The Photoreceptor Cell-Specific Nuclear Receptor Gene (PNR ) Accounts for Retinitis Pigmentosa in the Crypto-Jews from Portugal (Marranos), Survivors from the Spanish Inquisition

The last Crypto-Jews (Marranos) are the survivors of Spanish Jews who were persecuted in the late fifteenth century, escaped to Portugal and were forced to convert to save their lives. Isolated groups still exist in mountainous areas such as Belmonte in the Beira-Baixa province of Portugal. We report here the genetic study of a highly consanguineous endogamic population of Crypto-Jews of Belmonte affected with autosomal recessive retinitis pigmentosa (RP). A genome-wide search for homozygosity allowed us to localize the disease gene to chromosome 15q22-q24 (Zmax=2.95 at θ=0 at the D15S131 locus). Interestingly, the photoreceptor cell-specific nuclear receptor (PNR) gene, the expression of which is restricted to the outer nuclear layer of retinal photoreceptor cells, was found to map to the YAC contig encompassing the disease locus. A search for mutations allowed us to ascribe the RP of Crypto-Jews of Belmonte to a homozygous missense mutation in the PNR gene. Preliminary haplotype studies support the view that this mutation is relatively ancient but probably occurred after the population settled in Belmonte.

Coreceptor Usage by HIV-1 and HIV-2 Primary Isolates: The Relevance of CCR8 Chemokine Receptor as an Alternative Coreceptor

The human immunodeficiency virus replication cycle begins by sequential interactions between viral envelope glycoproteins with CD4 molecule and a member of the seven-transmembrane, G-protein-coupled, receptors' family (coreceptor). In this report we focused on the contribution of CCR8 as alternative coreceptor for HIV-1 and HIV-2 isolates. We found that this coreceptor was efficiently used not only by HIV-2 but particularly by HIV-1 isolates. We demonstrate that CXCR4 usage, either alone or together with CCR5 and/or CCR8, was more frequently observed in HIV-1 than in HIV-2 isolates. Directly related to this is the finding that the non-usage of CXCR4 is significantly more common in HIV-2 isolates; both features could be associated with the slower disease progression generally observed in HIV-2 infected patients. The ability of some viral isolates to use alternative coreceptors besides CCR5 and CXCR4 could further impact on the efficacy of entry inhibitor therapy and possibly also in HIV pathogenesis.

Anticorpos Anti-Receptor da TSH na Doença de Graves

Neste trabalho os AA avaliam a sensibilidade, especificidade e valor predictivo do doseamen to dos anticorpos anti-receptor da TSH (TRAb) no diagnóstico da doença de Graves. A população estudada incluiu 80 doentes com doença de Graves recentemente diagnosticada e sem tratamento prévio (grupo 1), 63 doentes com outras patologias tiroideias (grupo II) e 60 indivíduos sem patologia tiroideia (grupo III). Utilizaram uma técnica de radioreceptor, o kit TRAK Henning, que considera positividade> 14 U TRAb L, negatividade 9 e zona cinzenta entre estes 2 valores. No grupo 1, 11 doentes tinham TRAb negativo e 7 situavam-se na zona cinzenta. No grupo II apenas 2 doentes tinham TRAb de 9 e todos os indivíduos do grupo controlo tinham TRAb negativo. Para efeito estatístico foram excluidos os doentes com valores na zona cinzenta. Os valores de sensibilidade e especificidade para o método ensaiado foram respectivamente de 84,5° o e 10000. O valor predictivo foi de 1000 o, o que permite afirmar com segurança que um doente com hipertiroidismo e TRAb positivo tem doença de Graves.

Anti-Phospholipase A2 Receptor Antibodies in the Diagnosis of Idiopathic Membranous Nephropathy

Circulating anti-phospholipase A2 receptor antibodies (anti-PLA2R) have been described in 70% to 80% of the patients with idiopathic membranous nephropathy (iMN), but not in patients with secondary membranous nephropathy or other glomerular diseases. The goal of this study was to evaluate the sensitivity and specificity of the assay for anti-PLA2R in the diagnosis of iMN. Anti-PLA2R IgG, Elisa and immunofluorescence tests were used to detect circulating anti-PLA2R. These tests were applied in 53 patients who had a kidney biopsy. Of these, 38 had histological diagnosis of membranous nephropathy (MN) and the remaining had other glomerular diseases. The MN was classified as idiopathic in 33 patients after clinical exclusion of secondary causes. Anti-PLA2R were positive in 57.6% of the patients with iMN. All patients with secondary membranous nephropathy or other glomerular diseases did not show circulating anti-PLA2R. The sensitivity was 57.6% (CI 39.2-74.5) and specificity 100% (CI 47.8-100), AUC 0.788; p < 0.0001 for the detection of iMN. 71.4% of the iMN patients that tested negative for anti-PLA2R were in partial or complete remission. The detection of anti-PLA2R in the studied population had a specificity of 100% for the iMN diagnosis. Prior treatments seem to make the test negative and contribute to a lower sensitivity.

Benefits of Selective Vitamin D Receptor Activators in Kidney Transplanted Patients

Severe chronic kidney disease may lead to disturbances, such as hyperphosphatemia, increased secretion of fibroblast growth factor -23 (FGF -23) and vitamin D deficiency. These may increase plasmatic levels of parathyroid hormone, and decrease plasmatic levels of calcium. Altogether, these may contribute to the development of secondary hyperparathyroidism, and to abnormalities in mineral metabolism. Kidney transplantation is the best option to improve longevity and quality of life in end -stage chronic kidney disease patients. Vitamin D deficiency has been associated with cardiovascular disease, which is the leading cause of death in chronic kidney disease. Therefore, diagnosing this deficiency may be pivotal for minimizing mortality in chronic kidney disease, because pharmacological treatments for this deficiency may be prescribed. Calcitriol is indicated for the treatment of vitamin D deficiency, both in chronic kidney disease and in kidney transplanted patients. However, calcitriol may increase the plasmatic levels of calcium and phosphorous, which can lead to vascular calcifications, that have been associated with cardiovascular mortality. Selective vitamin D receptor activators are indicated for the treatment of vitamin D deficiency in chronic kidney disease. These have the advantage of being associated with lower increases of plasmatic levels of calcium and phosphorous. These drugs also seem to have additional effects that may minimise patient morbidity and mortality, especially due to potentially reducing cardiovascular events. Unfortunately, there are few studies about the use of these drugs in kidney transplanted patients. Here we present a review about the physiology of vitamin D, the consequences of its deficiency in chronic kidney disease and in kidney transplanted patients, and about the diagnosis and treatment of this deficiency. Finally, we discuss the new line of research about the efficacy and safety of selective vitamin D receptor activators in kidney transplanted patients.

Hipotiroidismo Associado a Anticorpos Anti-Receptor da Hormona TSH com Ação Bloqueadora Determinada In Vitro

Thyroid-stimulating hormone-receptor autoantibodies normally causes hyperthyroidism. However, they might have blocking activity causing hypothyroidism. A 11-year-old girl followed due to type 1 diabetes mellitus, celiac disease and euthyroid lymphocytic thyroiditis at diagnosis. Two years after the initial evaluation, thyroid-stimulating hormone was suppressed with normal free T4; nine months later, a biochemical evolution to hypothyroidism with thyroid-stimulating hormone-receptor autoantibodies elevation was seen; the patient remained always asymptomatic. Chinese hamster ovary cells were transfected with the recombinant human thyroid-stimulating hormone -receptor, and then exposed to the patient's serum; it was estimated a 'moderate' blocking activity of these thyroid-stimulating hormone-receptor autoantibodies, and concomitantly excluded stimulating action. In this case, the acknowledgment of the blocking activity of the serum thyroid-stimulating hormone-receptor autoantibodies, supported the hypothesis of a multifactorial aetiology of the hypothyroidism, which in the absence of the in vitro tests, we would consider only as a consequence of the destructive process associated to lymphocytic thyroiditis.

Novel FGFR1 Mutations in Kallmann Syndrome and Normosmic Idiopathic Hypogonadotropic Hypogonadism: Evidence for the Involvement of an Alternatively Spliced Isoform

OBJECTIVE: To determine the prevalence of fibroblast growth factor receptor 1 (FGFR1) mutations and their predicted functional consequences in patients with idiopathic hypogonadotropic hypogonadism (IHH). DESIGN: Cross-sectional study. SETTING: Multicentric. PATIENT(S): Fifty unrelated patients with IHH (21 with Kallmann syndrome and 29 with normosmic IHH). INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Patients were screened for mutations in FGFR1. The functional consequences of mutations were predicted by in silico structural and conservation analysis. RESULT(S): Heterozygous FGFR1 mutations were identified in six (12%) kindreds. These consisted of frameshift mutations (p.Pro33-Alafs*17 and p.Tyr654*) and missense mutations in the signal peptide (p.Trp4Cys), in the D1 extracellular domain (p.Ser96Cys) and in the cytoplasmic tyrosine kinase domain (p.Met719Val). A missense mutation was identified in the alternatively spliced exon 8A (p.Ala353Thr) that exclusively affects the D3 extracellular domain of FGFR1 isoform IIIb. Structure-based and sequence-based prediction methods and the absence of these variants in 200 normal controls were all consistent with a critical role for the mutations in the activity of the receptor. Oligogenic inheritance (FGFR1/CHD7/PROKR2) was found in one patient. CONCLUSION(S): Two FGFR1 isoforms, IIIb and IIIc, result from alternative splicing of exons 8A and 8B, respectively. Loss-of-function of isoform IIIc is a cause of IHH, whereas isoform IIIb is thought to be redundant. Ours is the first report of normosmic IHH associated with a mutation in the alternatively spliced exon 8A and suggests that this disorder can be caused by defects in either of the two alternatively spliced FGFR1 isoforms.

Clinical and Genetic Characterization of Portuguese Patients with Pseudohypoparathyroidism Type Ib

Patients with pseudohypoparathyroidism type Ib (PHP-Ib) present hypocalcemia and hyperphosphatemia, as a consequence of a resistance to PTH action, through its G-protein-coupled receptor, in the renal tubules. This resistance results from tissue-specific silencing of the G-protein alpha-subunit (G(s)α), due to imprinting disruption of its encoding locus--GNAS. In familial PHP-Ib, maternally inherited deletions at the STX16 gene are associated to a regional GNAS methylation defect. In sporadic PHP-Ib, broad methylation changes at GNAS arise from unknown genetic causes. In this study, we describe the clinical presentation of PHP-Ib in four Portuguese patients (two of whom were siblings), and provide further insight for the management of patients with this disease. The diagnosis of PHP-Ib was made after detection of GNAS imprinting defects in each of the cases. In the siblings, a regional GNAS methylation change resulted from a known 3.0 kb STX16 deletion. In the other two patients, the broad methylation defects at GNAS, which were absent in their relatives, resulted from genetic alterations that remain to be identified. We report the first clinical and genetic study of Portuguese patients with PHP-Ib. The genetic identification of a hereditary form of this rare disease allowed an early diagnosis, and may prevent hypocalcemia-related complications.