Percutaneous nephrolithotomy (pcnl) in paediatric stones

PurposeTo evaluate the role and outcome of percutaneous nephrolithotomy (PCNL)in the management of paediatric urolithiasis.Material and methodsWe retrospectively reviewed the records of children who underwent PCNL procedures for renal calculi from 2004 to 2007 A total of 300 children with renal calculi were treated with PCNL. Patient's age at operation ranged from 8 months to 15 years. Patients had pre-operative blood and urine analysis, ultrasonography of kidneys, ureter, bladder and X-ray IVU. A tract was made in the prone position using fluoroscopy and ultrasound. 22 to 26 Fr sheaths with 18.0, 20.5 and 24 Fr nephroscopes were used accordingly. Ultrasound and pneumatic lithoclast alone or in combination were used for stone fragmentation.Results300 PCNL procedures were performed. Stone burden ranged from 3.1 ± 3.7 cm² (simple 2.1 ± 1.5 cm², complex 5.0 ± 8.8 cm²) with stone clearance rates of 92% and 78% in simple and complex stones respectively. During the procedure mean Hb drop was 1.36 ± 0.8 gm% while 26 (14.6%) patients required blood transfusion. Intra and post operative complications included excessive bleeding, and conversion to open surgery in 8, extravasation of fluid in 11 and 5 cases with urinary sepsis.ConclusionsPercutaneous nephrolithotomy is a suitable and safe procedure in children including the pre-school age group for both simple and complex stones.     

Clinical characteristics and metabolic abnormalities in preschool-age children with urolithiasis in southeast Anatolia

ObjectiveData on urolithiasis in preschool-age children are limited. The aim of this study was to investigate the metabolic etiology and clinical findings of preschool-age children with urolithiasis.MethodsThe medical records of 143 preschool-age children (81 boys, 62 girls, aged 2–6 years) with urolithiasis were retrospectively analyzed. Results of physical examination, serum biochemistry, and urine metabolic evaluation (including urinary citrate, oxalate, calcium, uric acid, cystine, and magnesium) were recorded.ResultsThe mean age at diagnosis was 3.7 ± 1.3 years. A family history of stone disease was found in 79.7% of patients, and 37% of parents had consanguineous marriages. The most common presenting symptoms were hematuria (33%) and urinary tract infection (UTI; 29%). Metabolic abnormalities were found in 119 (83.2%) patients, including hyperuricosuria in 24.5%, hypocitraturia in 23.8%, hyperoxaluria in 21.7%, hypercalciuria in 21.0%, cystinuria in 7.7%, and hypomagnesuria in 1.4%. Multiple metabolic abnormalities were found in 24 (16.8%) patients. Results of 28 stone analyses revealed calcium oxalate or phosphate, cystine, and uric acid in 15, nine, and four of the patients, respectively. ^99mTechnetium–dimercaptosuccinic acid renal scintigraphy revealed that 27.8% of the children with UTI had renal parenchymal scarring, with only four of them having vesicoureteral reflux.ConclusionThe most frequent metabolic abnormalities in preschool-age children with urolithiasis were hyperuricosuria and hypocitraturia. A comprehensive investigation of stone disease in children presenting with hematuria and UTI is important to prevent the development of renal parenchymal scarring.     

Metabolic stone composition in Egyptian children

ObjectiveThe composition of urinary stones in children depends on socioeconomic conditions, geography and dietary habits. Pediatric urolithiasis remains endemic in developing countries. The aim of this study was to analyze stone composition in an Egyptian patient population.Patients and methodsWe analyzed prospectively urinary stones from 100 consecutive children (73 males, 27 females), aged 14 months to 12 years. The stones were located in the upper urinary tract in 78%, lower urinary tract in 19% and both in 3%. Male patients had more lower urinary tract stones. On presentation 67% had flank pain and 37% had hematuria. Stones were treated by open surgery in 69% of patients, shockwave lithotripsy in 20% and endoscopic extraction in 13%.ResultsThe components of the upper urinary tract calculi were calcium oxalate (47%), ammonium acid urate (26%) and calcium carbonate (21%), whereas the main components of the lower urinary tract calculi were ammonium acid urate (27.2%), struvite (27.2%) and calcium carbonate (22.7%). Urinary tract infection was involved in the development of one third of the stones. Endemic stones were present in 17% of patients, and stones of metabolic origin in 15%. The etiology of stone formation remained unknown in one third of patients.ConclusionThe epidemiological profile of urinary stones in Egyptian children can now be considered intermediate between developing countries where dietary deficiencies are the main causes and developed countries where infectious and metabolic calculi are observed.     

Pediatric urolithiasis in a non-endemic country: A single center experience from The Netherlands

ObjectiveTo provide insight in causative factors of pediatric urolithiasis in The Netherlands, a non-endemic country.Patients and methodsData from 71 children with urolithiasis and stone analyses between 1996 and 2010 in the Radboud University Nijmegen Medical Centre were studied retrospectively. Patients (48 boys, 23 girls, ratio 2.1:1) were aged 0.5–18.3 years (mean 8.8, SD 5.6). All stone analyses were performed with FTIR spectroscopy.ResultsOf the 49 patients with metabolic analysis, 78% showed one (n = 15) or more (n = 23) metabolic abnormalities. Forty-seven percent had hypercalciuria (n = 23), 31% had hyperoxaluria (n = 15), 29% hypocitraturia (n = 14), 10% hyperuricosuria (n = 5), 10% cystinuria (n = 5), and 6% had hypomagnesiuria (n = 3).Sixty-one percent of the stones were composed of calcium phosphate, calcium oxalate, or a combination of those. Twenty-six percent consisted of pure or mixed magnesium ammonium phosphate, 8.3% pure or mixed urate, and 8.3% cystine.ConclusionChildren with urolithiasis in The Netherlands show stone composition similar to other Western European countries. However, a high percentage of metabolic abnormalities (78%) was found, indicating the need for extensive evaluation of pediatric urolithiasis to find underlying causes and thereby prevent stone recurrences. A close collaboration between a pediatric nephrologist and urologist is mandatory for optimal surgical and medical treatment.     

Urolithiasis in children

Twelve stones from 11 children with urolithiasis treated in the pediatric surgical department from 1976–1981 were quantitatively analyzed by X-ray diffraction. According to clinical picture and stone analysis, the cases fell into two groups: (1) children less than 3 years of age with Proteus sp. infection and staghorn phosphate stones, and (2) children of 5 years or more with uninfected calcium oxalate stones of the renal pelvis or ureter. The quantitative analyses showed that urinary stones in children have the same main types of composition as in adults but may be less complex. The 4.5 : 1 sex distribution of male: female patients, the 33% incidence of malformations of the upper urinary tract, and the 9% frequency of recurrence correspond to figures from other reports.     

Development of upper tract stones in patients with congenital neurogenic bladder

ObjectivePatients with neurogenic bladder are at increased risk of developing upper tract stones. We hypothesized that patients with lower urinary tract stone disease are at greater risk of developing upper tract stones.MethodsWe performed a 10-year retrospective case–control study of patients with neurogenic bladder to determine the association between bladder and upper tract stones. Independent risk factors for upper tract stones were assessed. Cases and controls were matched 1:1. Univariable analysis was performed by Fisher's exact test and the Mann–Whitney U test. Multivariable logistic regression was performed.Results52 cases and controls were identified. Cases were significantly more likely to be non-ambulatory, have bowel–urinary tract interposition, thoracic level dysraphism, and history of bladder stones. On multivariable analysis, independent predictors of stone formation were male sex (OR 2.82; p = 0.02), dysraphism involving the thoracic spine (OR 3.37; p = 0.014) bowel–urinary tract interposition (OR 2.611; p = 0.038), and a history of bladder stones (OR 3.57; p = 0.015).ConclusionPatients with neurogenic bladder are at increased risk for upper tract stones. The presence of bladder stones may herald the development of upper tract stones. The predictors of stone disease identified should guide prospective studies to better understand the natural history of upper tract stone development in this population.     

Changes in stone composition according to age and gender in Tunisian children

ObjectiveStudies evaluating the influence of age and gender on the distribution of the various types of pediatric urinary calculi are scarce. The aim of this study was to highlight the modification of epidemiological characteristics of this pathology according to patients' sex and age.Patients and methodsA total of 205 calculi (from 122 boys and 83 girls) were analyzed by infrared spectroscopy between 1993 and 2007; 54.6% of the patients were under 5 years.ResultsCalcium oxalate was the predominant constituent in 54.7% of stones, followed by calcium phosphate and purines (14.6% each). We found a predominance of calcium oxalate in females (59.1% vs 50.8%), and a male preponderance for struvite stones (12.3% vs 1.2%). There was an increasing prevalence of calcium oxalate stones with age in both genders (42.9% in infants vs 59.3% in older children). Purine stones were predominant in 20% of cases, but prevalence decreased with age (28.6% in infants vs 18.5% in older children).ConclusionThe increase in calcium oxalate stones in school-age children and the decrease in stones containing purines confirm a change in the etiology of urolithiasis according to age.     

An uncommon cause of acute kidney injury in young children: Cystinuria

Bilateral obstructive nephrolithiasis is a rare cause of acute kidney injury (AKI) in early childhood. As soon as the identification of AKI secondary to ureteral stone is made, it will necessitate an emergency treatment.PatientsWe report three infants with AKI caused by bilateral obstructive ureteral cystine stones. They were diagnosed with acute post-renal injury due to obstructive bilateral ureteral stones based on ultrasound scan findings. Immediately, bilateral ureteral stents were inserted for urinary drainage. Once renal function recovered to normal, each patient underwent ureteroscopy and percutaneous nephrolithotomy at the same session. Cystinuria was diagnosed by stone analysis and increased urinary excretion of cystine. Patients were advised to maintain a high fluid intake and were treated with potassium citrate in addition to tiopronin.ConclusionsWith these three cases we would like to emphasize the importance of urolithiasis in the differential diagnosis of acute renal failure in young children, since urolithiasis may only cause nonspecific symptoms in this population. An early diagnosis with prompt treatment and a close follow-up are the key for achieving the best long-term outcome in cystinuria.     

A correlation study between macro- and micro-analysis of pediatric urinary calculi

ObjectiveThe aim was investigate the relationship between macro- and micro-compositions of pediatric urinary stones by using two combined analytical techniques: Fourier transform infrared spectroscopy (FT-IR) and inductively coupled plasma-optical emission spectrometry (ICP-OES).Materials and methodsA total of 74 consecutive urinary calculi were collected from children. Each stone was divided into two equal portions. One part was analyzed by FT-IR to determine mineralogical composition. The second part underwent analysis by ICP-OES to determine the heavy metals and trace elements contents. The association between mineralogical components and elemental contents was evaluated.ResultsThe percentages of mineralogical components of the stones were 78.3% calcium oxalate monohydrate, 63.5% calcium oxalate dihydrate, 24.3% ammonium urate, 13.5% uric acid, 10.9% dahllite, 12.1% brushite, 8.1% ammonium calcium phosphate, 8.1% struvite, 4.5% cysteine, and 2.7% were xanthine. There were seven elements with significant different high concentrations; magnesium, sulfur, strontium, lead, chromium, calcium, and phosphorous. High calcium-containing stones had significant higher contents of magnesium, lead, strontium, and zinc (p < 0.05) than low calcium-containing stones. Phosphate stones had significant contents of magnesium, strontium, zinc and chromium when compared to other stones (p < 0.05).ConclusionsPediatric urinary stones have variable biochemical structures. The stones contained many significant heavy metals and trace elements in different concentrations, and phosphate stones enclosed most of the heavy and trace elements.     

Urinary stone disease in the first year of life: is it dangerous?

Purpose

We have evaluated the clinical, radiological and metabolic features of infantile urolithiasis (UL).

Materials and methods

We have reviewed the medical records of 93 children who were diagnosed as having UL before 1 year of age. We recorded patient demographics, the age at diagnosis, presenting symptoms, family history, the localizations and dimensions of stones, urinary metabolic examinations, as well as physical, laboratory, and radiologic findings. Our secondary objective was to compare some features of this group with those of older children with UL followed-up in the same clinic which were previously reported.

Results

We evaluated 93 children referred to our pediatric nephrology clinics. A family history of UL was 56.2 % in the study group. Resolution of stones was observed in 30.1 % of the cases. Urinary tract infections (UTIs) were detected in 65.9 % of females and 46.2 % of males. At least one urinary metabolic abnormality was found in 79.5 % of all the children. Most commonly seen metabolic abnormality was hypercalciuria. In all patients stones were located in kidneys except one infant who had an ureteral stone together with a kidney stone. Fifteen (16.1 %) children had an accompanying systemic disorder.

Conclusions

Among pediatric urinary stone diseases infantile UL can be regarded as a separate clinical entity. Coexistence of systemic disorders and anatomic anomalies at high frequencies may indicate a role of distinct pathogenetic mechanisms. In addition, high rates of UTIs and metabolic abnormalities in this age group justify screening for these parameters during follow-up of these children.     

Follow-up results of children with melamine induced urolithiasis: a prospective observational cohort study

Background

Melamine-contaminated milk powder was the cause of the 2008 outbreak of urolithiasis in young children and infants in China, but the prognosis of these children remains unknown. We hypothesized that urolithiasis induced by melamine-contaminated milk powder may be associated with secondary renal injury.

Methods

A total of 8335 children (≤6 years old) with a history of consuming melamine-contaminated milk powder were screened. Urine analysis and urinary system ultrasonography were performed. For children with urolithiasis, the basic information and the results of examination were recorded, and effective therapy was given. They were followed up for 6 months after the original diagnosis, and urinary microprotein profiles were measured.

Results

Of the 8335 children, 105 (1.26%) were diagnosed with melamine-contaminated milk powder-associated urolithiasis. The size of the stone was correlated with the duration of exposure to melamine. Six months later, 69.8% (67) of the children with urolithiasis passed stones (follow-up rate: 91.4%). Of the 67 children, 28 passed stones within 2 months. The higher possibility of passing a stone was correlated with the smaller diameter of the stone (P<0.001). The detection rate of abnormal urinary microprotein excretion (microalbumin, immunoglobulin G, and N-acetyl-β-D-glucosidase) was 52.4% in children with persistent stones and 38.2% in those who passed their stones. The detection rate was lower in children who passed stones within 2 months (31.8%) than in those who passed stones in 2 to 6 months (50.0%). The levels of microalbumin/creatinine and immunoglobulin G/creatinine were significantly higher in children with persistent stones than in those who passed their stones.

Conclusions

Early passage of a stone may reduce the renal injury induced by melamine-contaminated milk powder-associated urolithiasis.     

Pediatric urolithiasis with renal failure: Siut experience

PurposePediatric urolithiasis is endemic in Pakistan and constitutes about 13% of all urolithiasis cases. Urolithiasis associated with renal failure is one of the most important cause of pediatric ESRD in Pakistan.Material and methodsRetrospective analysis of 402 children with urolithiasis and associated renal failure. Ultrasound was the mainstay of radiological diagnosis and assessment.Results402 patients, age ranged between 9 months to 14 years with male female ratio of 2:1. More than 50% had a positive family history of stone disease. Apart from obstruction and infection, poor socioeconomic status (89%), rural residence (66%), neglect and delay in acquiring treatment led to renal failure in these patients. The most common signs and symptoms were fever (56.7%), flank pain (55.2%), shortness of breath (38%) and vomiting (38.3%). 105 (26%) were anuric at presentation and 297 (74%) non-anuric. More than 60% of these patients had bilateral stones and associated urinary tract infection. The initial management of these patients required dialysis mostly peritoneal dialysis in small children. Percutaneous nephrostomy with or with out dialysis was also the main stay of initial management especiallyfor those presenting with a pyonephrosis. In some “Double J” stents were also placed to relieve obstruction. Details of operative procedures for definitive treatment and type of stones will be provided in presentation.ConclusionsAbout 70% of the patients had good recovery of renal function. These good results were achieved because of the provision of free high technological treatment to all our patients under one roof with close co-operation of pediatric urology, nephrology and intensive care teams.     

An association between kidney stone composition and urinary metabolic disturbances in children

ObjectiveTo determine kidney stone composition in children and to correlate stone fractions with urinary pH and metabolic urinary risk factors.Patients and methodsWe studied 135 pediatric patients with upper urinary tract lithiasis in whom excreted or extracted stones were available for analyses. Composition of stones was analyzed. A 24-hour urine assessment included volume, pH and daily excretions of calcium, oxalate, uric acid, cystine, creatinine, phosphate, magnesium and citrate.ResultsCalcium oxalate was the major component of 73% stones, followed by struvite (13%) and calcium phosphate (9%). Uric acid was present in almost half of stones, but in rudimentary amounts. The calcium oxalate content in calculi showed a strong relationship with calciuria, and moderate association with oxaluria, magnesuria and acidification of urine. The percent content of struvite presented reverse and lower correlations with regard to the above parameters. Calcium phosphate stone proportion had low associations with urinary risk factors.ConclusionsCalciuria, oxaluria, magnesuria and low urine pH exerted the biggest influence on calcium oxalate content in pediatric renal stones. Relationships of urinary risk factors with calculi calcium phosphate content were of unclear significance. Urinary citrate excretion did not significantly correlate with kidney stone composition in children.     

Percutaneous cystolithotomy in the pediatric neuropathic bladder with laparoscopic trocar access: A modified approach useful for the augmented and native bladder,and continent urinary reservoir

ObjectiveWe present our results of percutaneous cystolithotomy with laparoscopic trocar (PCLT) access in children.Materials and methodsPCLT was performed in 13 cases. This includes 2 patients who had this performed twice for recurrent stone 12–24 months after initial surgery. Eight patients had a bladder augmentation, 2 had native bladders, and one a continent urinary reservoir. Nine patients had a reconstructed urethra. Cystoscopy was performed in all cases to assess stone burden. Under direct vision, an 18 gauge angiocatheter was placed into bladder and guidewire placed through the angiocatheter. With the bladder distended, a laparoscopic 10 mm trocar was placed under vision next to the guidewire. A 26Fr nephroscope was used via the trocar to extract the stones, utilizing laser or ultrasonic lithotripsy to fragment larger stones. Stone fragments were removed with graspers and/or the vacuum extraction technique.ResultsPCLT was successful in all cases. No complications were noted. Six cases were treated as outpatient, seven discharged home after 12–23 h observation.ConclusionsPCLT via laparoscopic trocar access is a facile and safe approach for removing stones in the pediatric neuropathic bladder. Advantages include the ability to distend the bladder with continuous flow and the larger working channel permitting use of the nephroscope to treat and extract stones.     

Effect of size and site on the outcome of extracorporeal shock wave lithotripsy of proximal urinary stones in children

ObjectiveTo determine the effect of location and size of stones on the outcome of extracorporeal shock wave lithotripsy (ESWL) in children.Patients and methodsIn 2008–2010, 150 children (median age 6.6 years) with radio-opaque ureteric and renal stones measuring ≤4 cm were treated. Exclusion criteria were coagulation disorders, pyelonephritis, distal obstruction, non-functioning kidney and hypertension. ESWL was performed under general anesthesia. Follow up period was 5–22 months.Results186 stones were treated: 76 calyceal, 92 pelvic and 18 proximal ureteral. Mean stone size was 1.3 cm. A total of 312 sessions were performed (mean per stone = 1.67 sessions). The mean number of shock waves per session was 2423.68. Overall stone-free rate was 89.24%. Having a calyceal location did not significantly affect the stone-free rate (p = 0.133). The failure rate was significantly higher (66.7%) in stones >3 cm in size (p < 0.001). Complications were encountered in 18 patients; 2 underwent auxillary ureteroscopy and 4 uretrolithotomy for treatment of steinstrasse.ConclusionESWL is a safe and effective method for treatment of stones up to 2 cm in children. Rate of auxillary procedures increases in stones >2 cm in size. About 80% of failures were associated with stone size >1.35 cm while 52.3% of completely cleared stones were associated with size <1.35 cm.     

Experience of percutaneous nephrolithotomy using adult-size instruments in children less than 5 years old

ObjectiveWe present our experience with percutaneous nephrolithotomy (PCNL) for management of large renal calculi in children less than 5 years old, and determine its safety and efficacy when using an adult-size device.Patients and methodsTwenty patients younger than 5 years old underwent PCNL between August 2003 and July 2008. After retrograde catheterization, the nephrostomy tract dilated up to 26 Fr. Then a 24-Fr rigid nephroscope was used and stones were fragmented with a pneumatic lithotripter.ResultsTwenty patients with a mean age of 3.1 years underwent 26 PCNL procedures on 24 renal units. Four patients had bilateral renal stones. Five patients (20%) had staghorn stones, as did five of the other cases with multiple stones. Four patients had undergone previous stone surgery on the same side. All of the patients were managed with only one tract. The mean stone size was 33 (20–46) mm and average operative time was 93.25 (78–174) min. Stones were completely cleared in 79.16% of patients, which increased to 91.67% with adjunctive shockwave lithotripsy. The overall complication rate was 15.38% and mean hospital stay was 5.26 (3–8) days.ConclusionPCNL is an effective and safe treatment for renal calculi in children less than 5 years old, even when using instruments designed for adults.     

Laparoscopic management of pediatric renal and ureteric stones

ObjectiveTo assess the feasibility of laparoscopy in the treatment of pediatric urolithiasis, we report our experience with the transperitoneal laparoscopic removal of stones.MethodRenal pelvic stones of size ≥1 cm on ultrasound were included for laparoscopic pyelolithotomy while smaller stones were managed with shock-wave lithotripsy monotherapy. Intrarenal stones, calyceal stones, complete staghorn stones, multiple stones and kidneys with intrarenal pelvis were excluded. Ureteric stones included for laparoscopic ureterolithotomy were of size ≥1 cm in the upper, mid or lower ureter, and smaller stones not responding to non-operative treatment.ResultsA total of 22 procedures were performed: 12 pyelolithotomies, and 8 lower and 2 upper ureterolithotomies. Complete removal of calculi was accomplished in 21 (95.45%) procedures. Complications associated with laparoscopic lithotomy included urinoma (4.54%), failure (4.54%) and omental prolapse (4.54%).ConclusionLaparoscopic lithotomy is safe and feasible in pediatric urolithiasis with pyelic and ureteric stones, with minimal complications and failure rate.     

Urinary nerve growth factor in children with overactive bladder: A promising,noninvasive and objective biomarker

ObjectiveThis prospective study was designed to determine urinary nerve growth factor (NGF) levels in children with overactive bladder (OAB), and to evaluate whether this factor can be used as a biomarker for diagnosis and monitoring treatment outcome.Patients and methodsUrinary NGF levels were determined in 40 children with OAB and in a control group of 20 children with no urinary symptoms. Urine samples were collected from the patients prior to and at 3 and 6 months after the beginning of treatment. The total NGF levels (pg/mL) were further normalized to the concentration of urinary creatinine (NGF/Cr level).ResultsOverall, both NGF and NGF/Cr levels were significantly higher at the beginning of the study. Mean NGF levels were 30.75 ± 8.35 and 9.75 ± 2.11 pg/ml (p = 0.023) and mean NGF/Cr levels were 0.53 ± 0.14 and 0.16 ± 0.04 (p = 0.022) in patients and controls, respectively. After 6 months of therapy, the NGF/Cr level was significantly reduced to almost control levels (0.16 ± 0.02, p = 0.047).ConclusionNGF and NGF/Cr levels were significantly higher in children with OAB than controls at initial evaluation. Furthermore, the NGF/Cr level was significantly reduced following 6 months of therapy. NGF and NGF/Cr levels show promise as reliable biomarkers for OAB diagnosis and to monitor therapy in the pediatric age group.     

La lithiase urinaire du nourrisson : étude de 14 cas

Background

Diagnosis of urolithiasis in infancy is uncommon. It imposes rational exploration resting on medical history, clinical features, radiologic assessment, metabolic investigation and stone analysis.

Aim

The aim of this study is to evaluate epidemiologic and etiologic features of the urolithiasis in infancy.

Methods

It's a retrospective study including 14 cases of urolithiasis in infants, enrolled in pediatric department of Charles-Nicolle Hospital during fourteen years (1995–2008).

Results

The median age was 13 months. Thirty five percent of the patients had a positive family history of urolithiasis. The main presenting symptoms were urinary tract infection (four cases) and macroscopic hematuria (three cases). Radio-opaque urolithiasis were diagnosed in nine patients (64%), multiple stones in four patients (28%). Six of patients were diagnosed as having metabolic urolithiasis, four anatomic, two infectious and two idiopathic.

Conclusion

In our study, metabolic causes remain the first cause of urolithiasis in infancy.     

Comparison of Pediatric Stone-Formers with and without mutations in Soluable Adenylate Cyclase

PurposeTwo-thirds of children with urolithiasis have hypercalciuria. Recently, a candidate gene for absorptive hypercalciuria (AH) was mapped to chromosome 1q23.3-24 in the adult population. In adults, the presence of up to 6 identified base substitutions in the soluble adenylate cyclase gene (sAC) was associated with a 2.2- to 3.5-fold increased risk for AH. We screened a pediatric population of stone formers for sAC sequence variations.Material and MethodsPediatric patients with stone disease were offered study participation if they met the following criteria: family history of stones; hypercalciuria (urine calcium/creatinine ratio > 0.21 mg/mg creatinine or 24 hour calcium excretion > 4 mg/kg/day); and/or calcium stones on stone analysis. Serum laboratories, spot and 24-hour urine, and bone mineral density (BMD) were collected. Patients were excluded for metabolic conditions predisposing to stone disease. Probands were genotyped for 6 previously identified base substitutions in the sAC gene. Comparisons were made between probands with and without sAC substitutions using Fisher's exact test.ResultsOf 46 children recruited, sAC substitutions were identified in 19 (41%). Clinical parameters were similar in patients with and without substitutions: positive family history in 14/17 (82%) vs. 21/27 (78%); hypercalciuria in 13/19 (68%) vs. 22/27 (82%); and mean number of stone events 2.1 vs. 2.8. Overall, 5/16 (31%) had abnormal BMD (age-adjusted Z-scores < -1.5). More patients with base substitution(s) had abnormal BMD scores (4/9, 44%, vs. 1/7, 14%, p = 0.31), tending towards lower Z-scores (-1.26 vs. -0.3).ConclusionsOf 46 pediatric stone formers, 31% had abnormal BMD scores, and 41% of probands had sAC gene base changes previously identified in adults to increase risk for stones and osteoporosis. This warrants further investigation for potential genetic screening and therapeutic interventions to prevent pediatric stone formation and long-term osteoporotic risk.