Visual associative learning to detect early episodic memory deficits and distinguish Alzheimer's disease from other types of dementia

OBJECTIVE

We investigated how well a visual associative learning task discriminates Alzheimer's disease (AD) dementia from other types of dementia and how it relates to AD pathology.

METHODS

3,599 patients (63.9 ± 8.9 years old, 41% female) from the Amsterdam Dementia Cohort completed two sets of the Visual Association Test (VAT) in a single test session and underwent magnetic resonance imaging. We performed receiver operating curve analysis to investigate the VAT's discriminatory ability between AD dementia and other diagnoses and compared it to that of other episodic memory tests. We tested associations between VAT performance and medial temporal lobe atrophy (MTA), and amyloid status (n = 2,769, 77%).

RESULTS

Patients with AD dementia performed worse on the VAT than all other patients. The VAT discriminated well between AD and other types of dementia (area under the curve range 0.70-0.86), better than other episodic memory tests. Six-hundred forty patients (17.8%) learned all associations on VAT-A, but not on VAT-B, and they were more likely to have higher MTA scores (odds ratios range 1.63 (MTA 0.5) through 5.13 for MTA ≥ 3, all p < .001) and to be amyloid positive (odds ratio = 3.38, 95%CI = [2.71, 4.22], p < .001) than patients who learned all associations on both sets.

CONCLUSIONS

Performance on the VAT, especially on a second set administered immediately after the first, discriminates AD from other types of dementia and is associated with MTA and amyloid positivity. The VAT might be a useful, simple tool to assess early episodic memory deficits in the presence of AD pathology.

Estuarine dissolved speciation and partitioning of trace metals: a novel approach to study biogeochemical processes

Estuaries are complex systems involving numerous biogeochemical gradients and processes that influence the behavior of trace metals. Lead (Pb), cadmium (Cd), and copper (Cu) speciation and partitioning were studied in the Gironde Estuary (SW France), using a multi-method approach in which data from innovative sensors and laboratory-based techniques were combined. For the first time in this system, the so-called dynamic fractions of the target metals (dissolved forms that are potentially bioavailable) were recorded on-board through voltammetry using unique antifouling gel-integrated microelectrode arrays (GIME) incorporated in a submersible sensing probe (TracMetal). Trace metals in the operationally defined dissolved <0.2 μm and <0.02 μm fractions, as well as complexed with suspended particles (collected after centrifugation) were quantified through sampling/laboratory-based techniques. High spatial resolution trace metal concentrations were monitored along the salinity gradient (S = 0.10 to S = 34.0) together with master bio-physicochemical parameters providing robust cruise-specific information on how well-known abiotic and biotic processes control the Gironde estuarine trace element partitioning, (i.e. conservative behavior, addition/removal). Combining conventional methods with GIME measurements showed: (i) the dominance of Cd dynamic species in the intra-estuarine total dissolved fraction (up to 90%), (ii) the importance of small colloids as trace metal carrier phases, desorbing and complexing dynamic fractions of Pb and Cu, and (iii) the potential influence of photo-redox processes remobilizing Pb under their dynamic forms (up to 80%). Data also suggest trace metal release/sorption by phytoplankton with an increase of dissolved Cu concentrations in the riverine branch, as well as Cu and Cd particulate concentrations showing higher levels towards productive coastal waters. This complete approach allowed to monitor key estuarine biogeochemical processes and highlighted the valuable use of the TracMetal to record subtle variations of potentially bioavailable dissolved metal fractions.

[An International Urogynecological Association (IUGA)/International Continence Society (ICS) joint report on the terminology for the conservative and non-pharmacological management of female pelvic floor dysfunction]

INTRODUCTION

There has been an increasing need for the terminology for the conservative management of female pelvic floor dysfunction to be collated in a clinically-based consensus report.

METHODS

This report combines the input of members and elected nominees of the Standardization and Terminology Committees of two International Organizations, the International Urogynecological Association (IUGA) and the International Continence Society (ICS), assisted at intervals by many external referees. An extensive process of nine rounds of internal and external review was developed to exhaustively examine each definition, with decision-making by collective opinion (consensus). Before opening up for comments on the webpages of ICS and IUGA, five experts from physiotherapy, neurology, urology, urogynecology and nursing were invited to comment on the paper.

RESULTS

A terminology report for the conservative management of female pelvic floor dysfunction, encompassing over 200 separate definitions, has been developed. It is clinically-based with the most common symptoms, signs, assessments, diagnoses and treatments defined. Clarity and user-friendliness have been key aims to make it interpretable by practitioners and trainees in all the different specialty groups involved in female pelvic floor dysfunction. Ongoing review is not only anticipated but will be required to keep the document updated and as widely acceptable as possible.

CONCLUSION

A consensus-based terminology report for the conservative management of female pelvic floor dysfunction has been produced aimed at being a significant aid to clinical practice and a stimulus for research.

Genotype Assignment of Haemophilia A by Use of Intragenic and Extragenic Restriction Fragment Length Polymorphisms

We performed DNA analysis in 20 families with haemophilia A in order to evaluate its usefulness for carrier detection and prenatal diagnosis.

The polymorphic Bell site within intron 18 of the factor VIII gene and the extragenic TaqI and Bglll polymorphic sites which are detected by the random DNA probes designated St 14 and DX13, respectively, were investigated for.

Two events of recombination were found between the St 14 and the haemophilia A locus in 51 informative meioses. In one of these recombinant meioses crossing over had also occurred between the DX13 and the haemophilia A locus. No further crossovers between the DX13 and the haemophilia A locus were found in 20 informative meioses.

Segregation analysis of the polymorphic markers and the deleterious mutation within the families allowed a diagnosis at the gene level for 52 out of 57 potential carriers. The new method considerably decreased the uncertainty about carriership for seventeen of the nineteen women with a probability of carriership between 5% and 95% based on pedigree analysis and factor VIII assays.

In seven cases chromosome and DNA analysis of a chorionic villus biopsy was carried out. Three of the fetuses were female, four were male. Three of the male fetuses had inherited the normal maternal X-chromosome and were, therefore, not affected. For another male fetus no diagnosis at the gene level was possible since the mother was homozygous for all the known restriction fragment length polymorphisms within or closely linked with the haemophilia A locus.

Two Genes Homologous with Human Protein S cDNA Are Located on Chromosome 3

A cDNA coding for the carboxy-terminal region of human protein S and containing a complete 3’-untranslated region, was isolated by a combination of antibody screening of a λgt11 human liver cDNA expression library and in situ hybridization of a pUC9 human liver cDNA library.

Hybridization analysis of human total DNA with radiolabelled non-overlapping cDNA restriction fragments revealed the existence of two genes per haploid genome homologous with the protein S cDNA. Both genes were mapped to chromosome 3 using human-rodent cell hybrids. Neither of the genes showed polymorphism for sixteen different enzymes upon hybridization with the protein S cDNA.

Quantitative agreement between [(15)O]H2O PET and model free QUASAR MRI-derived cerebral blood flow and arterial blood volume

The purpose of this study was to assess whether there was an agreement between quantitative cerebral blood flow (CBF) and arterial cerebral blood volume (CBVA) measurements by [(15)O]H2O positron emission tomography (PET) and model-free QUASAR MRI. Twelve healthy subjects were scanned within a week in separate MRI and PET imaging sessions, after which quantitative and qualitative agreement between both modalities was assessed for gray matter, white matter and whole brain region of interests (ROI). The correlation between CBF measurements obtained with both modalities was moderate to high (r(2): 0.28-0.60, P < 0.05), although QUASAR significantly underestimated CBF by 30% (P < 0.001). CBVA was moderately correlated (r(2): 0.28-0.43, P < 0.05), with QUASAR yielding values that were only 27% of the [(15)O]H2O-derived values (P < 0.001). Group-wise voxel statistics identified minor areas with significant contrast differences between [(15)O]H2O PET and QUASAR MRI, indicating similar qualitative CBVA and CBF information by both modalities. In conclusion, the results of this study demonstrate that QUASAR MRI and [(15)O]H2O PET provide similar CBF and CBVA information, but with systematic quantitative discrepancies.

Photodynamic optical sensor for buffer capacity and pH based on hydrogel-incorporated spiropyran

The kinetics of a light activated proton extraction correlates with the buffer capacity of a sample at a given pH.

[Evaluation of the electromyography activity of pelvic floor muscle during postural exercises using the Wii Fit Plus©. Analysis and perspectives in rehabilitation]

INTRODUCTION

The aim of this work was to evaluate the effect of postural awareness by using the Wii Fit Plus© on the quality of the baseline (automatic) activity of the pelvic floor muscles (PFM) measured by intravaginal surface electromyography (sEMG).

METHODS

Four healthy continent female subjects, all able to perform a voluntary contraction, undertook 2 sets of 3 various exercises offered by the software Wii Fit Plus© using the Wii balance board© (WBB): one set without any visual control and the second set with postural control and sEMG visual feedback. Simultaneously, we recorded the sEMG activity of the PFM.

RESULTS

Mean baseline activity of PFM in standing position at start was 2.87 mV, at submaximal voluntary contraction the sEMG activity raised at a mean of 14.43 mV (7.87-21.89). In the first set of exercises on the WBB without any visual feedback, the automatic activity of the PFM increased from 2.87 mV to 8.75 mV (7.96-9.59). In the second set, with visual postural and sEMG control, mean baseline sEMG activity even raised at 11.39 mV (10.17-11.58).

CONCLUSION

Among women able of a voluntary contraction of PFM, visualisation of posture with the help of the WBB and of sEMG activity of the PFM during static and dynamic Wii Fit Plus© activities, may improve the automatic activation of the PFMs.

LEVEL OF EVIDENCE

4.

CD226 (DNAM-1) is associated with susceptibility to juvenile idiopathic arthritis

OBJECTIVES

Juvenile idiopathic arthritis (JIA) is considered a complex genetic autoimmune disease. We investigated the association of genetic variants previously implicated in JIA, autoimmunity and/or immunoregulation, with susceptibility to JIA.

METHODS

A genetic association study was performed in 639 JIA patients and 1613 healthy controls of northwest European descent. Ninety-three single nucleotide polymorphisms (SNP) were genotyped in a candidate gene approach. Results of the entire JIA patient group (all subtypes) were compared with results obtained, alternatively, with a clinically homogeneous patient group including only oligoarticular and rheumatoid factor (RF) negative polyarticular JIA patients (n=493). Meta-analyses were performed for all SNPs that have been typed in other Caucasian JIA cohorts before.

RESULTS

SNPs in or near PTPN22, VTCN1, the IL2-IL21 region, ANKRD55 and TNFA were confirmed to be associated with JIA (p<0.05), strengthening the evidence for involvement of these genes in JIA. In the majority of these replicated SNPs, effect sizes were larger when analysing a homogeneous patient cohort than when analysing all subtypes. We identified two novel associations with oligoarticular and RF-negative polyarticular JIA: CD226 rs763361 (OR 1.30, 95% CI 1.12 to 1.51, p=0.0006) and CD28 rs1980422 (OR 1.29, 95% CI 1.07 to 1.55, p=0.008). Meta-analyses including reported studies confirmed the association of both SNPs with susceptibility to JIA (OR 1.16, p=0.001 and OR 1.18, p=0.001, for rs763361 and rs1980422, respectively).

CONCLUSIONS

The CD226 gene has been identified as novel association with JIA, and a SNP near CD28 as a suggestive association. Both genes are probable candidate risk factors, since they are involved in costimulation of T cells.

Accuracy and precision of pseudo-continuous arterial spin labeling perfusion during baseline and hypercapnia: a head-to-head comparison with ¹⁵O H₂O positron emission tomography

Measurements of the cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) provide useful information about cerebrovascular condition and regional metabolism. Pseudo-continuous arterial spin labeling (pCASL) is a promising non-invasive MRI technique to quantitatively measure the CBF, whereas additional hypercapnic pCASL measurements are currently showing great promise to quantitatively assess the CVR. However, the introduction of pCASL at a larger scale awaits further evaluation of the exact accuracy and precision compared to the gold standard. (15)O H₂O positron emission tomography (PET) is currently regarded as the most accurate and precise method to quantitatively measure both CBF and CVR, though it is one of the more invasive methods as well. In this study we therefore assessed the accuracy and precision of quantitative pCASL-based CBF and CVR measurements by performing a head-to-head comparison with (15)O H₂O PET, based on quantitative CBF measurements during baseline and hypercapnia. We demonstrate that pCASL CBF imaging is accurate during both baseline and hypercapnia with respect to (15)O H₂O PET with a comparable precision. These results pave the way for quantitative usage of pCASL MRI in both clinical and research settings.

Genetic variation in VTCN1 (B7-H4) is associated with course of disease in juvenile idiopathic arthritis

OBJECTIVE

The course of disease in juvenile idiopathic arthritis (JIA) is unpredictable with episodes of activity and remission. In order to identify predictive factors, 93 SNPs, JIA subtype, age at onset and ANA status were studied in relation to disease course.

METHODS

Genetic and clinical parameters were analysed in a cohort of 272 Caucasian patients with persistent oligoarthritis (n=129), extended oligoarthritis (n=57) and rheumatoid factor negative polyarthritis (n=86). Categories of disease course (remitting (n=65), intermediate (n=96) and unremitting (n=111)) were designed based on the cumulative time spent in active disease in the first 2 years.

RESULTS

Univariate analysis revealed association of the course of disease with JIA subtype (p=5.7*10(-5)) and three SNPs; VTCN1 rs10 923 223 (p=4.4*10(-5)), VTCN1 rs12 046 117 (p=0.017) and CDK6 rs42 041 (p=0.038). In a subsequent multivariate ordinal logistic regression analysis, VTCN1 rs10 923 223 (OR 0.41, 95%-CI 0.26 to 0.63) and JIA subtype (OR 3.8, 95%-CI 2.0 to 7.2; OR 2.5, 95%-CI 1.4 to 4.2, for extended oligoarthritis and RF-negative polyarthritis vs persistent oligoarthritis, respectively) were the strongest independent factors for course of disease.

CONCLUSIONS

This study provides evidence that VTCN1, encoding B7-H4, is associated with course of disease in selected subtypes of JIA. VTCN1 might be useful in predicting the course of disease.

After the introduction into the national newborn screening program: who is receiving genetic counseling for hemoglobinopathies in the Netherlands?

OBJECTIVE

Universal newborn screening for hemoglobinopathies started in The Netherlands in 2007. Herewith severe conditions, such as sickle cell disease, β-thalassemia major and hemoglobin H disease are putatively identified. Additionally, at least 1,800 carriers of hemoglobin variants associated with severe conditions in homozygote or compound heterozygote forms are identified yearly. Thus far, approximately 60 patients and 800 healthy sickle cell (HbS) carriers are reported each year among 180,000 newborns. Results are sent to the general practitioner with the recommendation to inform and diagnose both parents of the healthy carriers to exclude genetic risk, while patients and their parents are referred directly to a pediatrician. This study was performed to determine how often parents of identified carriers and affected newborns are seen in genetic centers for counseling.

METHODS

In this retrospective study, we collected anonymized data from 7 of the 8 Dutch clinical genetic centers from January 1, 2007, until December 31, 2010.

RESULTS

After an initial general increase in total counseling intakes, a decline was noticed in the third year, while the requests for prenatal diagnoses remained relatively stable. In 2007 and 2013, genetic counselors were asked for self-reported knowledge. They found hemoglobinopathy counseling complex, but by 2013, they indicated they had acquired sufficient knowledge on most hemoglobinopathy aspects.

CONCLUSION

We could not observe a significant increase in genetic counseling for hemoglobinopathy after its introduction into newborn screening. Although 120 HbS carriers and 60 patients are expected to be born from couples at risk annually, only 33 at risk couples out of 540 families of diagnosed newborns received optimal care and information at a genetics center in 4 years.

Basic haemoglobinopathy diagnostics in Dutch laboratories; providing an informative test result

INTRODUCTION

After a first survey in 2001, the Dutch Association of Hematological Laboratory Research (VHL) advised its members to adopt a basic protocol for haemoglobinopathy carrier detection and to provide genetic information with all positive results to allow health-care professionals to inform carriers about potential genetic risks. This article reports on the compliance with these recommendations and their consequences.

METHODS

Clinical chemists of all 106 Dutch laboratories were invited to answer a survey on patient population, diagnostic techniques used, (self-reported) knowledge, use and effect of the additional information.

RESULTS

The average increase in diagnostic output was over 60% and the recommended basic protocol was applied by 65% of the laboratories. Over 84% of the laboratories reported to be aware of the additional recommendations and 77% to be using them. Most laboratories with limited diagnostic requests were still sending their cases to other laboratories and included the genetic information received from these laboratories in their diagnostic reports. The effect of information on subsequent 'family analysis' was estimated to be between 26 and 50%.

CONCLUSIONS

The present study shows an increase in diagnostic potential for haemoglobinopathy over the last decade, especially in the larger cities. Low 'family testing' rates were mostly found in areas with lower carrier prevalence or associated with local reluctance to pass the information to carriers. In spite of a dramatic improvement, too many carriers are still not informed because of lack of awareness among health-care providers and more education is needed.

Nitrite-selective microelectrodes

The development of nitrite-selective liquid membrane microelectrodes based on a synthetic charged ionophore is described. The addition of potassium tetrakis(4-chlorophenyl)borate and poly(vinyl chloride) to the membrane phase is essential to lower the ohmic resistance and to prolong the lifetime of the microelectrodes. The detection limits for sodium nitrite solutions without and with an ion background of 0.1M chloride are 10(-5.1) and 10(-4.2)M, respectively. The comparison with macroelectrodes shows that the miniaturization reduces, to some extent, the selectivity and the slopes of the EMF response functions.

General description of the simultaneous response of potentiometric ionophore-based sensors to ions of different charge

The response of ion-selective membrane electrodes is usually still described with the semiempirical Nicolskii-Eisenman equation although it cannot correctly reproduce experimental data if ions of different charges are involved. The recently published self-consistent model that was derived for two ions of any charges is now extended to any number of ions of any charge. One single explicit equation is here given for the first time for any number of monovalent, divalent, and trivalent ions. Deviations relative to the Nicolskii-Eisenman equation are shown to be especially high at low interferences and bias calibrations if done in a mixed solution of a target sample as well as multivariate calibrations with sensor arrays.

No evidence for JAK2(V617F) mutation in monoclonal B cells in 2 patients with polycythaemia vera and concurrent monoclonal B cell disorder

Occurrence of Philadelphia chromosome-negative myeloproliferative neoplasms (Ph(-) MPN) and lymphoproliferative disorders, like B cell chronic lymphocytic leukaemia (B-CLL), in the same patient is rare. JAK2(V617F) mutation was recently introduced as a powerful diagnostic tool for Ph(-) MPN. JAK2(V617F) mutation is not present in B-CLL. In 4 previously reported patients with JAK2(V617F)-positive Ph(-) MPN and B-CLL there was no definitive proof of JAK2(V617F) mutation in B-CLL cells, although this was suggested in 1 patient. We present 2 patients with JAK2(V617F)-positive polycythaemia vera who subsequently developed a monoclonal B cell disorder. The granulocytes were separated from the mononuclear cells by centrifugation on density gradient. Using an ARIA-SORP sorter, the CD20+/CD5+ B cells were separated from the CD20+/CD5- B cells, T cells, NK cells and monocytes. On each of the fractions JAK2(V617F) mutation was analysed by allele-specific competitive blocker-PCR. In both patients JAK2(V617F) mutation was present in granulocytes confirming the clinical diagnosis of polycythaemia vera. We did not detect the JAK2(V617F) mutation in the CD20+/CD5+ B cells but detected it in CD20+/CD5- B cells, T and NK cells, indicating a lymphoid subdifferentiation of the JAK2(V617F) MPN clonality. JAK2(V617F) MPN and monoclonal B cell disorder can coexist but there is no evidence that the proliferative behaviour of these B cells is mediated through the JAK2(V617F) mutation.

The determinants of periorbital skin ageing in participants of a melanoma case-control study in the U.K

BACKGROUND

Skin ageing is said to be caused by multiple factors. The relationship with sun exposure is of particular interest because the detrimental cutaneous effects of the sun may be a strong motivator to sun protection. We report a study of skin ageing in participants of an epidemiological study of melanoma.

OBJECTIVES

To determine the predictors of periorbital cutaneous ageing and whether it could be used as an objective marker of sun exposure.

METHODS

Photographs of the periorbital skin in 1341 participants were graded for wrinkles, degree of vascularity and blotchy pigmentation and the resultant data assessed in relation to reported sun exposure, sunscreen use, body mass index (BMI), smoking and the melanocortin 1 receptor (MC1R) gene status. Data were analysed using proportional odds regression.

RESULTS

Wrinkling was associated with age and heavy smoking. Use of higher sun-protection factor sunscreen was protective (P = 0·01). Age, male sex, MC1R variants ('r', P=0·01; 'R', P=0·02), higher reported daily sun exposure (P=0·02), increased BMI (P=0·01) and smoking (P=0·02) were risk factors for hypervascularity. Blotchy pigmentation was associated with age, male sex, higher education and higher weekday sun exposure (P=0·03). More frequent sunscreen use (P=0·02) and MC1R variants ('r', P=0·03; 'R', P=0·001) were protective.

CONCLUSIONS

Periorbital wrinkling is a poor biomarker of reported sun exposure. Vascularity is a better biomarker as is blotchy pigmentation, the latter in darker-skinned individuals. In summary, male sex, sun exposure, smoking, obesity and MC1R variants were associated with measures of cutaneous ageing. Sunscreen use showed some evidence of being protective.

X-chromosome duplications in males with mental retardation: pathogenic or benign variants?

Studies to identify copy number variants (CNVs) on the X-chromosome have revealed novel genes important in the causation of X-linked mental retardation (XLMR). Still, for many CNVs it is unclear whether they are associated with disease or are benign variants. We describe six different CNVs on the X-chromosome in five male patients with mental retardation that were identified by conventional karyotyping and single nucleotide polymorphism array analysis. One deletion and five duplications ranging in size from 325 kb to 12.5 Mb were observed. Five CNVs were maternally inherited and one occurred de novo. We discuss the involvement of potential candidate genes and focus on the complexity of X-chromosomal duplications in males inherited from healthy mothers with different X-inactivation patterns. Based on size and/or the presence of XLMR genes we were able to classify CNVs as pathogenic in two patients. However, it remains difficult to decide if the CNVs in the other three patients are pathogenic or benign.

TREX1 mutations are not associated with sporadic inclusion body myositis

BACKGROUND

Sporadic inclusion body myositis (sIBM) is the most frequent acquired myopathy above the age of fifty. The exact mechanism causing this disease is not known, but immune-mediated features are prominent and are probably to play a role in its pathogenesis. TREX1 gene mutations are associated with a large range of autoimmune diseases, such as systemic lupus erythematosus. We investigated whether mutations in the TREX1 gene were associated with sIBM.

METHODS

Fifty-four patients with sIBM were tested for TREX1 mutations by direct sequencing.

RESULTS

All 54 patients tested negative for pathogenic mutations in the TREX1 gene. One presumed non-pathogenic polymorphism was found in 42 out of 54 patients.

CONCLUSION

TREX1 mutations do not play a role in the pathogenesis of sIBM.

Becker muscular dystrophy patients with deletions around exon 51; a promising outlook for exon skipping therapy in Duchenne patients

Theoretically, 13% of patients with Duchenne muscular dystrophy may benefit from antisense-mediated skipping of exon 51 to restore the reading frame, which results in the production of a shortened dystrophin protein. We give a detailed description with longitudinal follow up of three patients with Becker muscular dystrophy with in-frame deletions in the DMD gene encompassing exon 51. Their internally deleted, but essentially functional, dystrophins are identical to those that are expected as end products in DMD patients treated with the exon 51 skipping therapy. The mild phenotype encourages further development of exon 51 skipping therapy.

Parental history of Alzheimer disease associated with lower plasma apolipoprotein E levels

BACKGROUND

Variation in APOE genotype is a determinant of Alzheimer disease (AD), but the risk associated with variation in plasma apoE levels has yet to be determined. Here, we studied offspring with and without a parental history of AD to identify the effect of plasma apoE levels at middle age on the risk of late-onset AD.

METHODS

Some 203 offspring from 92 families with a parental history of AD were compared with 197 offspring from 97 families without a parental history of AD. APOE genotypes and plasma apoE levels were assessed in all offspring. Difference in plasma apoE level between subjects with and without a parental history of AD was calculated using robust linear regression, both stratified and adjusted for APOE genotype.

RESULTS

Offspring with a parental history of AD were more likely to be an APOE epsilon4 allele carrier (46% vs 21%, p < 0.001) than offspring without such a parental history. Mean plasma apoE levels strongly decreased from epsilon2 to epsilon3epsilon3 to epsilon4 carriers (p < 0.001). Offspring with a parental history of AD had lower plasma apoE levels than subjects without such a history, both in analyses adjusted for APOE genotype (difference: -0.21 mg/dL, p = 0.02) and when using standardized Z scores, when stratified for APOE genotype (difference: -0.22, p = 0.009).

CONCLUSIONS

Our findings suggest that lower plasma apoE levels in middle age could be a risk factor for Alzheimer disease in old age, independent of APOE genotype.

Recurrence risk due to germ line mosaicism: Duchenne and Becker muscular dystrophy

The presence of multiple affected offspring from apparently non-carrier parents is caused by germ line mosaicism. Although germ line mosaicism has been reported for many diseases, figures for recurrence risks are known for only a few of them. In X-linked Duchenne and Becker muscular dystrophies (DMD/BMD), the recurrence risk for non-carrier females due to germ line mosaicism has been estimated to be between 14% and 20% (95% confidence interval 3-30) if the risk haplotype is transmitted. In this study, we have analyzed 318 DMD/BMD cases in which the detected mutation was de novo with the aim of obtaining a better estimate of the 'true' number of germ line mosaics and a more precise recurrence risk. This knowledge is essential for genetic counseling. Our data indicate a recurrence risk of 8.6% (4.8-12.2) if the risk haplotype is transmitted, but there is a remarkable difference between proximal (15.6%) (4.1-27.0) and distal (6.4%) (2.1-10.6) deletions. Overall, most mutations originated in the female. Deletions occur more often on the X chromosome of the maternal grandmother, whereas point mutations occur on the X chromosome of the maternal grandfather. In unhaplotyped de novo DMD/BMD families, the risk of recurrence of the mutation is 4.3%.

Emergency operation on the dissected ascending aorta of an adolescent with aortic coarctation

This case report describes the successful repair of an acute dissection of the ascending aorta in a 16-year-old girl. The dissection appeared to be related to the presence of an aortic coarctation. Furthermore, a bicuspid aortic valve was found. Echocardiography was helpful for quick pre-operative diagnosis. A computed tomography (CT) scan was used post-operatively to confirm these results. At the onset of extracorporeal circulation, active drainage was applied at the femoral vein by means of a routinely built-in shunt bypassing the venous reservoir. The practical implementation of this shunt is described in this report. One femoral artery and one femoral vein were cannulated, resulting in a blood flow index of 2.21.min(-l).m(-2) which proved to be sufficient for blood supply to both the lower and the upper parts of the body. Successful percutaneous dilatation of the coarctation was performed five months after the first operation.

Somatic APC mosaicism: an underestimated cause of polyposis coli

BACKGROUND

The patient with 10 or more adenomas in the colon poses a diagnostic challenge. Beside germline mutations in the APC and MUTYH genes, only four cases of mosaic APC mutations have been reported.

AIM

Given the relatively high frequency of de novo APC mutations in familial adenomatous polyposis (FAP), an investigation was carried out into whether the proportion of somatic mosaic APC mutations is currently underestimated.

METHODS

Between 1 January 1994 and 31 December 2005 germline mutation analysis was performed in 599 consecutive index patients with polyposis coli referred for diagnostic APC scanning using a combination of denaturing gradient gel electrophoresis (DGGE) and protein truncation test (PTT). Variants were analysed by direct sequencing with primers flanking those used for DGGE and PTT, and quantified using pyrosequencing.

RESULTS

Scrutinizing the molecular genetic results and family data of 242 index patients with pathogenic APC mutations led to the identification of 10 mosaic cases (4%). C>T transitions were observed in CGA sites in four of the 10 cases with somatic mosaicism, which is significantly more than 26 of the 232 non-mosaic cases (p = 0.02). Phenotypes of patients with somatic mosaicism ranged from an attenuated form of polyposis coli to florid polyposis with major extracolonic manifestations.

CONCLUSIONS

Mosaicism occurs in a significant number of APC mutations and it is estimated that one-fifth of the de novo cases of FAP are mosaic. Clinically, the severity of manifestations in offspring and the recurrence risk for siblings of apparently sporadic polyposis patients may be underestimated due to parental APC mosaicism.

Limb-girdle muscular dystrophy in the Netherlands: gene defect identified in half the families

Pheno- and genotype correlation is attempted in a Dutch cross-sectional study on limb- girdle muscular dystrophy. Sarcoglycans, caveolin-3, calpain-3, and dysferlin were analyzed on muscle tissue. Mutation analysis of the calpain-3, caveolin-3, and fukutin-related protein gene was executed in successive order for all samples. In 51% of all families a classifying diagnosis was made. Several new mutations in LGMD2A, B, and C patients have been found in this population.

Relationship between DHA status at birth and child problem behaviour at 7 years of age

Animal studies have demonstrated behavioural effects of long-chain polyunsaturated fatty acid (LC-PUFA) deficiencies and in humans, several psychiatric disorders have been linked to abnormal essential fatty acid metabolism. The aim of this study was to examine the relationship between LC-PUFA status at birth and the later development of problem behaviour. In a sample of 393 children, higher levels of docosahexaenoic acid (DHA) at birth were associated with lower levels of internalising problem behaviour at age 7 years. The association was markedly present in the infants fed with artificial formula (n=215, Beta=-0.32, P=0.000), but absent in the infants fed with human milk (n=170, Beta=0.11, P=0.325). The associations between arachidonic acid and internalising or externalising behaviour were neither large nor significant. The results suggest that perinatal DHA status may have long-term behavioural consequences. Therefore, we suggest to include measures of problem behaviour in future trials of LC-PUFA supplementation of mothers and/or infants.

A 6Mb deletion in band 2q22 due to a complex chromosome rearrangement associated with severe psychomotor retardation, microcephaly and distinctive dysmorphic facial features

High-resolution analyses of complex chromosome rearrangements (CCR) have demonstrated in individuals with abnormal phenotypes that not all seemingly balanced CCRs based on G-banding are completely balanced at breakpoint level. Here we report on an apparently balanced de novo CCR involving chromosomes 2, 3 and 5 present in a 6-month-old girl. She was referred for genetic evaluation because of severe psychomotor retardation, distinctive dysmorphic features and microcephaly. A 1Mb resolution array-CGH analysis of DNA from the patient revealed a deletion of about 6Mb for chromosome 2. FISH analysis showed that the deletion interval found in band 2q22 mapped at the translocation breakpoint, and that the ZFHX1B gene, which is known to be involved in the Mowat-Wilson syndrome, is located within the deletion interval. To our knowledge this is the first case of a complex chromosomal rearrangement associated with Mowat-Wilson syndrome. Our data illustrate the important role for high-resolution investigation of apparently balanced chromosome rearrangements in patients with unexplained psychomotor retardation and/or other clinical features, and should contribute to our understanding of the mechanisms involved in chromosome rearrangement.

Shoe adaptation after amputation of the II - V phalangeal bones of the foot

In The Netherlands, about 50% of all amputations of the lower limb are toes and forefoot amputations. Traumata of toes and mid-foot are rare. Preservation of the foot is the primary goal for treatment. Crush injuries of the foot may be associated with prolonged morbidity. This case study presents an insole solution for the solitary first phalangeal bone after amputation of the phalangeal bones II - V. The normal adaptation for forefoot amputations is stiffening of the sole of the shoe and a rocker bar to improve the toe off phase with load reduction of the forefoot. Because the patient had to do excessive stair climbing during work another solution was chosen. As a foot orthosis, a metal soleplate was made in order to have free movement during loading and toe-off during walking. The soleplate gives safety and provides self-adjusting properties after toe off. This enables the shoe technician to make a shoe without a rocker bar or an extra stiff insole. The 0.5 mm custom-made spring-steel plate is also used as a protective in industrial safety shoes. To improve shoe adaptation more research and case reports have to be published in order to inform doctors and shoe technicians about everyday solutions to partial foot amputations.

Disturbance of the fetal thyroid hormone state has long-term consequences for treatment of thyroidal and central congenital hypothyroidism

BACKGROUND

During T(4) supplementation of patients with thyroidal (primary) congenital hypothyroidism (CH) TSH concentrations are frequently elevated despite free T(4) (FT(4)) concentrations being well within the reference range. To examine the thyroid's regulatory system, we analyzed thyroid function determinants in children with congenital and acquired thyroid disorders and in controls.

METHODS

Retrospectively, plasma FT(4), TSH, and T(3) concentrations were analyzed in T(4)-supplemented children aged 0.5-20.0 yr with thyroidal CH, central (secondary or tertiary) CH, or autoimmune thyroid disease and in control children with type 1 diabetes mellitus.

RESULTS

When TSH was within the reference range (0.4-4.0 mU/liter), mean FT(4) in thyroidal CH [1.65 ng/dl; 95% confidence interval (CI), 1.62-1.67] was significantly higher than in autoimmune thyroid disease (1.15 ng/dl; 95% CI, 1.11-1.19) and diabetes (1.08 ng/dl; 95% CI, 1.06-1.10). In central CH, when TSH was less than or equal to 0.02 mU/liter, mean FT(4) was 1.27 ng/dl (95% CI, 1.24-1.29). When FT(4) was within the reference range (0.78-1.79 ng/dl), 43% of the TSH measurements in thyroidal CH were more than 4.0 mU/liter, compared with 18% in autoimmune thyroid disease and 0% in type 1 diabetes mellitus; in central CH, 95% of TSH measurements were less than 0.4 mU/liter.

CONCLUSIONS

In T(4)-supplemented patients with thyroidal CH, when TSH concentrations are established within the reference range, FT(4) concentrations tend to be elevated, and vice versa. Because this phenomenon could not be observed in acquired thyroidal hypothyroidism, we hypothesize that a pre- and/or perinatal hypothyroid state shifts the setpoint of the thyroid's regulatory system. In central CH, when FT(4) concentrations are established within the reference range, the pituitary secretes only minute amounts of TSH. For monitoring T(4) supplementation, reference ranges for FT(4) and TSH should be adapted to the etiology of hypothyroidism.

Array-CGH detection of micro rearrangements in mentally retarded individuals: clinical significance of imbalances present both in affected children and normal parents

BACKGROUND

The underlying causes of mental retardation remain unknown in about half the cases. Recent array-CGH studies demonstrated cryptic imbalances in about 25% of patients previously thought to be chromosomally normal.

OBJECTIVE AND METHODS

Array-CGH with approximately 3500 large insert clones spaced at approximately 1 Mb intervals was used to investigate DNA copy number changes in 81 mentally impaired individuals.

RESULTS

Imbalances never observed in control chromosomes were detected in 20 patients (25%): seven were de novo, nine were inherited, and four could not have their origin determined. Six other alterations detected by array were disregarded because they were shown by FISH either to hybridise to both homologues similarly in a presumptive deletion (one case) or to involve clones that hybridised to multiple sites (five cases). All de novo imbalances were assumed to be causally related to the abnormal phenotypes. Among the others, a causal relation between the rearrangements and an aberrant phenotype could be inferred in six cases, including two imbalances of the X chromosome, where the associated clinical features segregated as X linked recessive traits.

CONCLUSIONS

In all, 13 of 81 patients (16%) were found to have chromosomal imbalances probably related to their clinical features. The clinical significance of the seven remaining imbalances remains unclear. The limited ability to differentiate between inherited copy number variations which cause abnormal phenotypes and rare variants unrelated to clinical alterations currently constitutes a limitation in the use of CGH-microarray for guiding genetic counselling.

EAA/EMQN best practice guidelines for molecular diagnosis of y-chromosomal microdeletions. State of the art 2004

Microdeletions of the Y chromosome are the second most frequent genetic cause of spermatogenetic failure in infertile men after the Klinefelter syndrome. The molecular diagnosis of Y-chromosomal microdeletions is routinely performed in the workup of male infertility in men with azoospermia or severe oligozoospermia. Since 1999, the European Academy of Andrology (EAA) and the European Molecular Genetics Quality Network (EMQN) support the improvement of the quality of the diagnostic assays by publication of the laboratory guidelines for molecular diagnosis of Y-chromosomal microdeletions and by offering external quality assessment trials. The present revision of the 1999 laboratory guidelines summarizes the results of a 'Best Practice Meeting' held in Florence (Italy) in October 2003. The basic protocol for microdeletion screening suggested in the 1999 guidelines proved to be very accurate, sensitive and robust. In the light of the recent advance in the knowledge of the Y chromosome sequence and of the mechanism of microdeletion it was agreed that the basic 1999 protocol, based on two multiplex polymerase chain reactions each covering the three AZF regions, is still fully valid and appropriate for accurate diagnosis.

Risk factors for recurrent urinary tract infection in 4,332 Belgian schoolchildren aged between 10 and 14 years

To analyse the risk factors for recurrent urinary tract infection (UTI) and the possible influence of potty-training, a questionnaire with 41 questions was completed by 4,332 parents of children completing the last 2 years of normal primary school. Statistical analysis was done with the Chi-squared test and Yates correction. Three groups of children emerged: one without any history of UTI ( n=3818), a group with one actual or former UTI ( n=382) and a group with recurrent UTI ( n=132). Mean age was 11.5+/-0.56 years. A strong correlation between daytime and/or night-time wetting, voiding frequency of more than 10 times a day and nocturia and recurrent UTI was found. No correlation between these factors and a single UTI could be demonstrated. In the 343 bed-wetting children, equal infections for boys and girls were found. Potty-training started significantly earlier in children without UTI. Parents of children with recurrent UTIs insisted more when the first attempt to void was unsuccessful: in the group without UTI, most parents just postponed and had the child try later again. In the group with recurrent UTI, more parents asked the child to strain, made special noises or turned on a tap.

CONCLUSION

Daytime with/without night-time wetting, more than 10 voidings a day and nocturia are indicators of recurrent urinary tract infections. If they are simultaneously present, the relative risk for recurrent urinary tract infections is 60%. Consequently, paediatricians should take urinary symptoms very seriously into account, and as incontinence is still a hidden condition, question the child on this topic.

Possible phenotypic dosage effect in patients compound heterozygous for FSHD-sized 4q35 alleles

OBJECTIVE

Autosomal dominant facioscapulohumeral muscular dystrophy (FSHD) is associated with a contraction of the D4Z4 repeat array on chromosome 4. So far, homozygosity or compound heterozygosity for FSHD alleles has not been described, and it has been debated whether the absence of such subjects is because of the rarity or the lethality of the disorder.

METHODS

Two unrelated families in which the probands are compound heterozygous for two FSHD-sized alleles were studied. Clinical examination, pulsed-field gel electrophoresis (PFGE) studies of DNA with probes proximal and distal to D4Z4, and cytogenetic analysis of metaphase chromosomes by FISH were performed.

RESULTS

Complementary molecular and cytogenetic approaches confirmed the chromosome 4qA origin of all FSHD-sized repeat arrays that segregate in the families.

CONCLUSIONS

Heterozygosity for FSHD-sized alleles is compatible with life in men and women. A possible dosage effect was observed in both probands in whom each 4qA allele contributed to the FSHD phenotype. Because at least one of the FSHD alleles in both families showed an unusual low penetrance, the authors propose that susceptibility for FSHD is partly determined by intrinsic properties of the disease allele other than the residual D4Z4 repeat size alone.