Fenotipos inesperados en el síndrome de Alport: la necesidad del estudio genético / Unexpected phenotypes in Alport syndrome: the need for genetic testing

El diagnóstico del síndrome de Alport supone un reto en la edadpediátrica, debido a la ausencia de fenotipos clínicos esperados de la enfermedad, su clásica caracterización de entidad rara y la práctica muy restringida de biopsias renales con análisis rutinario de la muestra por microscopía electrónica durante la infancia. Se presentan las características clínicas y genéticas de 6 pacientes pediátricos (4 mujeres) diagnosticados de síndromede Alport en dos centros hospitalarios entre 2018 y 2021. Todos los pacientes presentaron un debut clínico claramente diferente y ninguno presentó complicaciones auditivas nioftalmológicas. La mitad carecía de antecedentes familiares de enfermedad renal crónica. Ninguna biopsia renal realizada confirmó el diagnóstico. Todos los pacientes fueron confirmadosgenéticamente y fueron el caso índice del estudio familiar. Esta serie ilustra la presencia de fenotipos clínicos inesperados en el síndrome de Alport y refleja la necesidad de incorporar el estudio genético para su diagnóstico.

The diagnosis of Alport syndrome is a challenge in the pediatric age, due to the absence of expected clinical phenotypes of the disease, its classic characterization of a rare disease and the very restricted practice of renal biopsies with routine analysis of the sample by electron microscopy during infancy. The clinical and genetic characteristics of 6 pediatric patients (4 women) diagnosed with Alport syndrome in two hospital centers between 2018 and 2021 are reported. All patients presented a clearly different clinical debut and none presented auditory or ophthalmological complications. Half had no family history of chronic kidney disease. No kidney biopsy performed confirmed the diagnosis. All patients were genetically confirmed and were the index case in the family study. This series illustrates the presence of unexpected clinical phenotypes in Alport syndrome and reflects the need for the incorporation of the genetic study for its diagnosis.

[Unexpected phenotypes in Alport syndrome: the need for genetic testing]. / Fenotipos inesperados en el síndrome de Alport: la necesidad del estudio genético.

The diagnosis of Alport syndrome is a challenge in the pediatric age, due to the absence of expected clinical phenotypes of the disease, its classic characterization of a rare disease and the very restricted practice of renal biopsies with routine analysis of the sample by electron microscopy during infancy. The clinical and genetic characteristics of 6 pediatric patients (4 women) diagnosed with Alport syndrome in two hospital centers between 2018 and 2021 are reported. All patients presented a clearly different clinical debut and none presented auditory or ophthalmological complications. Half had no family history of chronic kidney disease. No kidney biopsy performed confirmed the diagnosis. All patients were genetically confirmed and were the index case in the family study. This series illustrates the presence of unexpected clinical phenotypes in Alport syndrome and reflects the need for the incorporation of the genetic study for its diagnosis.

El diagnóstico del síndrome de Alport supone un reto en la edad pediátrica, debido a la ausencia de fenotipos clínicos esperados de la enfermedad, su clásica caracterización de entidad rara y la práctica muy restringida de biopsias renales con análisis rutinario de la muestra por microscopía electrónica durante la infancia. Se presentan las características clínicas y genéticas de 6 pacientes pediátricos (4 mujeres) diagnosticados de síndrome de Alport en dos centros hospitalarios entre 2018 y 2021. Todos los pacientes presentaron un debut clínico claramente diferente y ninguno presentó complicaciones auditivas ni oftalmológicas. La mitad carecía de antecedentes familiares de enfermedad renal crónica. Ninguna biopsia renal realizada confirmó el diagnóstico. Todos los pacientes fueron confirmados genéticamente y fueron el caso índice del estudio familiar. Esta serie ilustra la presencia de fenotipos clínicos inesperados en el síndrome de Alport y refleja la necesidad de incorporar el estudio genético para su diagnóstico.

Whole-Exome Sequencing (WES) results of 50 patients with chronic kidney diseases: a perspective of Alport syndrome.

OBJECTIVE: Chronic kidney disease (CKD) remains one of the major common health problems, and the number of people affected by the disease is progressively increasing in Turkey and worldwide. This study aimed to investigate molecular defects in Alport syndrome (AS) and other genes in patients with clinically suspected CKD using whole-exome sequencing (WES). METHODS: Patients with clinical suspicion of CKD were included in the study. Molecular genetic analyses were performed on genomic DNA by using WES. RESULTS: A total of 15 with 5 different pathogenic or likely pathogenic variants were identified in CKD patients, with a diagnostic rate of 30%. Eight variants of uncertain significance were also detected. In this study, 10 variants were described for the first time. As a result, we detected variants associated with CKD in our study population and found AS as the most common CKD after other related kidney diseases. CONCLUSIONS: Our results suggest that in heterogeneous diseases such as CKD, WES analysis enables accurate identification of underlying molecular defects promptly. Although CKD accounts for 10-14% of all renal dysfunction, molecular genetic diagnosis is necessary for optimal long-term treatment, prognosis, and effective genetic counseling. .

Alport Syndrome: A Comprehensive Review on Genetics, Pathophysiology, Histology, Clinical and Therapeutic Perspectives.

BACKGROUND: Alport syndrome (AS) is a disease caused by mutations in COL4A3, COL4A4 or COL4A5, the genes that encode distinct chains of type IV collagen. The vast majority of cases present as an inherited disorder, although de novo mutations are present in around 10% of the cases. METHODS: This non-systematic review summarizes recent evidence on AS. We discuss the genetic and pathophysiology of AS, clinical manifestations, histopathology, diagnostic protocols, conventional treatment and prognostic markers of the disease. In addition, we summarize experimental findings with novel therapeutic perspectives for AS. RESULTS: The deficient synthesis of collagen heterotrimers throughout the organism leads to impaired basement membranes (BM) in several organs. As a result, the disease manifests in a wide range of conditions, particularly renal, ocular and auricular alterations. Moreover, leiomyomatosis and vascular abnormalities may also be present as atypical presentations. In this framework, diagnosis can be performed based on clinical evaluation, skin or renal biopsy and genetic screening, the latter being the gold standard. There are no formally approved treatments for AS, even though therapeutic options have been described to delay disease progression and increase life expectancy. Novel therapeutic targets under pre-clinical investigation included paricalcitol, sodium-glucose co-transporter- 2 inhibitors, bardoxolone methyl, anti-microRNA-21 oligonucleotides, recombinant human pentraxin-2, lysyl oxidase-like-2 blockers, hydroxypropyl-b-cyclodextrin, sodium 4-phenylbutyrate and stem cell therapy. CONCLUSION: AS is still a greatly under and misdiagnosed disorder. The pathophysiology is still not fully understood and genetics of the disease also have some gaps. Up to know, there is no specific and effective treatment for AS. Further studies are necessary to establish novel and effective therapeutic protocols.

Optical coherence tomography angiography findings in patients with Alport syndrome / Alterações encontradas na angiografia por tomografia de coerência óptica (OCT-A) em pacientes com síndrome de Alport

ABSTRACT Purpose: To describe the findings on optical coherence tomography angiography associated with Alport syndrome. Methods: Descriptive study from a referral ophthalmology service (Hospital Evangélico de Vila Velha, Brazil). Patients diagnosed with Alport syndrome were included. Results: The study group consisted of four patients (one female and three males) diagnosed with Alport syndrome. Visual acuity in the worst eye was between 20/40 and 20/60. All male patients had anterior lenticonus on biomicroscopy. The observed retinal findings included dots and flecks and pigmentary changes in the macula. On optical coherence tomography angiography, the inner retinal layers of all patients displayed thinning (especially in the temporal quadrant of the macula) and an increase in the foveal avascular zone. A thick choroid was observed in both eyes of the two youngest patients. Conclusions: In patients with Alport syndrome, the inner retinal layers suffer changes due to type IV collagen mutations. Optical coherence tomography angiography makes it possible to visualize and document these findings, making it a useful tool in the detection of early retinal findings associated with Alport syndrome.

RESUMO Objetivos: Descrever os achados na angiografia por tomografia de coerência óptica associada à síndrome de Alport. Métodos: Estudo descritivo de um serviço de referência em Oftalmologia (Hospital Evangélico de Vila Velha, Brasil). Os pacientes diagnosticados com síndrome de Alport, foram incluídos. Resultados: O grupo de estudo foi composto por quatro pacientes (um feminino e três homens) com diagnóstico de síndrome de Alport. A acuidade visual no pior olho estava entre 20/40 a 20/60. Todos os pacientes do sexo masculino apresentaram lenticone anterior à biomiscroscopia. Os achados da retina observados incluíram pontos e manchas e alterações pigmentares na mácula. Na angiotomografia de coerência óptica, as camadas internas da retina de todos os pacientes apresentaram afinamento (especialmente na região temporal da mácula) e aumento da zona avascular foveal. Uma coroide espessa foi observada em ambos os olhos dos dois pacientes mais jovens. Conclusões: Em pacientes com síndrome de Alport, as camadas internas da retina sofrem alterações devido à mutação do colágeno tipo IV. A angiotomografia de coerência óptica permite visualizar esses achados, tornando-o uma ferramenta útil na detecção de achados iniciais da retina associados à síndrome de Alport.

Optical coherence tomography angiography findings in patients with Alport syndrome.

PURPOSE: To describe the findings on optical coherence tomography angiography associated with Alport syndrome. METHODS: Descriptive study from a referral ophthalmology service (Hospital Evangélico de Vila Velha, Brazil). Patients diagnosed with Alport syndrome were included. RESULTS: The study group consisted of four patients (one female and three males) diagnosed with Alport syndrome. Visual acuity in the worst eye was between 20/40 and 20/60. All male patients had anterior lenticonus on biomicroscopy. The observed retinal findings included dots and flecks and pigmentary changes in the macula. On optical coherence tomography angiography, the inner retinal layers of all patients displayed thinning (especially in the temporal quadrant of the macula) and an increase in the foveal avascular zone. A thick choroid was observed in both eyes of the two youngest patients. CONCLUSIONS: In patients with Alport syndrome, the inner retinal layers suffer changes due to type IV collagen mutations. Optical coherence tomography angiography makes it possible to visualize and document these findings, making it a useful tool in the detection of early retinal findings associated with Alport syndrome.

[Alport syndrome. Report of two cases]. / Repercusiones oculares del Síndrome de Alport: A propósito de dos casos.

Alport syndrome is an inherited progressive form of glomerular disease that is often associated with sensorineural hearing loss and ocular abnormalities. We report two men with Alport syndrome. Both had chronic kidney disease and consulted for long-term loss of visual acuity. One had auditory abnormalities. On the ophthalmological examination, both had anterior lenticonus and one had dot or fleck retinopathy. Those findings are described in up to 50% and 70% of men with X-linked Alport syndrome, respectively. Both patients had a family history of Alport syndrome or suggestive signs and symptoms.

Una nueva variante del gen COL4A4 (c.1856G> A). De un caso de glomeruloesclerosis focal y segmentaria a una familia con síndrome de Alport / A novel COL4A4 gene variant (c.1856G>A): from a focal segmental glomerulosclerosis case to a family with Alport syndrome

El síndrome de Alport (SA), también conocido como nefritis hereditaria, es una forma progresiva hereditaria de enfermedad glomerular que a menudo se asocia con pérdida auditiva neurosensorial y anomalías oculares. Es causada por mutaciones en los genes que codifican varios miembros de las proteínas de colágeno del tipo IV, que se hallan en las membranas basales principalmente. Los análisis genéticos de las familias afectadas han identificado cuatro modos diferentes de transmisión en pacientes con síndrome de Alport. La forma del síndrome ligada al X surge a partir de mutaciones de COL4A5 y COL4A6 en el cromosoma X, mientras que las formas autosómicas resutan de defectos genéticos tanto en el gen COL4A3 como en el COL4A4, en el cromosoma 2q35-37. Las formas digénicas incluyen pacientes con mutaciones coexistentes en COL4A3, COL4A4 y COL4A5. El resultado clínico a largo plazo en pacientes con SA con mutaciones heterocigotas de COL4A3/A4es generalmente impredecible. La glomeruloesclerosis focal y segmentaria suele desarrollarse en el SA clásico en etapas posteriores y se presenta predominantemente con proteinuria asociada con hematuria. En el caso índice presentado en este informe, a un hombre de 26 años se le realizó una biopsia de riñón debido a una proteinuria nefrótica y una hematuria microscópica acompañada de una función renal alterada. Se le diagnosticó glomeruloesclerosis focal y segmentaria. Debido a que tenía una pérdida auditiva progresiva desde el inicio del estudio, se le realizó un estudio genético de mutaciones en los genes COL4A3 y COL4A4. Se detectó una nueva mutación en el gen COL4A4 (c.1804-7T> C).Debido a que sus padres tenían un matrimonio consanguíneo, el resto de la familia fue sometida a estudio para la misma variante. Sus padres y su hermana fueron heterocigotos y homocigota para la misma variante, respectivamente. En este estudio, se demostró la existencia de una familia con síndrome de Alport con una nueva mutación en el gen COL4A4 (c.1856G> A) que, según sabemos, es el primer caso reportado.

Alport syndrome, also known as hereditary nephritis, is an inherited progressive form of glomerular disease that is often associated with sensorineural hearing loss and ocular abnormalities. It is caused by mutations in genes encoding several members of type IV colagen proteins primarily found in basement membranes. Genetic analyses of affected families have identified four different modes of transmission in patients with Alport syndrome. X-linked form of the syndrome arises from mutations of COL4A5 and COL4A6 on chromosome X, whereas autosomal forms result from genetic defects in either the COL4A3 or COL4A4 genes at chromosome 2q35-37. Digenic forms include patients with coexisting mutations in COL4A3, COL4A4, and COL4A5. The long-term clinical outcome in AS patients with heterozygous COL4A3/A4 mutations is generally unpredictable. Focal segmental glomerulosclerosis usually develops in classical AS at later stages and presents predominantly with proteinuria associated with hematuria. The index case presented in this report, a 26-year-old man, had kidney biopsy because of nephrotic proteinuria and microscopic hematuria accompanied by impaired renal function. He diagnosed focal segmental glomerulosclerosis. As he had progressive hearing loss since chidhood we conducted a genetic study for mutations in COL4A3 and COL4A4 genes. A novel mutation in COL4A4 gene (c.1804-7T>C) was detected. As his parents had consanguineous marriage we investigated the rest of the family for the same variant. His parents, and his sister were found to be heterozygote, and homozygote for the same variant, respectively. In this report we demonstrated an Alport syndrome family with a novel mutation in COL4A4 gene (c.1856G>A) that has been first reported to our best knowledge.

Nefritis intersticial aguda inducida por rifampicina en un paciente con tuberculosis pulmonar / Rifampicin-induced acute interstitial nephritis in a patient with pulmonary tuberculosis

La tuberculosis (TB) constituye un grave problema de salud en el mundo y está relacionada con problemáticas sociales que dificultan su control y erradicación como la pobreza, la marginalidad y el hacinamiento. Aunque la toxicidad hepática por rifampicina es bien conocida, la nefrotoxicidad es una complicación poco frecuente y grave del tratamiento antituberculosis. El deterioro de la función renal, determinado por nefritis tubulointersticial aguda o necrosis tubular aguda o ambos, por lo general aparece en pacientes que reciben tratamiento intermitente; no obstante, algunos autores han informado casos ocurridos durante la terapia continua con rifampicina.Con frecuencia la lesión renal aguda inducida por rifampicina tiene un curso favorable con tratamiento y una recuperación completa de la función renal en un lapso de tres meses. El siguiente reporte describe un paciente en tratamiento por TB Pulmonar, que desarrolló toxicidad renal inducida por rifampicina

Repercusiones oculares del Síndrome de Alport: A propósito de dos casos / Alport syndrome. Report of two cases

Alport syndrome is an inherited progressive form of glomerular disease that is often associated with sensorineural hearing loss and ocular abnormalities. We report two men with Alport syndrome. Both had chronic kidney disease and consulted for long-term loss of visual acuity. One had auditory abnormalities. On the ophthalmological examination, both had anterior lenticonus and one had dot or fleck retinopathy. Those findings are described in up to 50% and 70% of men with X-linked Alport syndrome, respectively. Both patients had a family history of Alport syndrome or suggestive signs and symptoms.

Síndrome de alport: reporte de un caso / Alport syndrome: Case report

El síndrome de Alport (SA) es un conjunto de enfermedades que se caracterizan por una afección hereditaria de la membrana basal glomerular con alteraciones en el colágeno tipo IV que la compone. Se presenta con hematuria micro- o macroscópica; además, suele asociarse a alteraciones auditivas y oculares, y es causa de alrededor de 0.3 a 3% de la enfermedad renal terminal en pediatría.Se reporta el caso de adolescente de 14 años, sexo masculino, que consultó por presentar fiebre, debilidad generalizada y palidez de tres días de evolución. Tenía historia de leucocoria en ojo derecho desde el nacimiento, antecedentes familiares de hematuria (padre y hermano), además hipoacusia en oído derecho. Esto sumado a la lesión ocular antes descrita y a insuficiencia renal crónica se sospechó SA, por lo que se le realizó una audiometría y un ultrasonido (USG) ocular los cuales reportaban una hipoacusia de oído derecho y condensaciones vítreas en ojo derecho respectivamente; dada la hematuria familiar y propia del paciente se realizó el diagnóstico de Síndrome de Alport según los criterios de Flinter...(AU)

Female Patient with Alport Syndrome and Concomitant Membranous Nephropathy: Susceptibility or Association of Two Diseases?

Alport syndrome (AS) is a disorder of collagen IV, a component of glomerular basement membrane (GBM). The association of AS and immunocomplex nephropathies is uncommon. This is a case of a 37-year-old woman with family history of X-linked AS, including 4 affected sons. This patient developed full-blown nephrotic syndrome along a 3-month period, a presentation not consistent with AS progression. This scenario suggested an alternative diagnosis. A kidney biopsy was therefore performed, showing membranous nephropathy (MN) in addition to GBM structural alterations compatible with AS. Whole exome sequencing also confirmed the diagnosis of X-linked AS, revealing a heterozygous pathogenic mutation in COL4A5. While a negative serum anti-phospholipase A2 receptor did not rule out a primary form of MN, it was also uncertain whether positive serologic tests for syphilis could represent a secondary factor. It is currently unknown whether this unusual association represents AS susceptibility to immunocomplex-mediated diseases or simply an association of 2 disorders.

Posterior polymorphous corneal dystrophy in X linked Alport syndrome / Distrofia corneana polimorfa posterior em Síndrome de Alport

ABSTRACT We describe a six-year-old boy with a history of hematuria, posterior polymorphous corneal dystrophy and dots and fleck retinopathy. Alport syndrome should be ruled out in patients presenting with posterior polymorphous corneal dystrophy or anterior lenticonus and a family history of renal disease.

RESUMO Descrevemos um paciente de 6 anos de idade com história de hematúria, distrofia corneana polimorfa posterior e retinopatia em "dots and flecks". Síndrome de Alport deve ser excluída se o paciente apresentar com distrofia corneana polimorfa posterior ou lenticone anterior com historia familiar de doença renal.

Contact lens fitting in a patient with Alport syndrome and posterior polymorphous corneal dystrophy: a case report.

Alport Syndrome is a hereditary disease that is caused by a gene mutation and affects the production of collagen in basement membranes; this condition causes hemorrhagic nephritis associated with deafness and ocular changes. The X-linked form of this disease is the most common and mainly affects males. Typical ocular findings are dot-and-fleck retinopathy, anterior lenticonus, and posterior polymorphous corneal dystrophy. Some cases involving polymorphous corneal dystrophy and corneal ectasia have been previously described. Here we present a case report of a 33-year-old female with Alport syndrome, posterior polymorphous corneal dystrophy, and irregular astigmatism, whose visual acuity improved with a rigid gas permeable contact lens.

Contact lens fitting in a patient with Alport syndrome and posterior polymorphous corneal dystrophy: a case report / Adaptação de lentes de contato em paciente com síndrome de Alport e distrofia polimorfa posterior: relato de caso

ABSTRACT Alport Syndrome is a hereditary disease that is caused by a gene mutation and affects the production of collagen in basement membranes; this condition causes hemorrhagic nephritis associated with deafness and ocular changes. The X-linked form of this disease is the most common and mainly affects males. Typical ocular findings are dot-and-fleck retinopathy, anterior lenticonus, and posterior polymorphous corneal dystrophy. Some cases involving polymorphous corneal dystrophy and corneal ectasia have been previously described. Here we present a case report of a 33-year-old female with Alport syndrome, posterior polymorphous corneal dystrophy, and irregular astigmatism, whose visual acuity improved with a rigid gas permeable contact lens.

RESUMO A síndrome de Alport é descrita como uma doença hereditária que afeta um gene relacionado à produção de colágeno das membranas basais causando nefrite hemorrágica associada com surdez e alterações oculares. A forma ligada ao X é a mais comum e afeta principalmente homens. Os achados oculares típicos são retinopatia em ponto-mancha, lenticone anterior e distrofia polimorfa posterior. Alguns casos foram descritos de associação entre a distrofia polimorfa posterior e ectasia corneana. Nós apresentamos um caso de paciente do sexo feminino, 33 anos, diagnóstico de síndrome de Alport, distrofia polimorfa posterior e astigmatismo irregular, que apresenta melhora da acuidade visual após adaptação com lentes de contato rígidas gás permeáveis.