Renal Tubular Disorder Research Articles

A novel heterozygous likely pathogenic SLC5A2 variant in a diabetic patient with glucosuria and aminoaciduria.

Familial renal glucosuria (FRG) is a rare renal tubular disorder characterized by increased urinary glucose excretion despite normoglycemia. It is most commonly caused by pathogenic variants in the solute carrier family V member 2 (SLC5A2) gene. This gene encodes the sodium-glucose cotransporter 2, crucial for glucose reabsorption. We report the case of a 44-year-old male referred to the endocrinology outpatient clinic for unexplained glucosuria despite well-controlled diabetes mellitus with metformin and gliclazide therapy. His main complaints were nocturia and an unintentional 5 kg weight loss in 1 year. A 24-h urinary collection revealed overt glucosuria (23.3 g/1.73 m2/24 h), generalized aminoaciduria, and increased uric acid excretion (fractional excretion: 6.4%). Whole-exome sequencing revealed a novel heterozygous c.469-1G>A likely pathogenic variant in the SLC5A2 gene. Specific analysis of the maturity-onset diabetes of the young type (MODY) gene panel showed no pathogenic variants in the hepatocyte nuclear factor-1A (HNF-1A; MODY3) nor in other MODY-associated genes. We assume that the association of glucosuria, aminoaciduria, and increased uric acid excretion can be explained by the combination of diabetes and the likely pathogenic SLC5A2 variant in this patient. In conclusion, we describe a well-controlled diabetic patient with FRG, associated with a novel heterozygous c.469-1G>A likely pathogenic variant in the SLC5A2 gene. The diagnosis of a renal tubular disorder should be considered in patients with unexplained glucosuria and diabetes mellitus, especially if the latter is well controlled. FRG usually presents with glucosuria but may be associated with generalized aminoaciduria and hyperuricosuria. Genetic analysis should be considered in patients with young-onset diabetes and glucosuria, particularly with a positive family history.

389-P: ChREBP-ß Aggravates Fructose-Induced Renal Tubular Reabsorption Disorder by Regulating Endoplasmic Reticulum Stress and Mitochondrial Dysfunction

389-P: ChREBP-ß Aggravates Fructose-Induced Renal Tubular Reabsorption Disorder by Regulating Endoplasmic Reticulum Stress and Mitochondrial Dysfunction

Demystifying Renal Tubular Disorders in children : A simplified approach

Renal tubular disorders essentially include all disorders of the highly specialized channels of the renal tubular system, from the proximal convoluted tubule to the cortical and medullary collecting ducts. This tubular system is responsible for reabsorption of 99% of glomerular ultrafiltrate, which contains a large amount of fluid (approximately 180 L/day) as well as most electrolytes and many metabolites such as glucose (G), amino acids, bicarbonate (HCO3-), phosphate (PO4 3-), and low-molecular-weight proteins and is essential for maintaining fluid, electrolyte, and acid–base balance. In this review, we will briefly discuss when to suspect a renal tubular disorder, a simplified algorithm for evaluation, and specific mutations of a few common disorders.

Research progress on the pharmacological activity and mechanism of chlorogenic acid in alleviating acute kidney injury in sepsis patients

Sepsis-induced acute kidney injury (SAKI) is a serious perioperative complication and a common clinical syndrome characterized by a rapid deterioration in renal function with a high incidence of 70%. The causes of SAKI include impaired mitochondrial function of renal tubular epithelial cells, oxidative stress, inflammatory reaction and renal microcirculation disorder. Chlorogenic acid, as a natural product of plant origin, has various biological activities, such as antibacterial, antiviral, and anti-tumor, and plays a significant role in the treatment of SAKI. This article reviews the pharmacological activities of chlorogenic acid and the signaling pathways involved in relieving SAKI, in order to provide a theoretical basis for in-depth study of the mechanisms underlying the alleviation of SAKI and the confirmation of potential therapeutic targets.

A case of Gitelman syndrome with homozygous SLC12A3 deletion presenting with epilepsy

BackgroundGitelman syndrome (GS) is a rare autosomal recessive hereditary renal tubular disorder characterized by hypokalemia, metabolic alkalosis, hypomagnesemia, and hypocalciuria.Case presentationWe report a rare case of GS with homozygous loss of SLC12A3 presenting with epilepsy. The patient was a 21-year-old female who sought medical attention for seizures. Her condition primarily manifested as epilepsy, diarrhea, and weakness of limbs. Through genetic analysis, we confirmed the diagnosis of this case and formulated a comprehensive approach for its management.ConclusionsThis case report extends the clinical symptoms of GS and provides a complete family of GS as a reference for subsequent studies.

Coexistence of Neonatal Bartter Syndrome and Congenital Cutis Laxa, in which a new mutation in SLC12A1 was identified

Introduction: Neonatal Bartter Syndrome (NBS) is an extremely rare congenital chronic renal tubular transport disorder characterized by preterm birth, polyhydramnios, polyuria, salt wasting, and severe dehydration. Congenital Cutis Laxa (CCL) is a rare disease characterized by loss of skin flexibility and laxity, and atypical facial appearance.
 Case Presentation: A 1290-gram female baby at 30+6 weeks of gestation was hospitalized due to premature birth and respiratory distress. During physical examination, an atypical facial appearance, wrinkles on the forehead, skin laxity, and philtrum were visible as well as a small chin and arachnodactyly in the fingers and toes. The patient displayed metabolic alkalosis in her blood gases. The patient, with an atypical face and current findings submitted her exome for genetic diagnosis. Genetic analysis revealed the presence of homozygous NM_001184832.2:c.2485+5G>A (rs749269268) in SLC12A1, and NBS Type 1 was diagnosed. A novel heterozygous NM_000501.4:c.352G>T, p.Val118Phe (rs781922544) variant was detected in ELN, and CCL syndrome with autosomal dominant inheritance was diagnosed.
 Conclusions: The rare co-occurrence of NBS and CCL syndrome in our patient was seen as a mere coincidence. Since this is the first reported case in the literature, it was deemed appropriate to present this case.

BARTTER SYNDROME TYPE I. CLINICAL CASE OF A PREGNANT WOMAN WITH POLYHYDRAMNIOS

Bartter syndrome is an inherited renal tubular disorder characterized by salt wasting, hypokalemia and metabolic acidosis due to impaired salt reabsorption in the ascending limb of the loop of Henle in the renal nephrons. Currently, five types of the disease are known. While the clinical signs of type 3 (classical type) appear in childhood and later ages, types 1, 2, 4, 5 (antenatal type) are characterized by severe polyhydramnios in the antenatal period and antenatal fetal death. This article is about a pregnant woman carrying a fetus with antenatal Bartter syndrome type I.

#3572 CLINICAL AND GENETIC CHARACTERISTICS OF CHILDREN WITH BARTTER SYNDROME: A SINGLE CENTER LONG-TERM EXPERIENCE

Abstract Background and Aims Bartter syndrome is an autosomal recessive renal tubular disorder. Clinical diagnosis can be challenging due to rarity and phenotypic overlap. Little information is available on a long term follow-up in Bartter syndrome. Our aim was to describe clinical -genetic correlations as well as our experience from the long term follow up of these patients. Method Clinical and genetic characteristics of patients with Bartter syndrome at diagnosis and long term follow up are reported in 19 children. Genetic testing (whole exome sequencing, WES) was done in 14/19 patients. The study period was 17 years (January 1, 2006 to December 31, 2022). Results 16 Caucasian and 3 of gipsy origin (13 boys, 68%) were included. The median age at diagnosis was 0,52 yrs. Median follow up time was 9.8yrs (IQR 6.86-13.8). WES revealed 6 mutations in KCNJ1 genes, 5 in SLC12A1 and 3 in CLCNKB genes. 4 new mutations were identified (3 in KCNJ1 genes and 1 in SLC12A1. 18/19 children were born pre-term (including 2/3 patients with CLCNKB). Nephrocalcinosis was present in 18/19 patients (included the 3 patients with CLCKNB mutations). 4/6 patients with KCNJ1 mutations presented initially with hyperkalemia. Medical treatment in the last follow up included supplementation with potassium in 18, non -steroidal anti-inflammatory agents in 15 and gastroprotective drugs in 13, ramipril in 2. 2/19 received recombinant growth hormone. At last follow up body weight and height were within normal ranges in 16/19 (84%) patients. Hyperparathyroidism (median time of PTH 151.5 pg/ml) have 6/11 (56%) of patients with Bartter I (ΚCNJ1mutation) and Bartter II (SLC12A1 mutation) and only 1/3 with Bartter III (CLCNKB mutation). 2/19 patients have proteinuria. Chronic kidney disease (CKD) occurred in 7/19 (37%) suggesting that the long term prognosis can be unfavorable (4 CKD stage II, 3 CKD stage III). Of note 2 patients with CKD had impaired renal function since diagnosis while the remaining 5 progressed gradually during followup. Conclusion WES is useful in dealing with the phenotypic heterogeneity of Bartter syndrome. Our results emphasize the need for early diagnosis, regular followup and appropriate treatment in order to maintain normal renal function and achieve normal final height and weight.

Gitelman Syndrome – A Case Report

Hypokalaemia is an electrolyte disorder, commonly encountered in clinical practice. Sometimes, it may present with severe life-threatening complications. We present here a case of 22-year-old female, who was admitted to intensive care unit, for severe hypokalaemia associated with cardiac and neurological complications. She had recurrence of such episodes. On detailed clinical and biochemical evaluation, she was diagnosed to have Gitelman syndrome (GS). She was treated with intravenous potassium and magnesium supplementation under cardiac monitoring and other supportive management. She was discharged in stable condition, on oral supplements, and remained stable on follow-up visits. GS is an autosomal recessive and renal tubular disorder characterised by hypokalaemic metabolic alkalosis with hypomagnesaemia, hypocalciuria, secondary hyperreninemic aldosteronism and hypotension. The disease is caused by biallelic inactivating mutations within the SLC12A3 gene encoding the thiazide-sensitive sodium chloride cotransporter expressed within the apical membrane of cells, lining the distal convoluted tubule. Since GS is an autosomal recessive trait, the recurrence risk for people with an affected child is 25%. It is very important to completely evaluate a patient with hypokalaemia to find the underlying cause. There can be various etiological factors for hypokalaemia ranging from common to rare disorders. If underlying aetiology remains undiagnosed, there may be recurrence as well as increased morbidity and mortality. GS is one such disorder, which needs prompt diagnostic evaluation and treatment.

Dent disease manifesting as nephrotic syndrome.

Dent disease is an X-linked recessive renal tubular disorder, which is mainly caused by mutations of the CLCN5 gene and OCRL gene. It is characterized by low molecular weight proteinuria, hypercalciuria, nephrocalcinosis or nephrolithiasis, and progressive renal failure. Nephrotic syndrome is a glomerular disorder characterized by massive proteinuria, hypoalbuminemia, edema, and hyperlipidemia. In this study, we report two cases of Dent disease manifesting as nephrotic syndrome. Two patients were initially diagnosed with nephrotic syndrome due to edema, nephrotic range proteinuria, hypoalbuminemia, and hyperlipidemia, and responded to prednisone and tacrolimus therapy. Genetic testing revealed mutations in the OCRL and CLCN5 genes. They were eventually diagnosed with Dent disease. Nephrotic syndrome is a rare and insidious phenotype of Dent disease, and its pathogenesis is not fully understood. Patients with nephrotic syndrome are recommended to routinely undergo urinary protein classification and urinary calcium testing, especially those with frequently recurrent nephrotic syndrome and poor response to steroid and immunosuppressive therapy. To date, there is no effective drug treatment for Dent disease. About 30% to 80% of patients progress to end-stage renal disease at the age of 30-50.

Clinicopathological Features of Gitelman Syndrome with Proteinuria and Renal Dysfunction

Introduction: Gitelman syndrome (GS) is a rare renal tubular salt-wasting disorder. Besides kidney electrolyte loss, proteinuria and renal dysfunction were also observed. However, their incidence, risk factors, pathological features, and prognosis were unclear. Methods: We retrospectively reviewed 116 GS patients and analyzed their clinical, genetic, and pathological characteristics. We also systematically reviewed articles on GS with proteinuria and renal dysfunction. Results: Twenty-three GS patients had proteinuria (69.6%) and renal dysfunction (43.5%) with a mean age of 35.3 ± 13.2 years, and 65.2% were male. Compared to patients without proteinuria or renal dysfunction, these patients had elevated plasma angiotensin II level (440.2 ± 351.7 vs. 253.2 ± 187.4 pg/mL, p = 0.031) and three times higher incidence of diabetes. The renal pathology of nine biopsied patients indicated hypertrophy of the juxtaglomerular apparatus (100%), chronic tubulointerstitial changes (66.7%), intrarenal vascular changes (66.7%), and glomerulopathy (55.6%). More extensive renin staining was observed in patients with GS than in the control group with glomerular minor lesion (p < 0.001). During a median of 85 months (range, 11–205 months) of follow-up for 19 out of the 23 GS-renal patients, the renal function was generally stable, except one died of cancer and one developed end-stage renal disease because of concomitant membranous nephropathy and IgA nephropathy. Conclusion: Proteinuria and renal dysfunction were more common than expected and might indicate glomerulopathy and vascular lesions besides a tubulointerstitial injury in GS. Renal function may maintain stable with effective therapy in most cases.

An Unusual Case of BSND Gene–Related (Type IV) Bartter Syndrome Presenting as Antenatal Bartter Syndrome: A Case Report and Review of Literature

Abstract Bartter syndrome is a group of autosomal recessive renal tubular disorders; it has two types of presentation: antenatal and classic. The antenatal type presents as severe unexplained polyhydramnios in the second trimester. This is due to fetal urinary losses of sodium, chloride, and potassium, leading to fetal polyuria. The classic type presents in the late neonatal or infancy stage, with dehydration, dyselectrolytemia, failure to thrive, and nephrocalcinosis. Antenatal scans are normal in such cases. Type I and II Bartter syndrome presents in the antenatal period, whereas type IV has a classic presentation. We describe an unusual case of type IVa Bartter syndrome presenting in the antenatal period, with severe polyhydramnios. The initial diagnosis was made based on amniotic fluid chloride levels and later confirmed by performing a genetic test. Genetic testing is important for confirming diagnosis and prognostication regarding the condition.

A Study on the CLCN5 Gene in Iranian Patients: A Report of Novel and Recurrent Mutations

Introduction: Dent’s disease is an X-linked inherited renal tubular disorder characterized by proteinuria, hypercalciuria, nephrocalcinosis, nephrolithiasis, rickets, and end-stage renal disease. Almost 60% of patients have causative mutations in the CLCN5 gene (Dent 1), and 15% of affected individuals have mutations in the OCRL1 gene (Dent 2). The aims of this study are to identify CLCN5 mutations in Iranian families with Dent’s disease and to characterize the associated clinical syndromes. Methods: We studied 14 patients from 13 unrelated Iranian families with a clinical diagnosis of Dent’s disease. Proteinuria was detected in all patients. Nephrolithiasis was found in 5 patient, and hematuria in 2 patients. Most of the affected individuals had nephrocalcinosis. PCR-sequencing for the CLCN5 gene was performed in all 14 patients. Next-generation sequencing (NGS) has also been performed in one patient who we did not find causative mutation. Results: We identified four different CLCN5 mutations including one missense mutation (c.731C>T), one nonsense mutation (c.100C>T), and two novel mutations, consisting of one frameshift mutation (c.1241_1242dupAA) and one splicing mutation (c.805-2A>G). We also identified one OCRL1 mutation, one splicing mutation (c.1466 + 1G>A), using NGS. Conclusion: This is the first report to characterize mutations in the CLCN5 gene in Iranian patients with Dent’s disease and expands the spectrum of CLCN5 mutations by reporting two novel mutations, c.1241_1242dupAA and c.805-2A>G.

Pattern of hereditary renal tubular disorders in Egyptian children.

Hereditary renal tubular disorders (HRTD) represent a group of genetic diseases characterized by disturbances in fluid, electrolyte, and acid-base homeostasis. There is a paucity of studies on pediatric HRTD in Egypt. In this study, we aimed to study the pattern, characteristics, and growth outcome of HRTD at an Egyptian medical center. This study included children from one month to < 18-years of age with HRTD who were diagnosed and followed up at the Pediatric Nephrology Unit of Sohag University Hospital from January 2015 to December 2021. Data on patients` demographics, clinical features, growth profiles, and laboratory characteristics were collected. Fifty-eight children (57% males; 72% parental consanguinity; 60% positive family history) were diagnosed with seven HRTD types. The most commonly encountered disorders were distal renal tubular acidosis (distal renal tubular acidosis [RTA] 27 cases, 46.6%) and Bartter syndrome (16 cases 27.6%). Other identified disorders were Fanconi syndrome (6 cases with cystinosis), isolated proximal RTA (4 cases), nephrogenic diabetes insipidus (3 cases), and one case for each RTA type IV and Gitelman syndrome. The median age at diagnosis was 17 months with a variable diagnostic delay. The most common presenting features were failure to thrive (91.4%), developmental delay (79.3%), and dehydration episodes (72.4%). Most children showed marked improvement in growth parameters in response to appropriate management, except for cases with Fanconi syndrome. Last, only one case (with cystinosis) developed end-stage kidney disease. HRTD (most commonly distal RTA and Bartter syndrome) could be relatively common among Egyptian children, and the diagnosis seems challenging and often delayed.

Dent Disease Type 1: Still an Under-Recognized Renal Proximal Tubulopathy: A Case Report

Dent disease is a rare renal tubular disorder that appears almost exclusively in males. The diagnosis is still challenging, and therefore Dent disease is occasionally misdiagnosed. We report a case of a 45-year-old man with Dent disease who developed renal failure. Since the age of 7 months, he persistently exhibited proteinuria. At the age of 24 years, he underwent kidney biopsy, which revealed focal segmental glomerulosclerosis. The patient’s brother was found to have proteinuria since he was 2 years old. At the age of 45 years, the patient was transferred to a tertiary care nephrologist, and Dent disease was suspected. Genetic testing revealed a CLCN5 mutation. We highlight the broad spectrum of clinical manifestations in Dent disease and the importance of having a high clinical suspicion to attain a definitive diagnosis. Furthermore, future research regarding the clinical course of the disease, prognosis, and effective treatment options is needed.

Screening for an Underlying Tubulopathy in Children With Growth Failure, Simply Maths?

BackgroundInvolving pediatric nephrological input in the clinical diagnostic work-up of children with short stature, gave rise to the hypothesis that the presence of an underlying renal tubular disorder in children with short stature is possibly underestimated. This study focussed on the added value of calculated urinary fractional excretion (FE) in the early detection of tubular disorders in children with growth failure.MethodsThis trial was designed as an observational study analyzing the medical files of children between 5 and 16 years who had been referred for short stature to the pediatric endocrinology outpatient clinic at the University Hospital Antwerp between 25/01/2015 and 01/03/2019. Based on the laboratory results of the simultaneously taken blood and urine sample, the fractional excretions of Sodium, Chloride, Potassium, Calcium, Phosphate, and Magnesium were calculated.ResultsOf the 299 patients, 54 patients had at least one deviating fractional excretion value, requiring further investigation (control sample of blood and urine, kidney ultrasound or 24 h urine collection). Genetic screening for tubulopathies was performed in 19 patients. In 5 patients (1.7% of the total population) a tubulopathy was confirmed based on genetic analysis.ConclusionThis study explored the possibility of using fractional excretions as a screening test to obtain an earlier diagnosis of tubular disorders in children with short stature. Of the 299 patients, 5 patients were diagnosed with a genetically confirmed tubulopathy. Based on these results, we propose a flowchart for an additional work-up in all children with a deviating fractional excretion.

Study of the Involvement of Mitochondria in Dent’s Disease Using a Mice Model

Dent's disease is a rare renal tubular disorder characterized by low‐molecular‐weight‐proteinuria, hypercalciuria with nephrocalcinosis or nephrolithiasis, and progressive renal failure. It is frequently associated with inactivating mutations of the CLCN5gene coding for the 2Cl‐/H+ exchanger ClC‐5. In the kidney, ClC‐5 is mainly expressed in early endosomes of proximal tubules (PT) cells where it optimizes the function of the vacuolar H+‐ATPase to ensure proper endocytosis of low‐molecular‐weight‐proteins.To better understand the cellular mechanisms involved in Dent’s disease, we have generated a novel Knock‐In mouse model carrying the ClC‐5 N340K pathogenic mutation. We have previously demonstrated that these mice display similar clinical features to those observed in patients with Dent’s disease. Interestingly, we observed an increase of oxidative stress in their kidney, as evidenced by higher expression of the NADPH oxidase 4, increased H2O2production, and ROS‐related total protein damage in PT cells.Such cellular stress may arise from dysfunctional mitochondria in PT. Here, we therefore investigated the aspect of these organelles in PT cells of WT and N340K 3 month old mice using transmission electron microscopy. Compared to WT mice, mitochondria from mice carrying the N340K mutation exhibited morphologic alterations such as increased roundness, indicating that their function may be altered. Furthermore, to identify potential markers whose urinary excretion could be associated with the progression of Dent’s disease, using mass spectrometry, we performed metabolomic analyses of urine form WT and transgenic mice aged of 4, 7 and 10 months. We demonstrated changes in the excretion of metabolites that are crucial of mitochondrial metabolism (tryptophan, quinolinic acid, malate, oxaloadipate, linolenic acid and butyric acid), suggesting that the NAD+ synthesis pathway, the citric acid cycle, and beta oxidation are affected.The present study shed more light on the pathophysiology of Dent’s disease by suggesting that a mitochondrial dysfunction is involved in this disorder.

Preliminary Study for New Markers of Early Tubuloglomerular Injury and Renal Inflammation in Patients with Visceral Leishmaniasis Receiving Liposomal Amphotericin B Treatment.

Visceral leishmaniasis is treated with liposomal amphotericin B (L-AMB), which is associated with nephrotoxicity. Thus, we aimed to investigate nephrotoxicity through novel renal biomarkers in patients with visceral leishmaniasis during L-AMB use. Ours was a prospective study with 17 patients with visceral leishmaniasis treated with L-AMB during their hospital stay. Laboratory tests, renal parameters, urinary biomarkers (urinary kidney injury molecule 1, urinary monocyte chemoattractant protein 1 [uMCP-1], sodium-potassium-2 chloride cotransporter, sodium-hydrogen exchanger 3), and serum inflammatory biomarkers (MCP-1, interferon-γ, and IL-6) were evaluated in two periods: before and during L-AMB use. Glomerular filtration rate, creatinine, proteinuria, and albuminuria were similar before and during L-AMB use. IL-6 levels, aquaporin 2, and sodium-hydrogen exchanger 3 expression decreased, whereas uMCP-1 and urinary kidney injury molecule 1 levels increased during L-AMB treatment. In patients who developed acute kidney injury, uMCP-1 showed higher levels. L-AMB aggravated tubuloglomerular lesions, inflammation, and renal tubular disorders. Thus, patients treated with L-AMB need to be monitored for inflammatory and electrolyte disturbances to prevent acute kidney injury, longer length of hospital stay, higher public costs, and mortality.

Novel SLC12A1 mutations cause Bartter syndrome in two patients with different prognoses

BackgroundBartter syndrome is an inherited renal tubular disorder that is characterized by hypokalemic, hypochloremic metabolic alkalosis in which the primary defect is a deficiency of transporters involved in sodium chloride reabsorption. Bartter syndrome type 1 is caused by SLC12A1 mutations. MethodsThe patients were from two unrelated non-consanguineous Chinese families. Both patients presented with intrauterine growth retardation, premature delivery, failure to thrive, polyuria and metabolic alkalosis. Whole-exome sequencing was used to identify the causative gene. ResultsExome sequencing identified three novel SLC12A1 mutations in our patients. And we found the two patients had significantly different outcomes when they were two years of age. Moreover, we identified four novel variants of SLC12A1 that were likely to be pathogenic, from our in-house database. A review of the whole-exome sequencing data of patient 1 lead to her brother being genetically diagnosed with pulmonary alveolar microlithiasis, which was caused by compound heterozygous SLC34A2 variations. ConclusionWe reported two children from one family who were affected by different rare conditions. This study expanded the mutation spectra of the SLC12A1 and SLC34A2 genes. We showed the important role of early genetic testing for disease diagnosis and emphasized the importance of standardized treatment and management.

POS-084 A RARE GENETIC DISORDER PRESENTING AS RECURRENT URINARY TRACT INFECTION IN CHILDREN

Familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) is a rare autosomal recessive renal tubular disorder. The incidence is <1/1,000,000 individuals and >50% cases develop chronic kidney disease (CKD) by 2nddecade of life. It presents with non-specific symptoms like failure to thrive, abdominal pain, polydipsia, polyuria and clinical features of urinary tract infection (UTI). To the best of our knowledge, only 5 case reports have been published from the Indian sub-continent and none describing long term follow up.