Untargeted Maternal Plasma Metabolomics in Hirschsprung Disease: A Pilot Study

Background and Aims

Hirschsprung disease (HSCR) is a congenital disorder of unknown etiology affecting the enteric nervous system (ENS). Since the early gestational development of the ENS is dependent on the prenatal maternal metabolic environment, the objective of this pilot study was to explore the role of specific maternal plasma metabolites in the etiology of HSCR.

Methods

In this cross-sectional study, postnatal (as a surrogate for prenatal) plasma samples were obtained from mothers of children diagnosed with HSCR (n = 7) and age-matched mothers of normal children (n = 6). The plasma metabolome was analyzed by ultra-high-pressure liquid chromatography and mass spectrometry. Metabolites were identified by mzCloud using Compound Discoverer software. Using an untargeted metabolomics workflow, metabolites with case versus control group differences were identified.

Results

A total of 268 unique plasma metabolites were identified and annotated in maternal plasma. Of these, 57 were significantly different between case and control groups (P < 0.05, t-test). Using a false discovery rate corrected cutoff of 10% to adjust for multiple comparisons, 19 metabolites were significantly different in HSCR cases, including carnitines, medium-chain fatty acids, and glutamic acid. Pathways affected were for amino acid and lipid metabolism.

Conclusion

Disordered prenatal metabolic pathways may be involved in the etiopathogenesis of HSCR in the developing fetus. This is the first study to assess maternal plasma metabolomics in HSCR.

Maternal Vitamin A Status as a Risk Factor of Hirschsprung Disease in the Child

INTRODUCTION

The gene-environment interaction of the REarranged during Transfection ( RET ) gene with vitamin A in the etiopathogenesis of Hirschsprung disease (HSCR) has been suggested in rodents. The aim of this study was to evaluate vitamin A status in mothers of children with HSCR and to assess its association with pathogenic variants of the RET gene in affected children.

METHODS

This was a case-control study of stable isotope-based vitamin A measurement stores of mothers of children diagnosed with HSCR (within 8 months from birth, n = 7) and age-matched mothers of normal children (n = 6). Next-generation sequencing of RET exons, along with their upstream promoter region, was performed in the 7 HSCR proband-parent triads to evaluate pathogenic variants.

RESULTS

Maternal vitamin A stores in the HSCR group was almost 50% that of those in controls, tending toward significance (0.50 ± 0.17 vs 0.89 ± 0.51 μmol/g respectively, P = 0.079). Two novel pathogenic de novo mutations were identified in 2 cases, and a rare single-nucleotide deletion was detected in the 3.5-kb RET upstream region, in a heterozygous state, in all 7 proband-parent triads. Low-penetrance RET haplotypes associated with HSCR were detected in 5 cases.

DISCUSSION

Mothers with children with HSCR had lower vitamin A liver stores than mothers with normal children, and the children who were affected had HSCR despite having no established pathogenic RET variants. Lower maternal vitamin A status may increase the penetrance of genetic mutations in RET , and vitamin-A mediated gene-environment interactions may underpin some of the etiology of HSCR.

46 XY disorder of sex development (DSD) due to 5 alpha (SRD5A2) deficiency - Experience from a multidisciplinary Pediatric Gender Clinic

BACKGROUND

SRD5A2 deficiency leads to incomplete masculinization of individuals with a 46 XY karyotype. A definitive diagnosis in early infancy facilitates decisions concerning choice of sex of rearing and management.

AIM

To review the clinical presentation, diagnosis, treatment and outcome of children with 46 XY DSD due to SRD5A2 deficiency at a Paediatric Gender Clinic.

STUDY DESIGN AND METHODS

Retrospective review of cases of SRD5A2 deficiency (2000-15) managed with a standard protocol at a multidisciplinary clinic. Demographic data, clinical presentation, physical findings, investigations (hormonal profile, imaging, genitoscopy), psychological evaluation (child, family), medical and surgical management, outcome and follow up were collated and analyzed.

RESULTS

There were 12 cases aged 3 days-14 years at presentation, 3 had parental consanguinity. Eight were reared as males and 4 as females. Specialist referral was sought for hypospadias (5), atypical genitalia (5) or incongruent pubertal masculinization (2). All had chordee, symmetrical inguinoscrotal gonads, rugose labioscrotum and proximal hypospadias (perineoscrotal -9, perineal -3). Both pubertal cases had significant masculinization and no gynecomastia. The median testosterone/dihydrotestosterone ratio was 22.1(IQR-8.6-55.7). Despite a classical phenotype, four (2 prepubertal, 2 pubertal) had a ratio <10. Genitoscopy showed urogenital sinus remnant (4) and hypoplastic verumontanum (5). Sex reassignment was done in 4. Surgical management was staged and completed by 4 years in those with infantile presentation. Besides correction of chordee and urethroplasty in 11, other procedures included orchidopexy (5), excision of a urogenital sinus remnant (4) and correction of penoscrotal transposition (4). The urethroplasty was single staged in 3. All operated cases were followed up (mean age at last follow up - 10.63 years, mean follow up period - 7.25 years). The overall cosmetic result was satisfactory, but the phallic structure remained relatively small across prepubertal period. Uroflowmetry curves were normal in 9. All showed penile tumescence/erection and two peripubertal cases had typical secondary sexual characters. All cases, including those with sex reassignment, have a well-adjusted male psyche.

DISCUSSION AND CONCLUSION

The diagnosis, management and longitudinal follow up of cases of SRD5A2 deficiency at a multidisciplinary gender clinic is presented. Diagnostic dilemmas with low T/DHT ratios remained in a third of cases. Most were diagnosed in infancy and assigned a male sex of rearing, all underwent staged masculinizing genitoplasty. Those with sex reassignment also fared well with comprehensive management after family counseling.

Recurrent pneumonia owing to migratory peanut foreign body

Accidental foreign body aspiration in children is a leading cause of childhood morbidity. Prompt recognition and timely management reduce complications, some of which are potentially fatal. A previously well 2-year-old girl presented with recurrent episodes of cough, fever and tachypnoea with chest indrawing for the previous 7 months. The first episode lasted almost 4 weeks. There was no history of choking. She was underweight (Z-score -2 to -3) with initially normal height. The chest radiograph demonstrated opacities in the left lung first, but subsequently there were lesions in both lungs. Computerised tomography confirmed the chest radiograph findings. Bronchoscopy demonstrated pus and granulomatous tissue in the left main bronchus, but no foreign body was detected and she was treated with antibiotics. Over the following 18 months she had several outpatient and four inpatient treatments for the same complaint. There was progressive weight loss, stunting and she developed finger clubbing. During her fourth admission, a repeat bronchoscopy again demonstrated granulomatous tissue with pus in the left main bronchus and remnants of a migratory peanut and signs of early bronchiectasis. Following removal of the peanut, her health began to recover, and, at follow-up a year later, her chest radiograph was normal, her growth had caught up and she was in normal health.

Risk factors for renal scarring and clinical morbidity in children with high-grade and low-grade primary vesicoureteral reflux

INTRODUCTION

Primary vesicoureteral reflux (VUR) is associated with urinary tract infections (UTIs) and renal damage. However, the importance of early diagnosis of VUR has been questioned. Moreover, most studies have few patients with high-grade VUR. Hence, we retrospectively analyzed a large cohort of patients with primary high-grade and low-grade VUR and assessed risk factors for renal damage and clinical morbidity.

MATERIAL AND METHODS

We included patients (<18 years) at diagnosis with low-grade (1-3) or high-grade (4-5) primary VUR and noted their clinical history and presence of hypertension, low eGFR (<60ml/in/1.73 m²), renal scarring (focal or generalised) and reduced differential renal function (DRF; <45%). Risk factors were assessed (in patients and renal units) by logistic regression and generalised estimating equation.

RESULTS

Of 399 primary VUR patients, 255 (64%) had high-grade VUR. Indications for voiding cystourethrogram were recurrent UTI (38%), first UTI (28%) and antenatal hydronephrosis (17%). At diagnosis, 252 (65%) had renal scars (focal in 170 [44%], generalised in 82 [21%]), and 188 (47%) had reduced DRF. High-grade VUR patients were more likely than low-grade VUR patients to have renal scarring (75% vs. 49%, p < 0.01), low eGFR (23% vs. 13%, p = 0.04) and significant hypertension (26% vs. 13%, p = 0.02). High-grade VUR was associated with generalised scars (odds ratio [OR] 11, p < 0.001), focal scars (OR 3.1, p < 0.001) and reduced DRF (OR 2.3, p < 0.001) shown in the table. Male sex was a risk factor for generalised scars (OR 2.3, p = 0.005). Focal scars were associated with recurrent UTIs (OR = 1.8, p = 0.004) and reduced DRF (OR 1.4, p = 0.027). Patients with multiple focal scars were diagnosed at an older age (2 years [1,4] than those with single scars (1.5 years [1,4] or no scars (1 year [0, 3]), p = 0.04).

DISCUSSION

The prevalence of renal damage and clinical morbidity at VUR diagnosis was higher than other studies. High-grade VUR patients had a greater prevalence of renal damage, low eGFR and hypertension than low-grade VUR patients and was a risk factor for focal scars, generalised scars and reduced DRF. Focal scars were independently associated with recurrent UTI. Those with multiple scars were diagnosed later than those with single scars or no scars.

CONCLUSIONS

High-grade VUR was associated with renal damage and clinical morbidity. Our study highlights the importance of diagnosing VUR early to identify patients who may warrant long-term follow-up and intervention to minimize morbidity.

Distal ureteral atresia – an embryological dilemma

Introduction:

Distal ureteral atresia is a rare urinary tract anomaly generally associated with ipsilateral renal dysplasia and abnormalities such as multicystic dysplastic kidney, hydronephrosis and megaureter in the contralateral kidney. Despite burgeoning investigation modalities, definitive preoperative diagnosis of this condition is rarely feasible, also the embryological disarray of events that result in the development of this anomaly and the associated malformations is not clearly understood.

Case presentation:

We hereby report two cases of distal ureteral atresia and discuss the diversity in their presentations, diagnosis, atypical associations and management and review the possible embryological mal-development.

Conclusion:

Distal ureteral atresia with urogenital sinus as in Case 1 has not been documented so far and a plausible embryological explanation is deduced regarding its occurrence. The course of the affected kidney following timely and adequate relief of obstruction in Case 2 is depicted, highlighting the eventual management.

Level of evidence:

Not applicable

Deciphering the mutation spectrum in south Indian children with congenital anomalies of the kidney and urinary tract

BACKGROUND

Congenital anomalies of the kidney and urinary tract (CAKUT) cover a spectrum of structural malformations that result from aberrant morphogenesis of kidney and urinary tract. It is the most prevalent cause of kidney failure in children. Hence, it is important from a clinical perspective to unravel the molecular etiology of kidney and urinary tract malformations. Causal variants in genes that direct various stages of development of kidney and urinary tract in fetal life have been identified in 5-20% of CAKUT patients from Western countries. Recent advances in next generation sequencing technology and decreasing cost offer the opportunity to characterize the genetic profile of CAKUT in Indian population and facilitate integration of genetic diagnostics in care of children with CAKUT.

METHODS

Customized targeted panel sequencing was performed to identify pathogenic variants in 31 genes known to cause human CAKUT in 69 south Indian children with CAKUT. The NGS data was filtered using standardized pipeline and the variants were classified using ACMG criteria. Genotype and phenotype correlations were performed.

RESULTS

The cohort consisted of children mostly with posterior urethral valve (PUV) (39.1%), vesico-ureteric reflux (VUR) (33.3%) and multi-cystic dysplastic kidney (MCDK) (7.2%). No pathogenic or likely pathogenic variants were identified in the study. Most of our variants (n = 39, 60%) were variants of unknown significance with 25.6% (10/39) of them were identified as potentially damaging but were novel variants.

CONCLUSIONS

The present study did not identify any disease-causing monogenic variants in the cohort. The absence of genetic cause may be due to limitations of panel-based testing and also due to higher proportion of children with abnormalities in lower urinary tract than hypodysplasia of kidneys. Clinical, larger targeted panel or whole exome sequencing may be a better method to characterize the genetic profile of Indians patients with CAKUT.

Antenatal urolithiasis: A case report

INTRODUCTION

Although pediatric urolithiasis is an established entity, its antenatal diagnosis is rare. We hereby report a case detected at 20 weeks gestation and discuss the etiopathogenesis, predisposition, and surveillance following intervention.

CASE REPORT

A 2-year-old girl with left renal pelvic calculus detected antenatally at 20 weeks was evaluated. Left hydronephrosis, obstructive pelvic calculus with a decrease in differential renal function on ethylene dicysteine (EC) renogram was confirmed. The metabolic workup was normal. Following stone extraction by left pyelolithotomy, a left ureteropelvic junction obstruction secondary to a mucosal valve was apparent which was excised and left pyeloplasty was done. Stone analysis revealed 100% cystine. Differential renal function and drainage improved post-surgery. The child, however, did not have a follow-up in the interim and presented with a recurrent stone one and a half years later.

CONCLUSION

Knowledge of antenatal urolithiasis ensures continued follow-up, evaluation for metabolic disorders, and associated structural defects, especially with increasing stone size and increasing hydronephrosis. This helps in timely intervention and continued surveillance.

Pelviureteric Junction Obstruction Due to Vascular Anomalies in Children - Simple Surgical Options

Aims

Pelviureteric junction obstruction (PUJO) due to aberrant lower polar artery is conventionally managed with pyeloplasty. We present our experience of managing PUJO due to "vascular" anomalies-aberrant lower polar artery and vascular adhesions with simpler surgical options.

Subjects and Methods

This is a protocol based, retrospective study of PUJO. Preoperative investigations included ultrasonography (USG) and diuretic renogram. An intraoperative methylene blue test (MBT) assessed transit across the Pelviureteric junction (PUJ) after release of vascular compression. Surgical management included adhesiolysis for vascular adhesions and pyelopyelostomy anterior to the aberrant polar artery. Postoperative studies were repeated after 3 and 6 months.

Results

Fourteen of 144 PUJO (9.7%) were "vascular" obstructions. Those with vascular adhesions (six) were largely infants with antenatal hydronephrosis. Children with aberrant lower polar artery (eight) were older, had fleeting symptoms, minimally increased pelvic diameter and subtle impairment on diuretic renogram. Majority were term males with urinary tract infection. The MBT showed normal transit across the PUJ in all. Postoperatively, there was progressive improvement on USG and diuretic renogram after 3 and 6 months. None had any complication or redosurgeries. At a mean follow-up of 41.2 months, all are asymptomatic.

Conclusions

PUJO due to extrinsic vascular anomalies is rare. Intraoperative evaluation with the MBT ruled out associated intrinsic pathology. We describe two simple surgical alternatives preserving the normal PUJ - adhesiolysis for vascular adhesions and pyelopyelostomy for aberrant lower polar artery. The preliminary outcomes are comparable to conventional pyeloplasty.

Effects of oxybutynin in children with posterior urethral valves post fulguration: Report in a select cohort of children

Objectives:

Posterior urethral valves (PUV) is the commonest obstructive uropathy with varied consequences. Though valve fulguration is the treatment of choice, appropriate bladder management modifies outcome and includes rational use of anticholinergics. Here, we aim to evaluate the effects of oxybutynin on the bladder and urinary tract morphology and function. Concurrently, we document adverse effects encountered, patient compliance, and medication adherence.

Methods:

A retrospective study of children below 5 years of age (2012–2017) post fulguration and on oxybutynin for at least 6 months. Patient demographics, clinical features, renal ultrasound, micturating cystourethrogram, dimercaptosuccinic acid scan, adverse effects, and pill count for medication adherence were collated.

Results:

48 children below the age of 5 years were included, and 12 were excluded either due to the presence of concomitant problems or were not on oxybutynin. Of the 36, four were lost to follow-up and one had died due to an unrelated condition. Thus, a total of 31 children were analyzed. At follow-up, 28/31 patients were asymptomatic, two had daytime incontinence, and one had recurrent urinary tract infection. All patients except one have preserved renal function tests. On ultrasonography, hydroureteronephrosis worsened in only 1/25 children and two showed significant post void residues. The resolution of vesicoureteral reflux was noted in almost 50%. 4/31 renal units had progressive scars. Only two parents defaulted medication. Urodynamic study done in half of these children showed stable bladder pressures except in two.

Conclusion:

Oxybutynin therapy following adequate valve fulguration aids upper tracts preservation by stabilizing deranged bladder dynamics. The medication is well tolerated with minimal or no side effects.

Multiple Atypical Esophageal Foreign Bodies in an Infant

Foreign body ingestion is a common accidental emergency in children. We report an unusual case of multiple blunt and sharp esophageal foreign bodies in a female infant probably associated with homicidal intent and its management.

Dextrogastria and Malrotation of Midgut in a Neonate

A neonate presented with bilious vomiting and hematochezia. The infantogram and upper gastrointestinal contrast study were suggestive of dextrogastria with malrotation of midgut. Laparotomy confirmed isolated dextrogastria, malrotation of the midgut and volvulus. Reverse Ladd’s procedure was done.

Retaining the refluxing lower ureteral stump of a non-functioning kidney to preserve contralateral renal function

BACKGROUND

It is crucial to preserve the renal parenchyma in a solitary renoureteric system, especially when associated with VUR and/or elevated bladder pressures.

AIM

The present study examined the effect of retaining the refluxing lower ureteral stump of a non-functioning renal unit (during nephrectomy) as a stoma to preserve contralateral renal function.

STUDY DESIGN

Twelve children with various uropathologies (six with PUV, three with primary VUR, and three with neurogenic bladder) and a solitary functioning kidney were retrospectively analysed. In each, besides the relevant investigations and specific management, nephrectomy was performed for a non-functioning kidney with recurrent UTI (10/12) or hypertension (2/12), and the ipsilateral distal ureteric stump was exteriorised as a refluxing stoma. Antimicrobial prophylaxis was given to those with VUR into the solitary kidney (9/12). All were on strict follow-up at a dedicated paediatric nephrourology clinic with serial clinical, biochemical and radiological surveillance.

RESULTS

The mean age at presentation and surgery was 19.7 months (range 0.5-96) and 30.5 months (range 3-100), respectively. Recurrent UTI (10/12) and acute renal failure (8/12) were common presentations; 2/12 were hypertensive. The initial serum creatinine ranged from 0.3 to 7.2 (mean 2.3) mg/dl. Of the solitary functioning kidneys with VUR (9/12), seven had Grade 5 VUR and six had renal cortical scars. The stoma served as an intermittent vent (9/12), for CIC (4/12) or for both purposes (3/12). Although all were Grade 5 refluxing ureters, 3/12 stomas remained dry. At a mean follow-up of 30 months (12-48), 9/12 were well and 3/12 were in end-stage renal disease. None had a UTI after the procedure. VUR resolved in five ureters that sub-served the contralateral solitary kidney. Serial DMSA renal cortical scans showed no scarring in four children, non-progressive scars in three and new scars in two. At the last follow-up, four (one dry, three leaking) were being used for CIC, four (one dry, three leaking) had been closed and four (one dry, three leaking) were retained until resolution of contralateral reflux/non-progression of scarring (three) or for possible CIC in the future (one).

DISCUSSION AND CONCLUSION

Retaining the refluxing lower ureteral stump of a non-functioning kidney as a cutaneous stoma provided a vent and an alternative channel for CIC of the bladder (Figure). Subsequently, fewer UTI seemed to protect the contralateral solitary functioning kidney, particularly in those with associated VUR. In this preliminary study, the procedure was simple and the stoma was well accepted by patients and parents.