RESUMEN
Congenital anomalies of the kidney and urinary tract (CAKUT) constitute one of the most frequent birth defects and represent the most common cause of chronic kidney disease in the first three decades of life. Despite the discovery of dozens of monogenic causes of CAKUT, most pathogenic pathways remain elusive. We performed whole-exome sequencing (WES) in 551 individuals with CAKUT and identified a heterozygous de novo stop-gain variant in ZMYM2 in two different families with CAKUT. Through collaboration, we identified in total 14 different heterozygous loss-of-function mutations in ZMYM2 in 15 unrelated families. Most mutations occurred de novo, indicating possible interference with reproductive function. Human disease features are replicated in X. tropicalis larvae with morpholino knockdowns, in which expression of truncated ZMYM2 proteins, based on individual mutations, failed to rescue renal and craniofacial defects. Moreover, heterozygous Zmym2-deficient mice recapitulated features of CAKUT with high penetrance. The ZMYM2 protein is a component of a transcriptional corepressor complex recently linked to the silencing of developmentally regulated endogenous retrovirus elements. Using protein-protein interaction assays, we show that ZMYM2 interacts with additional epigenetic silencing complexes, as well as confirming that it binds to FOXP1, a transcription factor that has also been linked to CAKUT. In summary, our findings establish that loss-of-function mutations of ZMYM2, and potentially that of other proteins in its interactome, as causes of human CAKUT, offering new routes for studying the pathogenesis of the disorder.
Asunto(s)
Proteínas de Unión al ADN/genética , Epigénesis Genética , Factores de Transcripción Forkhead/genética , Mutación , Proteínas Represoras/genética , Factores de Transcripción/genética , Sistema Urinario/metabolismo , Anomalías Urogenitales/genética , Proteínas Anfibias/antagonistas & inhibidores , Proteínas Anfibias/genética , Proteínas Anfibias/metabolismo , Animales , Estudios de Casos y Controles , Niño , Preescolar , Proteínas de Unión al ADN/metabolismo , Familia , Femenino , Factores de Transcripción Forkhead/metabolismo , Heterocigoto , Humanos , Lactante , Larva/genética , Larva/crecimiento & desarrollo , Larva/metabolismo , Masculino , Ratones , Ratones Noqueados , Morfolinos/genética , Morfolinos/metabolismo , Linaje , Unión Proteica , Proteínas Represoras/metabolismo , Factores de Transcripción/metabolismo , Sistema Urinario/anomalías , Anomalías Urogenitales/metabolismo , Anomalías Urogenitales/patología , Secuenciación del Exoma , XenopusRESUMEN
A previously healthy 1-year-old boy presented with a right lower eyelid abscess. Oral and topical antibiotics were initiated, and the lesion was drained and explored. Despite medical and surgical treatment, the abscess failed to resolve completely and formed again 1 month later. A second incision and drainage procedure was performed, and Candida albicans grew in cultures. Additional workup revealed severe neutropenia with an absolute neutrophil count of 0.18 k/µl (1.19-7.21 k/µl). The abscess resolved after 2 weeks of oral fluconazole. C. albicans eyelid abscess may be the presenting sign of systemic immunodeficiency.