ABSTRACT Primary hyperoxaluria type 1 is a rare genetic disease caused by mutations in AGXT, leading to an excessive hepatic production of oxalate, resulting in urolithiasis, nephrocalcinosis and chronic kidney disease. The authors present the case of a young female with PH1 who is the first patient treated with lumasiran in Portugal, and currently has a follow-up of 18 months.

ABSTRACT Hemolytic uremic syndrome (HUS) triggered by influenza virus (iHUS) is rare. Influenza A infections have been described to trigger atypical HUS (aHUS) in individuals with an underlying genetic complement dysregulation. To date there are only few reports of Influenza B as a trigger of aHUS, all identified cases associated with mutations in the MCP or C3 gene, occasionally combined with other mutations. aHUS patients should be screened for all known disease-associated genes and screening should not be stopped after finding a mutation, to identify other genetic susceptibility factors influencing gene phenotype, particularly in patients with MCP or CFI mutations. Complement blockade using a monoclonal anti-C5 antibody, eculizumab, has greatly improved the outcome in recent years for certain groups of HUS. The decision on whether to treat or not with eculizumab should be made based on clinical and laboratorial evolution as well as molecular studies results. Influenza A and B are preventable through vaccination and strategies should be addressed for patients with complemente gene mutations identified.

ABSTRACT Primary inherited epidermal growth factor receptor defects have recently been described in severe inflammatory skin disease and diarrhoea case reports. We describe two case reports of female preterm newborns of Roma consanguineous parents who presented both with alopecia and erythroderma/ichthyosis, in addition to nephromegaly at birth in case 1. Later, they both developed hypomagnesaemia and other severe hydroelectrolyte disturbances, recurrent life-threatening sepsis and failure to thrive. Exome sequencing identified a homozygous mutation in the epidermal growth factor receptor, rarely described. Despite optimization of medical supportive care, the prognosis was poor and both patients died before the first year of life. There are few similar cases of epidermal growth factor receptor homozygous mutation reported so far. Our manuscript describes the genetics, clinical presentation, and complex treatment of our two patients, aiming to contribute to new advances in the management of this condition.

ABSTRACT Molecular genetic testing in human traits has traditionally relied on affiliated academic facilities, been focused on specific phenotypes and supported by research funding. We report the experience of the Kidney Genetics Clinic (“consulta de Doenças Renais Hereditárias”) for the past 5 years, a period during which we have outsourced genetic testing. We evaluated the impact of molecular testing in patients’ care, but we also assessed disease‑specific imaging procedures and medicines provided. During the study period, 293 individuals were evaluated. Autosomal Dominant Polycystic Kidney Disease was the most frequent diagnosis (61.8%). In 125 patients, a genetic test was available, and for 76 of these (60.8%) a pathogenic/likely pathogenic variant was identified. Depending on the phenotype, the mutation detection rate ranged from 100% (Tuberous Sclerosis Complex) to 15.4% (Autosomal Dominant Tubulointerstitial Kidney Disease). The impact of genetic testing on patients’ diagnosis and treatments is discussed. Total kidney volume was calculated in 6 patients with Autosomal Dominant Polycystic Kidney Disease and the combined volume for selected angiomyolipoma monitored in 3 individuals with the Tuberous Sclerosis Complex. Currently, 4 patients are being treated with Everolimus/Votubia™, 3 with Eculizumab/Soliris™ and 2 with Tolvaptan/Jinarc™. Our results demonstrate the feasibility of genetic molecular testing in a clinical setting while relying on outsourced sites for gene testing. We emphasize that it was only because the Kidney Genetics Clinic was given the opportunity to look after several patients affected by the same specific orphan or rare diseases (cohort enrichment) that we were able to improve diagnostic skills and deliver personalized medicines.

Resumo O raquitismo fosfopênico pode ser causado por mutações no gene PHEX (ligado ao X do homólogo da endopeptidase que regula o fosfato). Atualmente, mais de 500 mutações no gene PHEX causam raquitismo hipofosfatêmico. Os autores relatam um caso clínico de uma menina de 4 anos com histórico familiar sem relevância, que apresentou falha no crescimento e arqueamento das pernas. Os exames laboratoriais mostraram hipofosfatemia, fosfatase alcalina elevada, cálcio normal, PTH levemente elevado e níveis normais de 25(OH)D e 1,25(OH)D. O estudo radiológico mostrou deformidades ósseas no rádio e no fêmur. O diagnóstico clínico do raquitismo fosfopênico foi realizado e o estudo genético detectou uma provável variante patogênica heterozigótica do gene PHEX: c.767_768del (p.Thr256Serfs*7). Esta variante não foi descrita anteriormente na literatura ou nas bases de dados. O conhecimento sobre novas mutações pode melhorar o desfecho de pacientes. A análise genética pode ajudar a estabelecer uma correlação genótipo-fenótipo.

Abstract Phosphopenic rickets may be caused by mutations in the PHEX gene (phosphate regulating endopeptidase homolog X-linked). Presently, more than 500 mutations in the PHEX gene have been found to cause hypophosphatemic rickets. The authors report a clinical case of a 4-year-old girl with unremarkable family history, who presented with failure to thrive and bowing of the legs. Laboratory tests showed hypophosphatemia, elevated alkaline phosphatase, normal calcium, mildly elevated PTH and normal levels of 25(OH)D and 1.25(OH)D. The radiological study showed bone deformities of the radius and femur. Clinical diagnosis of phosphopenic rickets was made and the genetic study detected a heterozygous likely pathogenic variant of the PHEX gene: c.767_768del (p.Thr256Serfs*7). This variant was not previously described in the literature or databases. Knowledge about new mutations can improve patient’s outcome. Genetic analysis can help to establish a genotype-phenotype correlation.

Background: Primary hyperoxaluria type 1 is a rare autosomal recessive inherited disease, caused by mutations in AGXT gene, with an estimated incidence of 1:100.000 live births per year in Europe. Over 50% present with end stage renal disease at diagnosis. Case reports: The first case is a 14-year-old boy, second child to consanguineous parents, with history of recurrent lithiasis and ureteral dilatation starting 5 years before. Urine/stone analysis revealed calcium oxalate monohydrate crystals and markedly elevated urine oxalate excretion. Genetic tests confirmed a mutation in AGXT gene, c.1151T>C, in homozygosity. Two years after, nephrocalcinosis was identified and glomerular filtration rate gradually declined. Oxalate deposition in solid organs was excluded and successful orthotopic liver transplantation was performed, with stabilization of glomerular filtration rate. The second case is a 16-year-old girl, with recurrent episodes of renal colic. At diagnosis, she had obstructive hydronephrosis, multiple kidney stones and an estimated glomerular filtration of 42.1mL/min/1.73m2. Metabolic study showed hypocitraturia and hyperoxaluria. With dietetic measures and irregular treatment, urine oxalate excretion remained high but renal function improved. Genetic tests confirmed the presence of two pathologic variants in AGXT gene: c.731T>C and c.1151T>C in compound heterozygous. Conclusions: Recurrent urolithiasis and nephrocalcinosis in children along with family history/consanguinity should raise the suspicion of Primary Hyperoxaluria type 1. Conservative treatment may increase renal survival. Effects of systemic oxalosis must be screened when glomerular filtration rate declines below 30-50mL/min/1.73m2, and sequential or combined liver and kidney transplantation should be considered.

Nephronophthisis is an autosomal recessive cystic kidney disease characterized by reduced concentrating ability of the kidney, chronic tubulointerstitial nephritis, cystic renal disease and progression to end-stage renal disease. In 10-20% of cases it is associated with a variety of other ciliopathy phenotypes. A 10-year-old caucasian female patient presented to our hospital with a history of uncontrolled vomiting and signs of moderate dehydration. Past medical history was significant for reduced visual acuity and moderate intellectual disability with a minor cerebellar dysplasia. She also complained of polyuria, polydipsia and enuresis for several years. Laboratory screening revealed a low urine specific gravity and renal insufficiency that were maintained after intravenous rehydration. Based on the clinical picture, a ciliopathy was considered, particularly nephronophthisis with neurological manifestation and confirmed by genetic molecular analysis. In conclusion, this case report reinforces the diagnostic challenge of nephronophthisis because of its unspecific presentation and significant overlap with other ciliopathy phenotypes. Therefore, in the presence of a urinary concentration defect and renal impairment, with or without other extra-renal manifestations, nephronophthisis should be considered in the differential diagnosis to allow a prompt diagnosis and therapeutic intervention.

Ifosfamide is an antineoplastic drug widely used in the treatment of paediatric malignancies. However, in up to 50% of patients, it is associated with nephrotoxicity ranging from asymptomatic tubulopathy to overt renal failure. A two-year-old Caucasian boy was diagnosed with stage IV Burkitt lymphoma, with hepatic and renal and bone marrow involvement. Baseline evaluation showed GFR of 60 mL/min/1.73 m2. He started chemotherapy with LMB 96 protocol group B with 5 courses of chemotherapy with vincristine, cyclophosphamide, doxorubicin, prednisone, and intrathecal administration of cytarabine and methotrexate. After the first chemo protocol, the patient was in remission and recovered normal renal function, but three months later he relapsed with involvement of the liver and kidneys. The patient initiated a salvage regimen with R-ICE (rituximab - ifosfamide, carboplatin, etoposide) intrathecal methotrexate and cytarabine and allogeneic stem cell transplantation was proposed. After achieving complete remission, he underwent allogeneic stem cell transplantation with busulfan and cyclophosphamide. Graft versus host disease prophylaxis was made with tacrolimus and methotrexate and infection prophylaxis with fluconazole and acyclovir. However, during treatment of the relapse, the patient presented downward crossing of weight and height centiles without recovery after treatment terminus and, following transplantation, consecutive laboratory testing suggested tubulopathy. Upon nephrologist referral, he was diagnosed with Fanconi syndrome and adequate supplementation was initiated with improvement of the patient’s general condition and slow centile catch up. After literature review, the most probable causing agent was determined to be ifosfamide, as the nephrotoxic effects of the other medications prescribed tend to be reversible after stopping. Nephrotoxicity secondary to chemotherapy is a major cause of morbidity in paediatric cancer survivors. Our case represents a rare situation with unspecific clinical signs. Clinicians must be alert to the necessity of close monitoring to identify renal toxicity, mainly tubular dysfunction, as early as possible and allow adequate supplementation, which is crucial in preventing side effects.

Introduction and Aims: Nephrocalcinosis is characterized by the deposition of calcium in the kidney parenchyma and tubules. The renal prognosis depends on the underlying cause, emphasizing the importance of its identification. We aim to review the data of children with nephrocalcinosis concerning etiology, clinical manifestations, growth and renal function at presentation and outcomes. Methods: Retrospective study of the records of children (<18 years) with nephrocalcinosis followed by a pediatric nephrology unit of level III hospital, between 2008-17. Clinical features, etiology, treatment and outcomes were evaluated. Results: We identified 35 cases: 24 isolated (69%) and 11 with nephrolithiasis (31%). The group was mostly constituted of girls (54%). Median age at presentation was 6 years (7 months - 17 years old); 40% of patients were under 2 years of age, 31% between 3 and 9 years and 29% older than 10 years. Mean follow-up was 4 years (1-9). The most common clinical manifestation was failure to thrive in the first year of life (34%) and flank or abdominal pain (20%); in 23% it was an incidental finding. Eleven percent of patients had a systemic syndromic disease. Renal function at diagnosis was normal in all children. The most frequent causes were metabolic abnormalities (23%), hereditary tubulopathies (23%), prematurity (20%) and pharmacologic (14%). Eleven percent were considered idiopathic. In a logistic regression analysis, sex, age of presentation and familiar history of nephrocalcinosis showed no correlation with nephrocalcinosis, nephrocalcinosis and nephrolithiasis or hereditary/metabolic etiologies. Discussion: Despite the small sample, in this study, the hereditary and/or metabolic disorders were the main cause of nephrocalcinosis. Associated symptoms and comorbidities, such as prematurity, growth retardation, intestinal malabsorption, or bone demineralization, should be evaluated for diagnostic purposes. No patient developed chronic kidney disease.

Introduction and Aims: Nephrolithiasis incidence in children has increased considerably. It is associated with substantial morbidity, recurrence and increased adulthood cardiovascular risk and chronic kidney disease. A thorough investigation is essential, as rare forms of urolithiasis have increased risk of renal failure. We aim to determine the epidemiology and outcomes of a pediatric population with nephrolithiasis presented in a nephrology unit of a tertiary centre. Methods: Retrospective study of the records of all children (<18 years) with nephrolithiasis diagnosis between 2008-17. Clinical features, etiology, recurrence, treatment, and outcomes were evaluated and compared throughout the study period through two equal periods (2008-12 versus 2013-17). Results: We identified 80 cases: isolated nephrolithiasis (86%) and associated with nephrocalcinosis (14%). Mean follow-up was 36 months (14-120). Median age at presentation was 8.6 years [3 months - 17 years]: 21% < 2 years-old and 46% ≥ 10 years. The annual ratio of referrals for nephrolithiasis increased on average 1.2% per year [0.3-11.8%]. Multiple etiological factors were present in 34%. A metabolic abnormality was identified in 54%: hypocitraturia (34%), hypercalcuria (24%), hyperoxaluria (15%), hyperuricosuria (15%) and cystinuria (1%), without age predominance (p=0.2). Urinary tract infection (24%) was the next most significant etiology and was more frequent below 2 years of age (p=0.001) and associated with struvite calculi (p=0.033). Median age at diagnosis was significantly lower in the study’s first half (5 vs 10 years; p=0.019) and an infectious etiology was more frequent (p=0.043). In a logistic-regression analysis, a family history of nephrolithiasis was associated with a metabolic cause (p<0.01). Sixty-three percent became stone free and 24% had recurrence. Discussion: Nephrolithiasis new referrals gradually increased throughout the study period. The most common etiology was metabolic, which is usually responsible for nephrolithiasis appearance and its recurrence, emphasizing the need for a complete evaluation.

Pheochromocytoma and renal artery stenosis are surgically treatable causes of hypertension. Although rare, the coexistence of pheochromocytoma and renal artery stenosis has been described in case reports. Common pathophysiological mechanisms other than extrinsic compression may be involved in this association, such as catecholamine-induced vasospasm. The early recognition of the association of pheochromocytoma with renal artery stenosis is essential for appropriate treatment planning. We present the case of a previously healthy tenyear-old boy who presented with hypertensive encephalopathy, tachycardia and diaphoresis. Hypertension was found to be secondary to a catecholamine-producing tumor associated with coexisting renal artery stenosis. Hypertension resolved a few months after successful pheochromocytoma excision, without renal artery revascularization

Introdução: A abordagem inicial do grande queimado até à sua estabilização hemodinâmica e hidroeletrolítica é fundamental para diminuir a morbimortalidade. Material e Métodos: Estudo retrospetivo, descritivo e analítico, de todos os internamentos por queimadura numa Unidade de Cuidados Intensivos Pediátricos durante o período de 20 anos (Abril/1991 a Dezembro/2010). Avaliaram-se parâmetros nosodemográficos, agente causal, gravidade e extensão da queimadura, procedimentos, terapêutica, complicações e resultados. Resultados: Ocorreram 137 internamentos por queimadura correspondentes a 123 doentes e a 1,8% do total de internamentos na UCIP. A mediana de idade foi 3,6 anos e 62,4% era do sexo masculino. Verificou-se maior incidência em Agosto (13,0%). Foram agentes da queimadura: líquido fervente (38,1%), fogo (38,1%) e eletricidade (23,9%). A mediana da superfície corporal queimada foi de 30% (0,5-92,0%), com queimaduras do terceiro grau em 59,0% dos doentes. Necessitaram de ventilação mecânica 45,5% e de cateter venoso central 64,2% dos doentes. As complicações incluíram: sépsis (29,2%), falência respiratória (21,1%), falência cardiovascular (16,5%) e falência multiorgânica (18,8%). Verificou-se melhoria em 88,6% dos casos e ocorreram 10 óbitos (8,1%), nove dos quais nos primeiros 10 anos do estudo e nove devido a causa infeciosa. No entanto, o score avaliador do risco de mortalidade (PRISM), índice de intervenção terapêutica (TISS) e o risco de probabilidade de morte (RPM) foram mais elevados no segundo decénio. Conclusões: Nos últimos anos do estudo, apesar do maior número de admissões e da sua maior gravidade, verificou-se uma diminuição do número de mortes, o que poderá dever-se à melhoria dos cuidados prestados.

Background: Initial approach of severely burned patient until hemodynamic and hydroelectrolytic stabilization is crucial to minimize morbidity and mortality. Material and methods: Retrospective descriptive and analytic study of all burned patients admitted in a Paediatric Intensive Care Unit during a 20 year period (between April/1991 and December/2010). Nosodemographic data, causal agent, severity and extension of burn, procedures, treatment, complications and outcome were analyzed. Results: There were 137 admissions for burn, corresponding to 123 patients and to 1.8% of all admissions in the PICU. The median age was 3.6 years, and 62.4% were male. Higher incidence of cases was found in August (13.0%). Burning agents were: boiling liquid (38.1%), fire (38.1%) and electricity (23.9%). The median total body surface burned area was 30% (0.5- 92.0%), 59.0% corresponding to third degree burns. Mechanical ventilation was needed in 45.5% and central venous catheter in 64.2% of patients. Complications included: sepsis (29.2%), respiratory failure (21.1%), cardiovascular failure (16.5%) and multiorgan failure (18.8%). Patients recovered in 88.6% of cases and there were 10 deaths (8.1%), nine of them in the first 10 years of the study, and nine due to infection. However, the paediatric risk of mortality score (PRISM, the therapeutic intervention scoring system (TISS) and the risk probability of death (RPM) were higher in the second decade. Conclusion: In the last years of the study, despite the higher number of admissions and greater severity, there was a decrease in the number of deaths, which may be related to the improvement of care in these patients.