A 17q21.31 microdeletion encompassing the MAPT gene in a mentally impaired patient

About 15% of patients with a clinical phenotype of Angelman syndrome (AS) have an unknown etiology. We report a patient with features reminiscent of AS, including a pattern of characteristic facial anomalies as well as speech impairment, developmental delay and frequent laughter. In addition, the patient had features not commonly associated with AS such as heart malformations and scoliosis. She was negative in SNURF-SNRPN exon 1 methylation studies and the G-banded karyotype was normal. Array-based comparative genomic hybridization disclosed a deletion of maximally 1 Mb at 17q21.31. The deleted region contains the MAPT gene, implicated in late onset neurodegenerative disorders, and the STH and NP_056258.1 genes. Another gene, such as CRHR1, might also be included based on maximum possible size of the deletion. We suggest that microdeletions within the 17q21.31 segment should be considered as a possible cause of phenotypes resembling AS, particularly when easily controlled seizures and/or cardiac abnormalities are also present.

Impact of molecular mechanisms, including deletion size, on Prader-Willi syndrome phenotype: study of 75 patients

Prader-Willi syndrome (PWS) can result from a 15q11-q13 paternal deletion, maternal uniparental disomy (UPD), or imprinting mutations. We describe here the phenotypic variability detected in 51 patients with different types of deletions and 24 patients with UPD. Although no statistically significant differences could be demonstrated between the two main types of PWS deletion patients, it was observed that type I (BP1-BP3) patients acquired speech later than type II (BP2-BP3) patients. Comparing the clinical pictures of our patients with UPD with those with deletions, we found that UPD children presented with lower birth length and started walking earlier and deletion patients presented with a much higher incidence of seizures than UPD patients. In addition, the mean maternal age in the UPD group was higher than in the deletion group. No statistically significant differences could be demonstrated between the deletion and the UPD group with respect to any of the major features of PWS. In conclusion, our study did not detect significant phenotypic differences among type I and type II PWS deletion patients, but it did demonstrate that seizures were six times more common in patients with a deletion than in those with UPD.

Angelman syndrome associated with oculocutaneous albinism due to an intragenic deletion of the P gene

Angelman syndrome (AS) is a neurodevelopmental disorder characterized by mental retardation, speech impairment, ataxia, and happy disposition with frequent smiling. AS results from the loss of expression of a maternal imprinted gene, UBE3A, mapped within 15q11-q13 region, due to different mechanisms: maternal deletion, paternal UPD, imprinting center mutation, and UBE3A mutation. Deletion AS patients may exhibit hypopigmentation of skin, eye, and hair correlating with deletion of P gene localized in the distal part of Prader-Willi (PWS)/AS region. Our patient presented developmental delay, severe mental retardation, absence of speech, outbursts of laughter, microcephaly, ataxia, hyperactivity, seizures, white skin, no retinal pigmentation, and gold yellow hair. His parents were of African ancestry. The SNURF-SNRPN methylation analysis confirmed AS diagnosis and microsatellite studies disclosed deletion with breakpoints in BP2 and BP3. All of the 25 exons and flanking introns of the P gene of the patient, his father, and mother were investigated. The patient is hemizygous for the deleted exon 7 of the P gene derived from his father who is a carrier of the deleted allele. Our patient manifests OCA2 associated with AS due to the loss of the maternal chromosome 15 with the normal P allele, and the paternal deletion in the P gene. As various degrees of hypopigmentation are associated with PWS and AS patients, the study of the P gene in a hemizygous state could contribute to the understanding of its effect on human pigmentation during development and to disclose the presence of modifier pigmentation gene(s) in the PWS/AS region.

Prader-Willi syndrome: genetic tests and clinical findings

Here we describe the genetic studies performed in 53 patients with the suspected diagnosis of Prader-Willi syndrome (PWS). PWS is characterized by neonatal hypotonia, hypogonadism, delayed psychomotor development, hyperphagia, obesity, short stature, small hands and feet, learning disabilities, and obsessive-compulsive behavior. Through the methylation analysis of the SNRPN gene, microsatellite studies of loci mapped within and outside the PWS/AS region, and fluorescence in situ hybridization (FISH) study, we confirmed the diagnosis in 35 patients: 27 with a paternal deletion, and 8 with maternal uniparental disomy (UPD). The clinical comparisons between deleted and UPD patients indicated that there were no major phenotype differences, except for a lower birth length observed in the UPD children. Our sample was composed of more girls than boys; UPD patients were diagnosed earlier than the deleted cohort (2(10/12) s. 7(9/12) years); and, in the deleted group, the boys were diagnosed earlier than the girls (5(2/12) vs. 7(8/12) years, respectively).

Paternal UPD15: further genetic and clinical studies in four Angelman syndrome patients

Among 25 patients diagnosed with Angelman syndrome, we detected 21 with deletion and 4 with paternal uniparental disomy (UPD), 2 isodisomies originating by postzygotic error, and 1 MII nondisjunction event. The diagnosis was obtained by molecular techniques, including methylation pattern analysis of exon 1 of SNRPN and microsatellite analysis of loci within and outside the 15q11-q13 region. Most manifestations present in deletion patients are those previously reported. Comparing the clinical data from our and published UPD patients with those with deletions we observed the following: the age of diagnosis is higher in UPD group (average 7 3/12 years), microcephaly is more frequent among deletion patients, UPD children start walking earlier (average age 2 9/12 years), whereas in deletion patients the average is 4 (1/2) years, epilepsy started later in UPD patients (average 5 10/12 years) than in deletion patients (average 1 11/12 years), weight above the 75th centile is reported mainly in UPD patients, complete absence of speech is more common in the deleted (88.9%) than in the UPD patients because half of the children are able to say few words. Thus, besides the abnormalities already described, the UPD patients have somewhat better verbal development, a weight above the 75th centile, and OFC in the upper normal range.

Unusual clinical features in an Angelman syndrome patient with uniparental disomy due to a translocation 15q15q

We had previously described a patient with an overgrowth syndrome and the chromosome constitution 45,XY,t(15q15q) (Wajntal et al., DNA Cell Biol 1993: 12: 227-231). Clinical reassessment and the use of molecular studies, including methylation analysis with an SNRPN probe, microsatellite analyses of D15S11, GABRB3 and D15S113 loci, and fluorescence in situ hybridization (FISH) using the SNRPN and GABRB3 probes, are consistent with a diagnosis of Angelman syndrome (AS) due to paternal isodisomy. This is the fourth report case of a translocation 15q15q with paternal uniparental disomy (UPD). Our findings suggest that some patients with clinical features of AS have hyperphagia and obesity with overgrowth, and that these features should not rule out a diagnosis of AS.

Cyclosporine A-induced decrease in calbindin-D 28 kDa in rat kidney but not in cerebral cortex and cerebellum

Recently, we reported that in rat, cyclosporine A (CsA) markedly decreases the levels of calbindin-D (CABP-D) 28 kDa in kidney. CABP-D 28 kDa is a calcium-binding protein which is highly expressed in calcium-transporting tissues such as kidney or brain. In this study, we investigated whether, in addition to the kidney, CsA also has an effect on CABP-D 28 kDa in rat brain. Three groups of male Wistar rats received 15 mg/kg/day or 50 mg/kg/day of CsA orally for 12 days, whereas controls received vehicle solution for the same period. CABP-D 28-kDa protein and CsA were quantified in homogenates of kidney, cerebral cortex and cerebellum, and the localization of CABP-D 28 kDa was assessed in the different tissue sections by immunohistochemistry. In kidney, CABP-D 28 kDa was strongly and dose dependently decreased, and was located in tubular epithelial cells. In brain, CABP-D 28 kDa was not changed and was mainly located in pyramidal cells of the cortex and in cerebellum exclusively in Purkinje cells. High CsA concentrations were measured in kidney, more than 17-fold greater than those found in cortex. In cerebellum, CsA was below the limit of detection. These data suggest that at clinically relevant doses, CsA may not affect CABP-D 28-kDa levels in brain.

The cyclosporine A-induced decrease in rat renal calbindin-D28kDa protein as a consequence of a decrease in its mRNA

Cyclosporine A (CsA) is a potent immunosuppressant with the drawback of renal side-effects. We recently reported that relatively high doses of CsA markedly decreased the calcium-binding protein calbindin-D28kDa in kidneys of male Wistar rats, and showed that this decrease could be associated with some of the drug-induced adverse renal effects. To investigate the events leading to this decrease, the calbindin-D28kDa mRNA level in kidneys of rats treated with 15 or 50 mg/kg/day CsA for 12 days was analysed by reverse transcription followed by polymerase chain reaction. At both doses, a marked dose-dependent decrease in the calbindin-D28kDa mRNA level was found, one very similar to the decrease measured in the calbindin-D28kDa protein abundance. Thus, the CsA-mediated down-regulation of the renal calbindin-D28kDa protein is most likely the result of a decrease in the calbindin-D28kDa mRNA level.

[Image of pseudocapture caused by micro-dislodgment of the electrode in a VDD pacemaker]

The new AV sequential pacemakers have improved the suitability for the election of the best pacing mode for each patient. The complexity of the systems may mask some dysfunctions. In the presented case, a failure to capture due to micro-dislodgment, may have been missed in a simple pacemaker control, because of the combination of several factors: the presence of normal AV conduction at that moment, the concordance between the pacemaker stimulus and the conducted QRS complex and the similar morphology of the conducted and paced QRS complex.

Decrease in kidney calbindin-D 28kDa as a possible mechanism mediating cyclosporine A- and FK-506-induced calciuria and tubular mineralization

The use of the immunosuppressant cyclosporine A (CsA) is limited by its adverse renal effects. Most recently, we reported that the drug markedly decreases the levels of the calcium-binding protein calbindin-D 28kDa in kidneys of male Wistar rats. In the present study, the potential relationship between drug-induced nephrotoxicity and the decrease in kidney calbindin-D 28kDa was investigated. Four groups of male Wistar rats were treated for 10 or 31 days with either the immunosuppressant CsA (50 mg/kg/day), FK-506 (5 mg/kg/day), rapamycin (5 mg/kg/day) or with the nonimmunosuppressive cyclosporine derivative 3'keto-[Bmt1]-[Val2]-CsA (SDZ PSC-833) (50 mg/kg/day), and the effects on calcium homeostasis, kidney histology and renal calbindin-D 28kDa were examined. Similar effects were found with CsA and FK-506; both drugs strongly reduced kidney calbindin-D 28kDa protein levels, increased urine calcium excretion, caused intratubular calcification, and induced basophilic tubules. In contrast, rapamycin and SDZ PSC-833 caused no decrease in renal calbindin-D 28kDa levels, no noticeable alterations in calcium metabolism, and no renal calcification. The results provide evidence for a link between decreased renal calbindin, increased calcium urine excretion, and intratubular kidney calcification. The present data show no correlation between the decrease in renal calbindin and the induction of basophilic tubules; however, it needs to be investigated if these apparently independent kidney effects may have a common origin upstream of calbindin expression.

Protein variability in male and female Wistar rat liver proteins

In the emerging field of mechanistic toxicology, growing attention is being paid to the interpretation of sex-related toxic responses. The Wistar rat outbred stock is a frequently used rodent for toxicity testing. Outbred strains, which display a relatively high degree of genetic variability between the individual animals are often used in risk assessment, as they are considered to best approximate the variability present in a human population. In this study two-dimensional (2-D) protein gel electrophoresis was applied to investigate the liver protein patterns of male and female Wistar rats and to search for (i) sex-related and (ii) interindividual qualitative and quantitative differences in protein expression. Among the sexes, six proteins were detected that were shown to be exclusively present in male rats and one that was present only in females. A male-specific protein was tentatively assigned to alpha 2u globulin. Seven protein spots showed statistically significant abundance changes (p < 0.001) between males and females, one was tentatively assigned to heme oxygenase 1 and another to the 23 kDa morphin-binding protein. Four sets of protein spots were detected that showed positional shifts in the individual patterns and are likely to represent polymorphic proteins inherent in the Wistar rat. These results form a valuable basis for future investigations of drug-induced changes in the male and female Wistar rat liver pattern.

Comparable seropositivity for ascariasis and toxocariasis in tropical slum children

The seropositivities for infection by Ascaris lumbricoides and Toxocara canis were determined in children (1-15 years old) of a slum area of Caracas, Venezuela, and the levels that indicate the presence of active infection were defined. In children aged from 1 to 3 years, approximately 10% were positive for either parasite, and this figure increased to about 30% in 4- to 6-year-olds. For toxocariasis, the percentage of positivity remained at this level up to the age of 15 years. Whilst the positivity in children 10-15 years of age was comparable for Ascaris and Toxocara, a peak of positivity (50%) was found for Ascaris at 7-9 years of age. These results indicate that for these urban slum children, infection by Toxocara is essentially as common as that by Ascaris and, thus, that toxocariasis represents a potential public health problem in the tropical environment that is largely overlooked.

Modification of the methodology of stool culture for Salmonella detection

A total of 4,284 H2S-positive colonies isolated on salmonella-shigella agar and 4,350 isolated on Hektoen agar were flooded with 5 microliters of a reagent (MUCAP test; Biolife Italiana S.r.l., Milan, Italy) and observed after 3 to 5 min for the development of fluorescence produced in the presence of the C8 esterase enzyme. All of the 794 colonies isolated on salmonella-shigella agar and the 752 isolated on Hektoen agar and identified as positive for Salmonella spp. with conventional biochemical tests were found positive with the MUCAP test (the sensitivity was 100% and the negative predictive value was 100% for both media). Moreover, only six isolates identified by conventional biochemical tests as Proteus vulgaris were MUCAP test positive (the specificity was 99.8% and the positive predictive value was 99.2% for both media). On the basis of these results, we propose the use of the MUCAP test as a method for the screening of H2S-positive colonies and only subculturing on Kliger agar of those colonies which are MUCAP test positive. The MUCAP test is a rapid method for the presumptive detection of Salmonella spp. and reduces the work and material involved in testing.

Presumptive identification of Salmonella enterica using two rapid tests

Two rapid test for early detection of Salmonella enterica, the cytochrome oxidase test and a fluorescence test, were evaluated in 1,200 colonies which had been isolated from human feces and cultured on MacConkey and Salmonella-Shigella media. Using the fluorescence test there were no false negative results (sensitivity 100%) and of 205 positive cases 62 did not correspond biochemically to salmonella (specificity 94.1%); 44 of these 62 were positive in the cytochrome oxidase test, raising the specificity to 98.2%. In conclusion, the combination of the two tests could be very useful due to the ease of performance, low cost and excellent results obtained.