Symptomatic renal papillary varicosities and medullary nephrocalcinosis

Background Nephrocalcinosis is often asymptomatic but can manifest with renal colic or hematuria. There is no reported association between nephrocalcinosis and renal vascular malformations, which may also be a source of hematuria. We herein present a case of a patient with hematuria related to nephrocalcinosis and renal papillary varicosities. These varicosities were diagnosed and successfully treated with flexible ureteroscopy and laser fulguration. Case presentation A 24-year-old female with a history of epilepsy (on zonisamide), recent uncomplicated pregnancy, and new diagnosis of nephrocalcinosis presented with right flank pain and intermittent gross hematuria. Imaging revealed intermittent right sided hydronephrosis. A cystoscopy identified hematuria from the right ureteral orifice. Diagnostic flexible ureteroscopy revealed numerous intrapapillary renal stones and varicose veins of several renal papillae. A 200 μm holmium laser fiber was used to unroof these stones and fulgurate the varicosities with resolution of her symptoms for several months. She later presented with left-sided symptoms and underwent left ureteroscopy with similar findings and identical successful treatment. Conclusion Unilateral hematuria from discrete vascular lesions of the renal collecting system may be obscured by other benign co-existing conditions, such as nephrocalcinosis and nephrolithiasis. Although a simultaneous presentation is rare, flexible ureteroscopy with laser fulguration offers an ideal diagnostic and therapeutic modality for these concurrent conditions if symptoms arise.

Primary Hyperaldosteronism and Renal Medullary Nephrocalcinosis: A Controversial Association

Primary hyperaldosteronism (PA) is a common disease with a prevalence of 5–10% in unselected patients with hypertension. Medullary nephrocalcinosis is a radiological diagnosis and refers to diffuse calcification in the renal parenchyma. The three commonest causes of nephrocalcinosis are hyperparathyroidism, distal renal tubular acidosis, and medullary sponge kidney. PA is not a recognized cause of nephrocalcinosis. There are a few case reports linking PA with nephrocalcinosis published till date. In this case series, we report three cases where PA was possibly associated with medullary nephrocalcinosis. In all three cases, the common causes of nephrocalcinosis were excluded by careful clinical history, biochemical evaluation, and radiological findings. We conclude and emphasize that a diagnosis of PA as an etiology of medullary nephrocalcinosis should be sought after common causes have been excluded, at least in those with hypertension that is difficult to control.

A Novel Variant in the CASR Gene c.368T>Cp.(Leu123Ser) in a Case of Hypocalcemia Refractory to Standard Medical Therapy

Introduction: Hypoparathyroidism is characterized by low or inappropriately normal PTH production, hypocalcemia and hyperphosphatemia. Autosomal dominant hypocalcemia (ADH) type 1 is one of the genetic etiologies of this, caused by heterozygous activating mutations in the CASR gene. Some individuals fail to meet treatment goals despite standard therapy. Clinical Case: A 13-year-old male patient was admitted in the emergency department due to syncope during physical activity. There was no reference to seizures or other complaints. Standard screening for metabolic diseases revealed no changes at the 7th day of life and family history was unremarkable. There was a history of febrile seizures up to 5 years of age with several hospitalizations for diagnosis investigation that were inconclusive. Physical examination showed a positive Chvostek signal, without other changes. A basic workup revealed hypocalcemia 1.67mmol/L (NR: 2.19-2.66), hyperphosphatemia 3.06mmol/L (NR: 0.95-1.75), hypomagnesemia 0.62mmol/L (NR: 0.7-1.0), low 25Hydroxyvitamin D 8.7ng/mL (NR: >30ng/mL) and inappropriately low PTH 4.0pg/mL (NR: 16.0-87.0). Cranial computed tomography scan showed bilateral calcifications of the basal ganglia. Dual-energy x-ray absorptiometry revealed bone mineral density z-scores increased 15% in spine lumbar and decreased 7% in left femur. Cardiac ultrasound and electrocardiography were normal. The patient started therapy with intravenous calcium gluconate. During this treatment, he developed significant calcification of the peripheral veins at the site of administration, leading to intravenous therapy suspension. The dose of oral calcium, calcitriol and magnesium was gradually increased and sevelamer started to control hyperphosphatemia. Despite the optimization, the patient maintained hypocalcemia refractory to standard therapy. As a last resource strategy in therapeutic optimization, the patient started on rhPTH (1-34). Ever since, the patient has been clinically asymptomatic with biochemical stability and with a reasonable quality of life. At age 18, renal ultrasound revealed diffuse medullary nephrocalcinosis. The genetic testing revealed a novel variant c.368T>C p.(Leu123Ser) likely pathogenic in heterozygosity in the CASR gene, suggesting the diagnosis of ADH type 1. The patient′s mother did not give her consent for genetic study and patient’s father had already died with a diagnosis of acute leukemia. Conclusion: This case can be explained by the presence of a likely pathogenic variant in heterozygosity in the CASR gene that has been described in the medical literature that has not been identified in gnomAD population database, suggesting the diagnosis of ADH type 1. rhPTH (1-34) may be a treatment option for those individuals who are not well controlled on standard therapy, but long-term follow-up studies are needed to reinforce its safety.

A Rare Case of Perinatal Hypophosphatasia Treated With Asfotase Alfa

Background: Perinatal Hypophosphatasia (HPP) is a rare and lethal disorder associated with a 50–100% mortality rate, usually due to respiratory complications. HPP occurs due to a loss-of-function mutation in the ALPL gene, responsible for the function of tissue-nonspecific alkaline phosphatase (TNSALP). Clinically, HPP presents as a severe lack of bone mineralization leading to a rickets-like presentation. Clinical Case: A 4-month-old female presented from an outside hospital for the ongoing care of perinatal HPP. Prenatal scans with long-bone fractures raised concern for Osteogenesis imperfecta. However, alkaline phosphatase (ALP) at birth was <11 U/L, and vitamin B6 was elevated >250 ng/mL. Calcium, 25-OH vitamin D, and urine phosphoethanolamine were normal. A genetics panel for HPP confirmed two pathogenic autosomal recessive mutations on the ALPL gene. Treatment with asfotase alfa 3 mg/kg three times weekly was started on day two of life. The clinical course has been complicated by the need for mechanical ventilator support, seizure-event shortly after birth, recent EEG demonstrating epileptogenic potential in the bitemporal cortical regions now on treatment with Keppra, possible craniosynostosis with mild-to-moderate ventriculomegaly, and minimal grade 1 medullary nephrocalcinosis. Bone mineralization is monitored via skeletal surveys, and changes are measured using the Radiographic Global Impression of Change (RGI-C) and the Rickets Scoring Scale (RSS). After four months of asfotase alfa treatment, substantial progress in bone mineralization per RGI-C scoring has been noted, but RSS scoring still indicates severely low bone mineralization. ALP remains >3,000 U/L. Calcium, 25-OH vitamin D, and vitamin B6 are normal. Careful monitoring with weekly biochemical and urine profiles and monthly skeletal surveys, neuro assessments, and renal ultrasounds are ongoing. Conclusions: This clinical case demonstrates the improvement in bone mineralization with asfotase alfa, but the clinical course is slow and arduous. Despite the early initiation of asfotase alfa the patient’s bone mineralization remains severely low and is not in a safe range to proceed with G-tube, broviac, or tracheostomy placement. The current management goal is to maximize bone mineralization in preparation for the life-sustaining procedures mentioned above. With only a handful of surviving cases in the world, current long-term survival and outcomes for patients with perinatal HPP are unclear.

Novel Heterozygous Calcium Sensing Receptor (CASR) Genetic Variant in Child with Unique Phenotype: Hypocalcemia, Mandibular Hypoplasia, Renal Cysts and Type E Brachydactyly

Background: There are over 230 disease-causing variants in the calcium-sensing receptor gene (CaSR). Gain-of-function missense mutations in CaSR cause Autosomal Dominant Hypocalcemia (ADH) characterized by hypocalcemia (hCa), hypoparathyroidism (hPTH), and hypercalciuria. Patients with ADH are sensitive to fluctuations in serum calcium (Ca); and supplementation with Ca and vitamin D can cause inappropriate renal calcium retention leading to hypercalcemic events and long-term renal complications. Clinical Case: A 15-year-old adopted (at age 18 months) Korean female was initially diagnosed with hPTH and chronic hCa after presenting with hCa seizures. Laboratory values showed hCa (7.7 mg/dL), hyperphosphatemia (7.6 mg/dL) and hPTH (< 3 pg/mL.) Initially, she was treated with Ca supplementation (20 mg/kg/day elemental Ca), and calcitriol (0.01 mcg/kg/day). She presented at age 4 with hematuria and was found to have obstructive nephrolithiasis requiring operative intervention. Renal ultrasound (US) showed bilateral medullary nephrocalcinosis. She continued treatment with Ca and calcitriol. At age 6, a thiazide diuretic and potassium citrate supplement were added due to hypercalciuria. She had recurrent nephrolithiasis and persistent nephrocalcinosis. Follow-up renal US also showed bilateral renal cysts. Biweekly laboratory evaluation demonstrated an exuberant response to calcium supplementation. Serum Ca levels oscillated between 7.0 -10 mg/dL, but she showed minimal symptoms of hCa. At age 14, she was also recognized to have submandibular hypoplasia and brachydactyly of the 4th and 5th metacarpals and metatarsals bilaterally and genetic testing for CaSR gene mutation was requested. Sshe developed acute kidney injury and hypercalcemia, possibly precipitated by viral illness. However, 3 weeks before, calcitriol dose was increased to 1.25 mcg twice a day (0.07 mcg/kg/day). At admission, serum Ca was 12.7 mg/dL, iPTH 5.2 mg/dL, phosphorus 4.5 mg/dL, BUN 36 mg/dL, creatinine 1.85 mg/dL. Symptoms included headache, muscle spasm and throat spasm. She received intravenous fluids and recovered, but had an extended hospital stay. Targeted genetic analysis of the CaSR gene was completed, and identified a heterozygous variant (c.2506G>T, p.V836L) which is predicted to be likely pathogenic and cause ADH. After CaSR gene mutation identification, the calcitriol and also elemental Ca dosing were decreased to achieve a low Ca level (~7 mg/dL) with normal urine Ca/creatinine ratio. Patient remains asymptomatic. Conclusion: This is the first case of a novel mutation in the CaSR (c.2506G>T, p.V836L) associated with ADH, brachydactyly, renal cysts, and mandibular hypoplasia. Timely genetic testing for ADH in patients with newly diagnosed hPTH can lead to changes in therapy and improved prognosis.

Juvenile dermatomyositis: a case of delayed recognition with unusual complication of nephrocalcinosis

Juvenile dermatomyositis (JDM) is the most common inflammatory myopathy in children and is characterised by the presence of proximal muscle weakness, heliotrope dermatitis, Gottron’s papules and occasionally auto antibodies. The disease primarily affects skin and muscles, but can also affect other organs. Renal manifestations though common in autoimmune conditions like lupus are rare in JDM. We describe a child whose presenting complaint was extensive calcinosis cutis. Subtle features of proximal muscle weakness were detected on examination. MRI of thighs and a muscle biopsy confirmed myositis. Nephrocalcinosis was found during routine ultrasound screening. We report the first case of a child presenting with rare association of dermatomyositis, calcinosis cutis and bilateral medullary nephrocalcinosis.

Phenotype and Genotype Profile of Children with Primary Distal Renal Tubular Acidosis: A 10-Year Experience from a North Indian Teaching Institute

Primary distal renal tubular acidosis (dRTA) or Type 1 RTA in children is caused by a genetic defect (involved genes ATP6V0A4, ATP6V1B1, SLC4A1, FOXI1, or WDR72), which causes tubular transport defects characterized by an inability to appropriately acidify urine with resultant persistent hyperchloremic metabolic acidosis. Retrospective analysis of 28 children (14 males) under the age of 14 years with dRTA seen from 2010 to 2019 was reviewed, and detailed clinic records were analyzed. The clinical features, investigations, and response to treatment were recorded. The median age of the children at presentation was 30 months (range: 9.25–72 months), and the median age at onset of symptoms was 2 months. All the children had growth failure, polyuria, and polydipsia at presentation. Mean serum potassium, pH, bicarbonate, and anion gap at presentation was 2.3 ± 0.5 mmol/L, 7.22 ± 0.09, 13.28 ± 4.37 mmol/L, and 9.3 ± 2.18, respectively. Mean serum potassium, pH, bicarbonate at follow-up was 3.88 ± 0.6 mmol/L, 7.35 ± 0.06, and 20.13 ± 4.17 mmol/L, respectively. The median z-score for the weight for age and height for age at initial presentation was −4.77 (–7.68 to –3.74) and –4.21 (–5.42 to –2.37) and at follow-up was –3.35 (–5.29 to –1.55) and –3.84 (–5.36 to –1.63), respectively. Twenty-two (78.6%) children had medullary nephrocalcinosis. Four children had sensorineural hearing loss. Seven children had genetic testing done, and six had pathogenic or likely pathogenic variants in ATP6V1B1 and ATP6V0A4 gene. Children with dRTA have a guarded prognosis and ATP6V1B1 and ATP6V0A4 mutations are the most common implicated genetic defect in Indian children with distal RTA.

Idiopathic infantile hypercalcemia: mutations in SLC34A1 and CYP24A1 in two siblings and fathers

ObjectivesBoth CYP24A1 and SLC34A1 gene mutations are responsible for idiopathic infantile hypercalcemia, whereas loss-of-function mutations in CYP24A1 (25-OH-vitamin D-24-hydroxylase) lead to a defect in the inactivation of active 1.25(OH)2D; mutations in SLC34A1 encoding renal sodium phosphate cotransporter NaPi-IIa lead to primary renal phosphate wasting combined with an inappropriate activation of vitamin D. The presence of mutations in both genes has not been reported in the same patient until today.Case presentationHypercalcemia was incidentally detected when a 13-month-old boy was being examined for urinary tract infection. After 21 months, hypercalcemia was detected in his six-month-old sister. High dose of vitamin D was not given to both siblings. Both of them also had hypophosphatemia and decreased tubular phosphate reabsorption. Intensive hydration, furosemide and oral phosphorus treatment were given. Bilateral medullary nephrocalcinosis was detected in both siblings and their father. Serum Ca and P levels were within normal limits at follow-up in both siblings. Siblings and their parents all carry a homozygous stop codon mutation (p.R466*) in CYP24A1. Interestingly, both siblings and the father also have a heterozygous splice-site mutation (IVS6(+1)G>A) in SLC34A1. The father has nephrocalcinosis.ConclusionsA biallelic loss-of-function mutation in the CYP24A1 gene was identified as responsible for hypercalcemia, hypercalciuria and nephrocalcinosis. In addition, a heterozygous mutation in the SLC34A1 gene, although not being the main pathogenic factor, might contribute to the severe phenotype of both patients.