young infant

Increased echogenicity of the kidney in the newborn has many causes, some of which reflect serious renal disease. The major abnormal imaging pattern is the large, diffusely hyperechoic kidney with abnormal architecture. Its differential diagnosis includes recessive and dominant polycystic kidney disease (PKD), glomerulocystic kidney disease, and diffuse cystic dysplasia. The family history and ultrasonic screening of the parents and siblings are essential in the evaluation. The identification of associated nonrenal abnormalities is important to the recognition of syndromal cystic disease. Glomerulocystic kidney disease, which comprises sporadic and syndromal forms, appears similar to dominant PKD. While renal biopsy almost always differentiates recessive from dominant PKD, renal biopsy cannot differentiate among the forms of glomerulocystic kidney disease, except in the case of tuberous sclerosis, which has unique histopathological characteristics. Other causes of the enlarged hyperechoic kidneys with abnormal architecture include renal vein thrombosis and congenital nephrotic syndrome. A second pattern is the hyperechoic small kidney with abnormal architecture. Many of these kidneys are dysplastic and associated with urinary tract obstruction. The combination of hyperechoic parenchyma and pyelocaliceal dilatation suggests obstructive cystic dysplasia. Cortical and medullary necrosis in the newborn also causes hyperechogenicity in small kidneys. A third pattern contains those kidneys with medullary hyperechogenicity, the most common cause of which in the newborn is nephrocalcinosis associated with furosemide therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Tuberous sclerosis and polycystic kidney disease

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Juvenile cystic kidneys (jck): a new mouse mutation which causes polycystic kidneys

We have characterized a new recessive mutation in the mouse which predisposes to the development of polycystic kidney disease. This mutation, called juvenile cystic kidneys (jck), arose in a transgenic line of mice, but appears unrelated to the transgene since it segregates freely from it. While focal cysts are evident in affected animals as early as three days of life and the disease is progressive, the mice are fertile and generally survive to four or more months of age. Complementation analysis indicates that the jck mutation is not allelic with three other known recessive polycystic kidney mutations (cpk and two as yet unnamed mutations), and linkage studies demonstrate it is unlikely to be allelic with a fourth (pcy). The study of these five mutations and their interactions should prove useful for understanding the mechanisms required to maintain the normal integrity of renal tubules.

Familial renal-hepatic-pancreatic dysplasia and Dandy-Walker cyst: a distinct syndrome?

Ivemark et al. first described sibs with renal-hepatic-pancreatic dysplasia (RHPD) (Ivemark BI, Oldfelt V, Zetterström R (1959): Acta Pediatr Scand 48: 1-11). Subsequent reports of affected individuals have described additional malformations and syndromes associated with RHPD. In this paper we describe 2 sibs with RHPD in association with Dandy-Walker cyst (DW). Through an examination of the pattern of associated malformations seen in RHPD we argue that RHPD-DW is a distinct monogenetic syndrome, and not an association.

Renal dysgenesis in a monozygotic twin: association with in utero exposure to indomethacin

We report oligohydramnios and renal dysgenesis in one of identical twins, which might have resulted from in utero exposure to early, prolonged high-dose indomethacin. The proposita was the second of twin girls born at 36 weeks of gestation. Pregnancy was complicated initially by polyhydramnios in both amniotic sacs and premature uterine contractions. After administration of indomethacin and terbutaline from 16 to 30 weeks' gestation, serial prenatal ultrasound examinations ultimately showed oligohydramnios in twin B and resolution of polyhydramnios in twin A. On day 5 twin B developed hematuria, hypertension, renal failure, hyponatremia, hyperkalemia, metabolic acidosis, sodium wasting and severe, transient inability to excrete potassium. Renal sonography showed enlarged, hyperechoic kidneys with almost no corticomedullary differentiation. Renal biopsy revealed immature glomeruli, dilated Bowman's spaces, dilated tubules, and interstitial fibrosis. The liver was histologically normal. Indomethacin may induce oligohydramnios and transient renal insufficiency in humans and renal dysgenesis in fetal monkeys; it might have induced the abnormalities in this patient.