RESUMEN
BACKGROUND: Poland Syndrome (PS) is a rare congenital disorder presenting with agenesis/hypoplasia of the pectoralis major muscle variably associated with thoracic and/or upper limb anomalies. Most cases are sporadic, but familial recurrence, with different inheritance patterns, has been observed. The genetic etiology of PS remains unknown. Karyotyping and array-comparative genomic hybridization (CGH) analyses can identify genomic imbalances that can clarify the genetic etiology of congenital and neurodevelopmental disorders. We previously reported a chromosome 11 deletion in twin girls with pectoralis muscle hypoplasia and skeletal anomalies, and a chromosome six deletion in a patient presenting a complex phenotype that included pectoralis muscle hypoplasia. However, the contribution of genomic imbalances to PS remains largely unknown. METHODS: To investigate the prevalence of chromosomal imbalances in PS, standard cytogenetic and array-CGH analyses were performed in 120 PS patients. RESULTS: Following the application of stringent filter criteria, 14 rare copy number variations (CNVs) were identified in 14 PS patients in different regions outside known common copy number variations: seven genomic duplications and seven genomic deletions, enclosing the two previously reported PS associated chromosomal deletions. These CNVs ranged from 0.04 to 4.71 Mb in size. Bioinformatic analysis of array-CGH data indicated gene enrichment in pathways involved in cell-cell adhesion, DNA binding and apoptosis processes. The analysis also provided a number of candidate genes possibly causing the developmental defects observed in PS patients, among others REV3L, a gene coding for an error-prone DNA polymerase previously associated with Möbius Syndrome with variable phenotypes including pectoralis muscle agenesis. CONCLUSIONS: A number of rare CNVs were identified in PS patients, and these involve genes that represent candidates for further evaluation. Rare inherited CNVs may contribute to, or represent risk factors of PS in a multifactorial mode of inheritance.
Asunto(s)
Hibridación Genómica Comparativa/métodos , Variaciones en el Número de Copia de ADN , Redes Reguladoras de Genes , Cariotipificación/métodos , Síndrome de Poland/genética , Duplicación Cromosómica , Femenino , Predisposición Genética a la Enfermedad , Humanos , Masculino , Eliminación de SecuenciaRESUMEN
BACKGROUND: Poland Syndrome (PS) is a rare disorder characterized by hypoplasia/aplasia of the pectoralis major muscle, variably associated with thoracic and upper limb anomalies. Familial recurrence has been reported indicating that PS could have a genetic basis, though the genetic mechanisms underlying PS development are still unknown. CASE PRESENTATION: Here we describe a couple of monozygotic (MZ) twin girls, both presenting with Poland Syndrome. They carry a de novo heterozygous 126 Kbp deletion at chromosome 11q12.3 involving 5 genes, four of which, namely HRASLS5, RARRES3, HRASLS2, and PLA2G16, encode proteins that regulate cellular growth, differentiation, and apoptosis, mainly through Ras-mediated signaling pathways. CONCLUSIONS: Phenotype concordance between the monozygotic twin probands provides evidence supporting the genetic control of PS. As genes controlling cell growth and differentiation may be related to morphological defects originating during development, we postulate that the observed chromosome deletion could be causative of the phenotype observed in the twin girls and the deleted genes could play a role in PS development.
Asunto(s)
Deleción Cromosómica , Cromosomas Humanos Par 11 , Síndrome de Poland/genética , Gemelos Monocigóticos , Adolescente , Mama/anomalías , Hibridación Genómica Comparativa , Femenino , Deformidades Congénitas de la Mano , Humanos , Repeticiones de Microsatélite/genética , Fenotipo , Síndrome de Poland/diagnósticoRESUMEN
The metabotropic glutamate (mGlu) receptor 1 (GRM1) has been shown to play an important role in neuronal cells by triggering, through calcium release from intracellular stores, various signaling pathways that finally modulate neuron excitability, synaptic plasticity, and mechanisms of feedback regulation of neurotransmitter release. Herein, we show that Grm1 is expressed in glomerular podocytes and that a glomerular phenotype is exhibited by Grm1(crv4) mice carrying a spontaneous recessive inactivating mutation of the gene. Homozygous Grm1(crv4/crv4) and, to a lesser extent, heterozygous mice show albuminuria, podocyte foot process effacement, and reduced levels of nephrin and other proteins known to contribute to the maintenance of podocyte cell structure. Overall, the present data extend the role of mGlu1 receptor to the glomerular filtration barrier. The regulatory action of mGlu1 receptor in dendritic spine morphology and in the control of glutamate release is well acknowledged in neuronal cells. Analogously, we speculate that mGlu1 receptor may regulate foot process morphology and intercellular signaling in the podocyte.
Asunto(s)
Albuminuria/patología , Glomérulos Renales/patología , Receptores de Glutamato Metabotrópico/deficiencia , Albuminuria/complicaciones , Albuminuria/metabolismo , Animales , Western Blotting , Células Cultivadas , Doxorrubicina/farmacología , Técnica del Anticuerpo Fluorescente , Regulación de la Expresión Génica/efectos de los fármacos , Silenciador del Gen/efectos de los fármacos , Humanos , Corteza Renal/efectos de los fármacos , Corteza Renal/metabolismo , Corteza Renal/patología , Enfermedades Renales/complicaciones , Enfermedades Renales/metabolismo , Enfermedades Renales/patología , Glomérulos Renales/metabolismo , Glomérulos Renales/ultraestructura , Ratones , Fenotipo , Podocitos/efectos de los fármacos , Podocitos/metabolismo , Podocitos/patología , Receptores de Glutamato Metabotrópico/genética , Receptores de Glutamato Metabotrópico/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , TransfecciónRESUMEN
BACKGROUND: Interstitial 6q deletions, involving the 6q15q25 chromosomal region, are rare events characterized by variable phenotypes and no clear karyotype/phenotype correlation has been determined yet. RESULTS: We present a child with a 6q21q22.1 deletion, characterized by array-CGH, associated with developmental delay, intellectual disability, microcephaly, facial dysmorphisms, skeletal, muscle, and brain anomalies. DISCUSSION: In our patient, the 6q21q22.1 deleted region contains ten genes (TRAF3IP2, FYN, WISP3, TUBE1, LAMA4, MARCKS, HDAC2, HS3ST5, FRK, COL10A1) and two desert gene regions. We discuss here if these genes had some role in determining the phenotype of our patient in order to establish a possible karyotype/phenotype correlation.
RESUMEN
The metabotropic glutamate (mGlu) 1 receptor, coded by the GRM1 gene, is involved in synaptic activities, learning and neuroprotection. Eleven different mouse Grm1 mutations, either induced or spontaneously occurring, have been reported, including one from our group. All the mutations result in a complex phenotype with ataxia and intention tremor in mice. Moreover, autoantibodies against mGlu1 receptor have been associated with paraneoplastic cerebellar ataxia in humans. In spite of the large clinical and genetic heterogeneity displayed by the inherited forms of cerebellar ataxia, forms remain with a yet unknown molecular definition. With the evidence coming out from mouse models and from paraneoplastic ataxia, it seems that GRM1 represents a good candidate gene for early-onset ataxia forms, though no GRM1 mutations have thus far been looked for. The aim of this study was to investigate the possible involvement of GRM1 in early-onset or familial forms of ataxia. We searched for gene mutations in a panel of patients with early-onset ataxia as yet molecularly undefined. No causative mutations were found, though we detected synonymous variants in the exons and changes in flanking intronic sequences which are unlikely to alter correct splicing upon bioinformatics prediction. As for other known forms of inherited ataxias, absence of mutations in GRM1 seems to suggest a relatively low frequency in cerebellar ataxias.