Cognitive profile and disorders affecting higher brain functions in paediatric patients with neurofibromatosis type 1. / Pacientes con neurofibromatosis tipo 1: perfil cognitivo y trastornos en funciones cerebrales superiores en la edad pediátrica.

INTRODUCTION: Neurofibromatosis type 1 (NF1) is a common neurocutaneous syndrome often associated with specific cognitive deficits that are rarely monitored during follow-up of these patients. OBJECTIVE: The purpose of our study is two-fold. First, we aimed to describe the cognitive profile of patients with NF1 and detect disorders in higher brain functions associated with the disease. Second, we identified the reasons for consultation associated with school performance in these patients. METHODS: We conducted a descriptive cross-sectional study of 24 paediatric patients (ages 5 to 16) with NF1 who underwent neuropsychological assessment. RESULTS: The most frequent reasons for consultation were attention deficits (58.33%), learning disorders (25%), poor motor coordination (25%), and language impairment (0.8%). Although 96% of the patients displayed impairments in at least one of the assessed areas, only 83.34% of the parents had reported such impairments. Attention-deficit/hyperactivity disorder was present in 58.33% of the patients, whereas 33.33% had nonverbal learning disabilities, 20.83% had expressive language disorder, 8.33% had borderline intellectual functioning, 4.16% had mental retardation, and only 4.16% showed no cognitive impairment. CONCLUSION: Higher brain functions are frequently impaired in paediatric patients with NF1. Although many parents report such disorders, they can go undetected in some cases. Neuropsychological assessment is recommended for all paediatric patients with NF1 to detect cognitive impairment and provide early, effective rehabilitation treatment.

Transcriptional regulation of the ferritin heavy-chain gene: the activity of the CCAAT binding factor NF-Y is modulated in heme-treated Friend leukemia cells and during monocyte-to-macrophage differentiation.

The ferritin H-chain gene promoter regulation was analyzed in heme-treated Friend leukemia cells (FLCs) and during monocyte-to-macrophage differentiation. In the majority of cell lines studied, the regulation of ferritin expression was exerted mostly at the translational level. However, in differentiating erythroid cells, which must incorporate high levels of iron to sustain hemoglobin synthesis, and in macrophages, which are involved in iron storage, transcriptional regulation seemed to be a relevant mechanism. We show here that the minimum region of the ferritin H-gene promoter that is able to confer transcriptional regulation by heme in FLCs to a reporter gene is 77 nucleotides upstream of the TATA box. This cis element binds a protein complex referred to as HRF (heme-responsive factor), which is greatly enhanced both in heme-treated FLCs and during monocyte-to-macrophage differentiation. The CCAAT element present in reverse orientation in this promoter region of the ferritin H-chain gene is necessary for binding and for gene activity, since a single point mutation is able to abolish the binding of HRF and the transcriptional activity in transfected cells. By competition experiments and supershift assays, we identified the induced HRF as containing at least the ubiquitous transcription factor NF-Y. NF-Y is formed by three subunits, A, B, and C, all of which are necessary for DNA binding. Cotransfection with a transdominant negative mutant of the NF-YA subunit abolishes the transcriptional activation by heme, indicating that NF-Y plays an essential role in this activation. We have also observed a differential expression of the NF-YA subunit in heme-treated and control FLCs and during monocyte-to-macrophage differentiation.

[Angiokeratoma corporis diffusum (Fabry's disease). Update. Apropos of 2 cases]. / Angioqueratoma "corporis diffusum" (enfermedad de Fabry). Actualización. Apropós de dos casos.

Fabry's disease (angiokeratoma corporis diffusum) is an X-linked recessive inherited metabolic defect due to the lack of the enzyme alpha-galactosidase A. We reviewed the Argentine literature on the subject, the main features of the disease and its differential diagnosis. Two patients aged ten and fifteen are described showing the characteristic clinical picture of the disease since ages four and nine respectively. Skin and conjunctival ultrastructural studies showed intracytoplasmatic granules with a lamellar appearance in the endothelial cells, pericytes and fibroblasts. Plasma levels of alpha-galactosidase activity were sharply decreased in the two patients studied and partially decreased in their heterozygous mothers.

Identification of 17 novel mutations in 40 Argentinean unrelated families with mucopolysaccharidosis type II (Hunter syndrome).

Mucopolysaccharidosis type II (MPSII) is an X-linked lysosomal storage disorder caused by deficiency of the enzyme iduronate-2-sulfatase (IDS). The human IDS gene is located in chromosome Xq28. This is the first report of genotype and phenotype characterization of 49 Hunter patients from 40 families of Argentina. Thirty different alleles have been identified, and 57% were novel. The frequency of de novo mutations was 10%. Overall, the percentage of private mutations in our series was 75%.

Cells resistant to interferon-beta respond to interferon-gamma via the Stat1-IRF-1 pathway.

The mechanism responsible for the induction of the 2-5A synthetase gene by Interferon-gamma (IFN-gamma) (type II) was studied in Friend leukemia cells. It was previously shown that activation of 2-5A synthetase gene expression by IFN-gamma in the 3Cl8 cell, a clone resistant to IFN-alpha,beta (type I), correlates with the formation of two major complexes, designated Fg and Fc, that bind to the interferon-stimulated responsive element of the gene. Conversely, in a clone resistant to both types of IFNs (3 gamma R8), no induction of DNA-protein complexes or of 2-5A synthetase gene expression was detected. In the present report the Fg complex has been characterized as including the interferon regulatory factor 1 (IRF-1), whereas the Fc factor, present also in control cells, has been characterized as composed of IRF-2. Incubation of cell extracts with antibodies to IRF-1 abolishes the formation of the Fg complex, and antibodies to IRF-2 abolish the formation of the Fc complex. Moreover, in the 3Cl8 cell, IFN-gamma is able to induce in few minutes the formation of a complex between a DNA element identified as the IFN-gamma activation site (GAS), present on the IRF-1 gene promoter, and the STAT1 protein. These findings suggest that in cells resistant to type I IFN, IFN-gamma is able, through the activation of the STAT1 protein, to induce the expression of the IRF-1 factor which in turn seems to be sufficient to transactivate the 2-5A synthetase gene.

The activity of the CCAAT-box binding factor NF-Y is modulated through the regulated expression of its A subunit during monocyte to macrophage differentiation: regulation of tissue-specific genes through a ubiquitous transcription factor.

In this study, we analyzed the regulation of NF-Y expression during human monocyte to macrophage maturation. NF-Y is a ubiquitous and evolutionarily conserved transcription factor that binds specifically to the CCAAT motif present in the 5' promoter region of a wide variety of genes. We show here that in circulating monocytes, NF-Y binding activity is not detected on the CCAAT motif present in the promoters of genes such as major histocompatibility complex (MHC) class II, gp91-phox, mig, and fibronectin, whereas during macrophage differentiation, a progressive increase in NF-Y binding activity is observed on these promoters. Analysis of NF-Y subunit expression indicates that the absence of NF-Y activity in circulating monocytes is caused by a lack of the A subunit. Furthermore, addition of the recombinant NF-YA subunit restores NF-Y binding. We show that the lack of NF-YA protein is due to posttranscriptional regulation and not to a specific proteolytic activity. In fact, NF-YA mRNA is present at the same level at all days of monocyte cultivation, whereas the protein is absent in freshly isolated monocytes but is progressively synthesized during the maturation process. We thus conclude that the NF-YA subunit plays a relevant role in activating transcription of genes highly expressed in mature monocytes. In line with this conclusion, we show that the cut/CDP protein, a transcriptional repressor that inhibits gpc91-phox gene expression by preventing NF-Y binding to the CAAT box, is absent in monocytes.

Hipomelanosis de Ito: estudio con microscopía electrónica / Hypomelanosis of Ito: study with electronic microscopy

Se presenta un niño de 10 años de edad con lesiones musculosas dispuestas en arabescos y arremolinadas en tórax; lineales en miembros superiores e inferiores. Esta coexisten con afectación de SNC y compromiso óseo, dentario y ocular, constituyendo el cuadro de Hipomelanosis de Ito. Se efectúa microscopía electrónica para confirmar el diagnóstico. Se hace referencia a características clínicas y evolutivas, puntualizando las diferencias con otros síntomas neurocutáneos