Hypercalcemia Secondary to Elevated PTHrP in an Infant Followed by Progression to Nephrotic Syndrome.

In infants, hypercalcemia from elevated parathyroid hormone-related protein (PTHrP) is rare, often signaling neoplasm or renal or urinary anomalies. We report an infant who presented with failure to thrive and hypercalcemia at 10 months old, with initial evaluation showing elevated PTHrP of unclear etiology with imaging negative for neoplasm and no structural anomalies of the kidneys or ureters on ultrasound. Within 6 months of presentation, the patient developed nephrotic syndrome and by 2 years had progressed to end-stage kidney disease, necessitating kidney transplantation. Genetic testing was inconclusive but suggested congenital nephrotic syndrome. While reports of hypercalcemia secondary to elevated PTHrP exist in children with known structural renal anomalies, this is the first to demonstrate hypercalcemia and PTHrP elevation before detection of renal abnormalities. Experimental models have suggested a role for increased PTHrP expression in renal cells following acute kidney injury from nephrotic syndrome, and clinically detectable PTHrP levels may indicate progression of renal injury. We suggest monitoring of renal function for early detection of nephrotic syndrome in infants and children with elevated PTHrP who otherwise lack anatomical renal anomalies or detectable malignancies.

Case report: Unveiling a less severe congenital nephrotic syndrome in a Rapa Nui patient with a NPHS1 Maori founder variant.

Background: Congenital nephrotic syndrome (CNS) is a severe kidney disorder characterized by edema, massive proteinuria, and hypoalbuminemia that manifests in utero or within three months after birth. CNS affects 1-3 per 100,000 children, primarily associated with genetic variants and occasionally with infections. Genetic analysis is the first-line method for diagnosis. The most common founder variants have been identified in European populations, often resulting in end-stage kidney disease by 1-2 years of age. Case-diagnosis/treatment: A female full-term neonate, without prenatal signs of kidney disease, was admitted to Rapa Nui (Eastern Island) Hospital at the age of 2 months due to bronchial obstruction. She presented fever, oliguria, edema, urine protein-to-creatinine ratio (UPCR) 433.33, and hypoalbuminemia (0.9 g/dL). She was transferred to a mainland Chilean hospital following CNS diagnosis. Viral screening detected cytomegalovirus (CMV) positivity in both blood and urine. A kidney biopsy revealed interstitial nephritis and diffuse podocyte damage and the tissue PCR resulted negative for CMV. Interviews with the parents revealed consanguinity, suggestive of hereditary CNS. Genetic analysis identified the Maori founder variant, NPHS1 c.2131C>A (p.R711S), in homozygosis. The patient received albumin infusions and antiviral therapy, being discharged when she was 5 months old, with improved laboratory parameters evidenced by UPCR 28.55, albumin 2.5 g/dL, and cholesterol 190 mg/dL. Subsequent clinical monitoring was conducted through virtual and in-person consultations. At her last follow-up at 4 years 2 months old, she presented UPCR 16.1, albumin 3.3 g/dl and cholesterol 220 mg/dL, maintaining normal kidney function and adequate growth. Conclusions: To our knowledge, this represents the first case of CNS in Chile carrying a NPHS1 variant associated with prolonged kidney survival. As described in the Maori population, the patient exhibited a less severe clinical course compared to classical NPHS1 patients. Genetic testing for the Maori founder variant in CNS patients related to the New Zealand population, could impact management decisions and potentially prevent the need for nephrectomies.

Serological responses to immunization during nephrosis in infants with congenital nephrotic syndrome of the Finnish type.

Background: Pretransplant vaccination is generally recommended to solid organ transplant recipients. In infants with congenital nephrotic syndrome (CNS), the immune response is hypothetically inferior to other patients due to young age and urinary loss of immunoglobulins, but data on the immunization response in severely nephrotic children remain scarce. If effective, however, early immunization of infants with CNS would clinically be advantageous. Methods: We investigated serological vaccine responses in seven children with CNS who were immunized during nephrosis. Antibody responses to measles-mumps-rubella -vaccine (MMR), a pentavalent DTaP-IPV-Hib -vaccine (diphtheria, tetanus, acellular pertussis, inactivated poliovirus, Haemophilus influenzae type b), varicella vaccine, combined hepatitis A and B vaccine, and pneumococcal conjugate vaccine (PCV) were measured after nephrectomy either before or after kidney transplantation. Results: Immunizations were started at a median age of 7 months [interquartile range (IQR) 7-8], with a concurrent median proteinuria of 36,500 mg/L (IQR 30,900-64,250). Bilateral nephrectomy was performed at a median age of 20 months (IQR 14-25), and kidney transplantation 10-88 days after the nephrectomy. Antibody levels were measured at median 18 months (IQR 6-23) after immunization. Protective antibody levels were detected in all examined children for hepatitis B (5/5), Clostridium tetani (7/7), rubella virus (2/2), and mumps virus (1/1); in 5/6 children for varicella; in 4/6 for poliovirus and vaccine-type pneumococcal serotypes; in 4/7 for Haemophilus influenzae type B and Corynebacterium diphtheriae; in 1/2 for measles virus; and in 2/5 for hepatitis A. None of the seven children had protective IgG levels against Bordetella pertussis. Conclusion: Immunization during severe congenital proteinuria resulted in variable serological responses, with both vaccine- and patient-related differences. Nephrosis appears not to be a barrier to successful immunization.

Managing venous thrombosis in a pediatric patient with short bowel and congenital nephrotic syndromes: a case report emphasizing rivaroxaban level monitoring.

Direct Oral Anticoagulants (DOACs) typically exhibit a predictable pharmacokinetic and pharmacodynamic response at a fixed dose, not necessitating monitoring under standard conditions. Yet, in specific clinical scenarios that can impair it, like Congenital Nephrotic Syndrome (CNS) or Short Bowel Syndrome (SBS) due to absorption issues, anti-thrombin III (AT-III) deficiency and non-selective proteinuria, adjusting the dosage to achieve appropriate plasma concentrations could prove beneficial. We report a 3-month-old female with catheter-related jugular thrombosis affected by CNS concomitant to SBS and failure of both treatments with heparin and warfarin, that was switched to dose-adjusted pediatric rivaroxaban. Rivaroxaban was adjusted to reach peak levels between 189 and 419 ng/ml and the lower trough levels between 6 and 87 ng/ml. Increasing doses were needed due to SBS related malabsorption but a complete permeabilization of the vein was achieved without bleeding complications. The use of anti-Xa adjusted rivaroxaban could be an alternative to improve anticoagulation and secondary thromboprophylaxis in pediatric patients SBS and an option to children with CNS.

New insights from the genetic work-up in early onset nephrotic syndrome: report from a registry in western India.

BACKGROUND: Eighty-five percent of infants with congenital nephrotic syndrome (CNS) and 66% with infantile NS (INS) are likely to have a monogenic etiology. There exists a significant genetic variability between different regions and ethnic groups. This study aimed to determine the genetic defects in children with CNS and INS by establishing a registry in western India. METHODS: In this cross-sectional study, pediatric nephrologists from 13 private and government institutions shared relevant clinical data and details of the genetic evaluation of children presenting with NS within the first year of life. RESULTS: The median age at presentation was 9 months (range 1-23, IQR 3-13 months), history of consanguinity between parents existed in 14 patients (34%), family history of similar illness in 6 (15%), and extra-renal manifestations in 17 (41%). Twenty-five (61%) were confirmed to have a monogenic etiology. NPHS1 gene was the most implicated (9/25) followed by PLCE1 (5/25). There were 12 variants of uncertain significance (VUS) involving 10 genes (10/25, 40%), and no definite genetic abnormality was found in 4 (25%). A re-analysis of these VUS attempted 2-3 years later facilitated reclassification of 7/12 (58%); increasing the diagnostic yield from 61 to 68.2%. CONCLUSIONS: Consistent with worldwide data, variants in NPHS1 gene were the most common cause of NS in infancy; however, PLCE1 was implicated more frequently in our cohort. NUP93 and COL4A3 were reported in early onset NS for the first time. Reclassification of VUS should be attempted, if feasible, since it may lead to a useful revision of diagnosis.

Congenital nephrotic syndrome with diffuse mesangial sclerosis caused by compound heterozygous mutation in LAMA5 gene.

A two-and-a-half-month-old female infant presented with generalized edema for 10 days. At presentation, she had periorbital puffiness, moderate ascites, and pedal edema. Laboratory investigations revealed serum albumin 1.3 g/dL, spot urine protein to creatinine ratio (Up:Uc) 20.87 mg/mg, total cholesterol 380 mg/dL, and serum creatinine 0.31 mg/dL. Exome sequencing revealed compound heterozygous variants in LAMA5 gene (NM_005560.6). There was a heterozygous likely pathogenic missense variant in exon 2: LAMA5: c.385C > A (depth 195 ×) and another heterozygous pathogenic variant in exon 31: LAMA5: c.3932_3936dup; parental segregation by Sanger sequencing proved that the variants were in trans. Kidney biopsy showed diffuse mesangial sclerosis (DMS). Our case adds LAMA5 gene to the constellation of genes causing DMS, in addition to the classically described WT1, LAMB2, and PLCE1 genes and to the list of genes causing congenital nephrotic syndrome (CNS).

LAMB2 gene: broad clinical spectrum in Pierson syndrome.

Pierson syndrome (PS) is a rare autosomal recessive disease, characterized by congenital nephrotic syndrome (CNS), and ocular and neurologic abnormalities. In affected cases, there is abnormal b-2 laminin which is compound of the several basement membranes caused by inherited mutations in the LAMB2 gene. Although patients have mutations in the same gene, the phenotype is highly variable. In this case series, the relationship between genotype and phenotype is emphasized, and information about the clinical follow-up of the patients is presented. Hereby, we report four pediatric cases with PS as a result of mutation in the LAMB2 gene. Clinical spectrum of LAMB2-associated disorders varies from mild-to-severe ocular, kidney, and neurologic involvement. Since genotype-phenotype correlation in PS has not been clearly demonstrated, we recommend that all patients with ophthalmic anomalies and glomerular proteinuria should be tested for LAMB2 mutations.

[Congenital Nephrotic Syndrome: Role of Podxl Gene].

In the last decades, our understanding of the genetic disorders of inherited podocytopathies has advanced immensely; this has been possible thanks to the development of next-generation sequencing technologies that offer the possibility to evaluate targeted genes at a lower cost than in the past. Identifying new genetic mutations has helped to recognize the key role of the podocyte in the health of the glomerular filter and to understand the mechanisms that regulate the cell biology and pathology of the podocyte. Here we describe a patient with congenital nephrotic syndrome due to a mutation in PODXL. This gene encodes podocalyxin, a podocyte-specific surface sialomucin known to maintain the characteristic architecture of the foot processes and the patency of the filtration slits.

Systematic Review of Clinical Characteristics and Genotype-Phenotype Correlation in LAMB2-Associated Disease.

Introduction: Laminin subunit beta-2 (LAMB2)-associated disease, termed Pierson syndrome, presents with congenital nephrotic syndrome, ocular symptoms, and neuromuscular symptoms. In recent years, however, the widespread use of next-generation sequencing (NGS) has helped to discover a variety of phenotypes associated with this disease. Therefore, we conducted this systematic review. Methods: A literature search of patients with LAMB2 variants was conducted, and 110 patients were investigated, including 12 of our patients. For genotype-phenotype correlation analyses, the extracted data were investigated for pathogenic variant types, the severity of nephropathy, and extrarenal symptoms. Survival analyses were also performed for the onset age of end-stage kidney disease (ESKD). Results: Among all patients, 81 (78%) presented with congenital nephrotic syndrome, and 52 (55%) developed ESKD within 12 months. The median age at ESKD onset was 6.0 months. Kidney survival analysis showed that patients with biallelic truncating variants had a significantly earlier progression to ESKD than those with other variants (median age 1.2 months vs. 60.0 months, P < 0.05). Although the laminin N-terminal domain is functionally important in laminin proteins, and variants in the laminin N-terminal domain are said to result in a severe kidney phenotype such as earlier onset age and worse prognosis, there were no significant differences in onset age of nephropathy and progression to ESKD between patients with nontruncating variants located in the laminin N-terminal domain and those with variants located outside this domain. Conclusion: This study revealed a diversity of LAMB2-associated diseases, characteristics of LAMB2 nephropathy, and genotype-phenotype correlations.

Usefulness of Early Genetic Diagnosis for Twins With a Family History of Congenital Nephrotic Syndrome.

We reported a dichorionic diamniotic placental twin (DD twin) with a family history of a congenital nephrotic syndrome of the Finnish type (CNF), of which the parent had heterozygous for the NPHS1 gene mutation. The DD twin was born at 36 weeks gestation, and their fused placenta weighed 1,340 g. Although the first-born child had heavy proteinuria and hypoalbuminemia and needed daily albumin replacement to manage severe edema, the second had only mild proteinuria after birth. Genetic testing performed 28 days after birth detected homozygous for the NPHS1 gene mutation in only the first-born child but not in the second, which resulted in performing invasive left nephrectomy and peritoneal dialysis (PD) to manage edema in the first. For DD twins with a family history of CNF, prenatal diagnosis of CNF may be difficult. Therefore, close postnatal clinical observation and early genetic testing are essential for the diagnosis of CNF.

Infantile Galactosialidosis with Novel Mutation: An Early Presentation.

Galactosialidosis (GS) is a rare lysosomal storage disorder. We reported here, the case of a 29-day-old boy who had increased body swelling, difficulty breathing, and petechiae on the trunk since birth. The antenatal history was unremarkable. Clinical laboratory findings included coarse facies, hepatosplenomegaly, gross ascites, thrombocytopenia, nephrotic range proteinuria, and bilateral hydronephrosis. The diagnostic challenge was resolved after genetic testing, which revealed GS with a novel homozygous c.1158dupA mutation.

Congenital adrenal calcifications as the first clinical indication of sphingosine lyase insufficiency syndrome: A case report and review of the literature.

Sphingosine Lyase Insufficiency Syndrome (SPLIS) or SGPL1 Deficiency is a newly described entity that is characterized by steroid-resistant nephrotic syndrome, primary adrenal insufficiency, lymphopenia, ichthyosis, and/or endocrine and neurologic abnormalities. The earliest identification of SGPL1 pathogenic variants in association with this syndrome was reported in 2017. Since then, at least 36 patients have been reported with this pediatric syndrome. Here, we report a new patient with SPLIS who had a prenatal finding of adrenal calcifications, congenital nephrotic syndrome, and abnormal newborn screening concerning for Severe Combined Immunodeficiency. We conclude that SPLIS is a clinically recognizable condition with prenatal onset. This case should increase awareness of SPLIS in the differential diagnosis for adrenal calcifications. We present a case on the severe end of the clinical spectrum of SPLIS, and a review of the literature.

Spectrum of Clinical Manifestations in Children With WT1 Mutation: Case Series and Literature Review.

Background: Mutations of the Wilms tumor suppressor-1 gene (WT1) are associated with life-threatening glomerulopathy, disorders of sexual development, Wilm's tumor, and gonadal malignancies. Our objectives were to describe the clinical presentations, age of progression, and onset of complications of WT1 mutation through a case series and literature review. Methods: A retrospective study included all patients followed at the University of Miami/Holtz Children's Hospital from January 2000 to December 2020 with a diagnosis of WT1 mutation. A literature review of WT1 mutation cases was analyzed for clinical manifestations, karyotype, and long-term outcomes. Results: The WT1 mutation was identified in 9 children, median age at presentation of 0.9 years (range 1 week to 7 years). A total of four had female phenotypes, and 5 had abnormalities of male external genitalia, while all had XY karyotypes. All progressed to end-stage kidney disease (ESKD) and received a kidney transplant at a median age of 5 years (1.5-15 years). During a median time of follow-up of 9 years (range 2-28 years), there were 2 allograft losses after 7 and 10 years and no evidence of post-transplant malignancy. From 333 cases identified from the literature review, the majority had female phenotype 66% (219/333), but the predominant karyotype was XY (55%, 183/333). Of the female phenotypes, 32% (69/219) had XY sex reversal. Wilm's tumor occurred in 24%, predominantly in males with gonadal anomalies. Conclusions: Early recognition of WT1 mutation is essential for comprehensive surveillance of potential malignancy, avoidance of immunosuppressants for glomerulopathy, and establishing long-term multidisciplinary management.

Hemodialysis-Related Vision Loss from Anterior Ischemic Optic Neuropathy.

Vision loss from nonarteritic anterior ischemic optic neuropathy (NAION) is a rare complication of hemodialysis. Here, we present a case in a young woman and discuss the pathophysiology and implications for the nephrologist. A 24-year-old woman with end-stage renal disease developed unilateral, painless vision loss following treatment with hemodialysis. Fundoscopy revealed severe left inferior chalky-white opticdisc edema, a presentation consistent with NAION. Her intradialytic blood pressure was reviewed and found to be significantly lower than her baseline, and a multidisciplinary meeting took place between her ophthalmologist and nephrologist to modify her dialysis sessions to minimize the chance of progression or involvement of her fellow eye. At the 2-month follow-up, the opticdisc edema resolved, and her visual function remained stable. Overall, NAION is a rare complication of hemodialysis and may be a result of intradialytic hypotension, platelet and endothelial dysfunction, anemia, and accumulations of toxins such as urea. As there are no established treatments for NAION, management should focus on optimizing modifiable risk factors to prevent further vision loss in the other eye. These factors include increasing the number of dialysis sessions and duration of sessions, reducing the temperature of the dialysate, discouraging eating, and increasing the dialysate's calcium concentration. Prompt recognition of NAION and multidisciplinary teamwork can minimize the risk of NAION progression and involvement of the contralateral eye.

Congenital Nephrotic Syndrome of the Finnish Type in a Dominican Newborn: An Overview and Case Report.

Congenital nephrotic syndrome of the Finnish type (CNS-FT) is a rare genetic condition that causes massive proteinuria, hypoproteinemia, hypercholesterolemia, and edema that progresses to end-stage renal disease. Symptoms may manifest in utero as fetal hydrops or during the first few days to months of life. This article shares the case of a Dominican infant who presented with CNS-FT. It provides a comprehensive overview of CNS-FT including the underlying genetic cause, prenatal and postnatal diagnostic testing options, and treatment recommendations. It walks the reader through the diagnostic and initial and longer-term management of this infant and provides patient outcome at 10 months of age.

Unilateral nephrectomy for young infants with congenital nephrotic syndrome of the Finnish type.

BACKGROUND: The management of congenital nephrotic syndrome of the Finnish type (CNF) is challenging. It is difficult to withdraw intravenous albumin infusions, resulting in long-term hospitalization. In addition, fatal hypotension after bilateral nephrectomy has been reported. In our center, we have performed unilateral nephrectomy during early infancy. METHODS: Infants diagnosed with CNF between 2011 and 2020 in our institution were enrolled. We examined the clinical course before and after unilateral nephrectomy and evaluated the effectiveness of this strategy. RESULTS: Seven patients (all showing NPHS1 mutations) were enrolled. All required daily intravenous albumin infusion via central venous catheter (CVC). Unilateral nephrectomy was performed at a median of 76 days of age (59-208 days). Surgical complications did not occur in any of patients. The mean albumin dose was decreased after unilateral nephrectomy (2.0 vs 0.4 g/kg/day; p = 0.02). Intravenous albumin infusion could be withdrawn at a median of 17 days, the CVC removed at a median of 21 days, and they discharged at a median of 82 days after unilateral nephrectomy. Although bacterial infections were noted seven times before unilateral nephrectomy, only one episode occurred after surgery. Four patients initiated peritoneal dialysis at two to three years of age and all of them underwent kidney transplantation thereafter. CONCLUSIONS: Unilateral nephrectomy during early infancy may be an effective treatment allowing for withdrawal from albumin infusion, prevention of complications, withdrawal from CVCs and shortening hospital stay for patients with CNF.

Skimmed breast milk for treatment of hypertriglyceridemia in an infant with congenital nephrotic syndrome.

Congenital nephrotic syndrome (CNS) is a complex condition that requires multidisciplinary care. Hyperlipidemia is a characteristic feature with elevation of serum cholesterol and triglycerides. Little evidence is available to guide treatment of dyslipidemia in infants with CNS. We describe successful treatment of severe hypertriglyceridemia through dietary changes in a boy with CNS. A 9-day-old boy presented to the emergency department with lower extremity edema caused by deep venous thrombosis. Laboratory evaluation identified hypoalbuminemia, nephrotic-range proteinuria, and a pathogenic variant of the NPHS1 gene. The initial triglyceride concentration of 369 mg/dl increased to 3096 mg/dl by 5 weeks of age, when his diet consisted of breast milk. Refrigerated breast milk was skimmed by removing the top layer after allowing it to separate for 24 h. This process was repeated prior to use. Skimmed breast milk was supplemented with medium-chain triglyceride oil and an infant protein powder. After 2 days, the triglyceride concentration declined to 481 mg/dl and, by day 10, to 148 mg/dl. When breast milk supply decreased, a 1:1 ratio of skimmed maternal breast milk to an elemental, very low-fat formula was utilized. The triglyceride concentration remained below 400 mg/dl for the first year of life, except when skimmed breast milk was not available during hospitalization. Severe hypertriglyceridemia caused by CNS can present in the neonatal period and be difficult to manage. In our patient, skimmed maternal breast milk was successful in reducing the triglyceride concentration and should be considered a therapeutic option for children with hyperlipidemia caused by CNS.

Congenital nephrotic syndrome in a Hispanic Guatemalan newborn associated with a NPHS1 variant: A case report.

Congenital nephrotic syndrome (CNS) is an autosomal recessive disorder usually detected in the first 3 months of life when the syndromes effects manifest, including edema and a failure to gain weight. A baby boy was admitted to the Neonatal Intensive Care Unit for prematurity (35 weeks) with unremarkable maternal prenatal laboratory tests. The patient had persistent systemic hypertension, hypoproteinemia, hypoalbuminemia and nephrotic range proteinuria. CNS was diagnosed, and genetic testing showed a homozygous variant, c.3024A>G (AGA>AGG) in exon 22 of the nephrin locus. Bioinformatics analysis suggested the genetic condition was likely a result of malfunctional DNA binding sites of transcription factors FOXL1 and FOXC1.