RESUMEN
Pituitary hormone deficiency occurs in â¼1:4,000 live births. Approximately 3% of the cases are due to mutations in the alpha isoform of POU1F1, a pituitary-specific transcriptional activator. We found four separate heterozygous missense variants in unrelated individuals with hypopituitarism that were predicted to affect a minor isoform, POU1F1 beta, which can act as a transcriptional repressor. These variants retain repressor activity, but they shift splicing to favor the expression of the beta isoform, resulting in dominant-negative loss of function. Using a high-throughput splicing reporter assay, we tested 1,070 single-nucleotide variants in POU1F1. We identified 96 splice-disruptive variants, including 14 synonymous variants. In separate cohorts, we found two additional synonymous variants nominated by this screen that co-segregate with hypopituitarism. This study underlines the importance of evaluating the impact of variants on splicing and provides a catalog for interpretation of variants of unknown significance in POU1F1.
Asunto(s)
Ensayos Analíticos de Alto Rendimiento/métodos , Hipopituitarismo/patología , Mutación , Hormonas Hipofisarias/deficiencia , Empalme del ARN/genética , Factor de Transcripción Pit-1/genética , Adolescente , Adulto , Niño , Preescolar , Humanos , Hipopituitarismo/etiología , Hipopituitarismo/metabolismo , Masculino , LinajeRESUMEN
The anterior pituitary gland is comprised of specialized cell-types that produce and secrete polypeptide hormones in response to hypothalamic input and feedback from target organs. These specialized cells arise during embryonic development, from stem cells that express SOX2 and the pituitary transcription factor PROP1, which is necessary to establish the stem cell pool and promote an epithelial to mesenchymal-like transition, releasing progenitors from the niche. Human and mouse embryonic stem cells can differentiate into all major hormone-producing cell types of the anterior lobe in a highly plastic and dynamic manner. More recently human induced pluripotent stem cells (iPSCs) emerged as a viable alternative due to their plasticity and high proliferative capacity. This mini-review gives an overview of the major advances that have been achieved to develop protocols to generate pituitary hormone-producing cell types from stem cells and how these mechanisms are regulated. We also discuss their application in pituitary diseases, such as pituitary hormone deficiencies.
Asunto(s)
Diferenciación Celular/fisiología , Células Madre Pluripotentes Inducidas/fisiología , Células Madre Pluripotentes Inducidas/trasplante , Hipófisis/fisiología , Hipófisis/trasplante , Medicina Regenerativa/métodos , Animales , Humanos , Células Madre Pluripotentes Inducidas/citología , Enfermedades de la Hipófisis/patología , Enfermedades de la Hipófisis/terapia , Hipófisis/citología , Medicina Regenerativa/tendenciasRESUMEN
A historical summary of genetics and genomic medicine in Argentina. We go through the achievements and difficulties in the implementation of genetic and genomic services both in academia and health care.
RESUMEN
BACKGROUND: Congenital Hypopituitarism is caused by genetic and environmental factors. Over 30 genes have been implicated in isolated and/or combined pituitary hormone deficiency. The etiology remains unknown for up to 80% of the patients, but most cases have been analyzed by limited candidate gene screening. Mutations in the PROP1 gene are the most common known cause, and the frequency of mutations in this gene varies greatly by ethnicity. We designed a custom array to assess the frequency of mutations in known hypopituitarism genes and new candidates, using single molecule molecular inversion probes sequencing (smMIPS). METHODS: We used this panel for the first systematic screening for causes of hypopituitarism in children. Molecular inversion probes were designed to capture 693 coding exons of 30 known genes and 37 candidate genes. We captured genomic DNA from 51 pediatric patients with CPHD (n = 43) or isolated GH deficiency (IGHD) (n = 8) and their parents and conducted next generation sequencing. RESULTS: We obtained deep coverage over targeted regions and demonstrated accurate variant detection by comparison to whole-genome sequencing in a control individual. We found a dominant mutation GH1, p.R209H, in a three-generation pedigree with IGHD. CONCLUSIONS: smMIPS is an efficient and inexpensive method to detect mutations in patients with hypopituitarism, drastically limiting the need for screening individual genes by Sanger sequencing.