Schimke immuno-osseous dysplasia. A case report in Colombia.

Background: Schimke immune-osseous dysplasia (SIOD) is an ultra-rare multisystemic, monogenic, and autosomal recessive inherited disease caused by biallelic mutations in the SMARCAL1 gene. Approximately 100 cases have been reported worldwide. The disease is characterized by skeletal, renal, and immunological abnormalities. Case description: This is a 6-year-old female patient who debuted with nephrotic syndrome at five years of age, with a switch to corticosteroid resistance and poor response to immunosuppressive treatment received. The patient was admitted and referred to our institution due to convulsive status. During her hospitalization, thrombosis was found in the left renal vein, and a renal biopsy report of Collapsing Focal and Segmental Glomerulosclerosis (FSGS) was obtained. The patient had multiple infections during hospitalization, with T lymphocyte lymphopenia and severe IgG hypogammaglobulinemia. Additionally, given dysmorphic facies, delayed weight-height development, and spondyloepiphyseal dysplasia, exome sequencing was performed, finding an homozygous pathogenic variant c.1933C > T p.Arg645Cys in SMARCAL1, compatible with the diagnosis of SIOD. Discussion: We present the case of a patient that exhibited a severe phenotype of the disease, with skeletal, renal, severe combined immunological compromise and cerebrovascular involvement during follow-up, and the available proposed mechanisms of the disease focused on the clinical manifestations of this patient. It is the first case of SIOD reported in Colombia and the first comprehensive characterization reported in the literature of a patient with homozygosity of the known variant c.1933C > T p.Arg645Cys. Conclusion: A severe phenotype of the disease with cerebrovascular involvement by homozygosity of the known variant c.1933C > T p.Arg645Cys in the SMARCAL1 gene can be expected.

Small vessel vasculitis, different renal outcomes in pediatric patients. Case reports

Vasculitis mainly affects the walls of the blood vessels, and is an uncommon disease in the pediatric population. In general, they are classified according to the EULAR / PreS consensus in children and in adults according to the Chapel-Hill consensus conference. ANCA-associated vasculitis (AAV) is part of small-vessel disease and is represented by granulomatosis with polyangiitis (GPA), eosinophilic granulomatosis with polyangiitis (EGPA), microscopic polyangiitis (MPA), and others. The representative renal histopathological findings are focal necrotizing glomerulonephritis with crescents, variable interstitial inflammation, absence of immune complexes, or small deposits of immunoglobulins. Clinically, AAV can manifest with hematuria, proteinuria, high blood pressure, and/or rapidly progressive glomerulonephritis. GPA can severely affect the kidney in 75% of cases. In MPA, renal involvement (75-90%) can be rapid and severe with the possibility of requiring renal replacement therapy in more than half of the patients. Furthermore, up to 25% of patients may have high blood pressure, and the mortality at one year can be up to 85%. In EGPA the renal involvement is usually mild. Three pediatric cases of AAV with different renal outcomes are presented, including the need for renal replacement therapy with the recovery of renal function, kidney transplantation, and death, followed in a fourth level of care institution in Colombia.

Las vasculitis, patologías cuyo hallazgo principal es la afectación de las paredes de los vasos sanguíneos, se presentan de forma infrecuente en la población pediátrica. En general, en niños se clasifican de acuerdo con el consenso de la EULAR/PReS, y en adultos, según la Conferencia de Consenso de Chapel-Hill. Las vasculitis asociadas con ANCA (VAA) hacen parte de las vasculitis de pequeños vasos y están representadas por la granulomatosis con poliangeítis (GPA), la granulomatosis eosinofílica con poliangeítis (EGPA) y la poliangeítis microscópica (PAM), entre otras. A nivel renal, los hallazgos histopatológicos representativos son la glomerulonefritis focal necrotizante con media luna, inflamación intersticial variable, ausencia de complejos inmunes o pequeños depósitos de inmunoglobulinas. Clínicamente, las VAA pueden manifestarse con hematuria, proteinuria, hipertensión arterial o glomerulonefritis rápidamente progresiva. La GPA puede afectar de forma severa el riñón en el 75% de los casos, mientras que, en la PAM, el compromiso renal (75-90%) puede ser rápido y severo con posibilidad de requerir terapia de reemplazo renal en más de la mitad de los pacientes. Además, hasta el 25% de los casos puede tener hipertensión arterial, con una mortalidad a un ario de 85%. En la EGPA, el compromiso renal suele ser leve. Se presentan 3 casos pediátricos de VAA con diferentes desenlaces renales, que incluyen necesidad de terapia de reemplazo renal con recuperación de función renal, trasplante renal y muerte, seguidas en una institución de IV nivel del suroccidente colombiano.

New PAX2 Mutation Associated with Polycystic Kidney Disease: A Case Report.

BACKGROUND: Congenital anomalies of the kidney and urinary tract (CAKUT) are the leading cause of end stage renal disease in children. Diagnosis by genetic testing has proven challenging due to its genetic and phenotypic heterogeneity, as well as incomplete penetrance. We report a case on a 16-months old female with a history of renal cysts and a PAX2 mutation. CASE PRESENTATION: The patient presented with a prenatal diagnosis of Potter sequence and a postnatal diagnosis of renal cysts. An ultrasound at 20 weeks gestation revealed right renal agenesis and possible left renal dysplasia. Post natal genetic analyses identified a novel mutation in PAX2. CONCLUSION: Cystic kidney disease is often underdiagnosed due to its variable expressivity and wide range of clinical manifestations; PAX2 genetic screening should be considered for all patients with CAKUT.

PHEX Gene Mutation in a Patient with X-Linked Hypophosphatemic Rickets in a Developing Country.

INTRODUCTION: X-linked hypophosphatemic rickets is part of a larger group of hereditary diseases characterized by renal phosphate loss, which causes growth disorders, rickets, and osteomalacia. These conditions are characterized by disorders in phosphate equilibrium, which is essential for bone formation. CASE REPORT: A female patient presented with bone deformities of the inferior extremities, prominent joints, and loss of teeth. She received initial management with oral calcium and orthotics in inferior extremities, with poor clinical outcome. PHEX gene sequencing revealed a pathogenic variant c.1601C>T (p.Pro534Leu). DISCUSSION: XLHR is caused by mutations in the PHEX gene; to date, more than 460 mutations have been associated with the disease. Clinically, it is characterized by bowing of the lower extremities, decreased growth, musculoskeletal complaints, dental abscesses, and other clinical signs and symptoms of rickets.