Transcriptomic insights into multiple system atrophy from a PLP-α-synuclein transgenic mouse model

Multiple system atrophy (MSA) is a rare, neurodegenerative disorder with rapid motor and non-motor symptom progression. MSA is characterized by protein aggregations of α-synuclein found in the cytoplasm of oligodendrocytes. Despite this pathological hallmark, there is still little known about the cause of this disease, resulting in poor treatment options and quality of life post-diagnosis. In this study, we investigated differentially expressed genes (DEGs) via RNA-sequencing of brain samples from a validated PLP-α-synuclein transgenic mouse model, identifying a total of 40 DEGs in the PLP group compared to wild-type (WT), with top detected genes being Gm15446, Mcm6, Aldh7a1 and Gm3435. We observed a significant enrichment of immune pathways and endothelial cell genes among the upregulated genes, whereas downregulated genes were significantly enriched for oligodendrocyte and neuronal genes. We then calculated possible overlap of these DEGs with previously profiled human MSA RNA, resulting in the identification of significant downregulation of the Tsr2 gene. Identifying key gene expression profiles specific to MSA patients is crucial to further understanding the cause, and possible prevention, of this rapidly progressive neurodegenerative disorder.

Efficacy and Safety outcomes of a novel model to assess new medical retina referrals in a high-volume medical retina virtual clinic

BACKGROUND

Ophthalmology outpatient attendances have significantly increased recently with rising pressure from backlogs arising from the pandemic. Medical retina digital surveillance clinics for stable follow-up appointments are well established. We present a model for assessing new referrals and evaluating clinical outcomes and long-term sustainability in a complex high-volume medical retina service.

METHODS

Suitable routine new patient referrals were identified from electronic referrals and referred to this new pathway. Structured history, visual acuities, and intraocular pressures were recorded, and widefield colour fundus and optical coherence tomography imaging were performed at a imaging hub for asynchronous consultant-led review.

RESULTS

1458 patients were invited to attend over four months, with a 13.2% did-not-attend (DNA) rate. Common diagnoses included stable diabetic retinopathy (19.9%), early age-related macular degeneration (6.7%), central serous retinopathy (8.8%), and retinal vein occlusion (6.3%). 7 patients (0.05%) required urgent same-day review. 61 (5.0%) required urgent face-to-face (F2F) assessment within two weeks. A total of 727 (59.0%) were either discharged or remained in the virtual pathway following their first visit.

CONCLUSION

This study encourages the use of a digital model that efficiently assesses suitable newly referred medical retina patients in both complex and local eye unit settings. This decreased the need for F2F clinics and resources. Further patient satisfaction surveys for digital services are currently being evaluated to guide long-term sustainability of this model.

Person-centred care: experiences of older people with dementia

AIM

To explore the views, perceptions and experiences of older people with dementia of person-centred care, and how these might affect practice.

METHOD

This was a qualitative literature review. A literature search was undertaken, which involved searching databases, reference-checking, and hand-searching of academic journals, national policies and nursing organisation websites, from 1999 to 2017. The author undertook data extraction and a meta-synthesis independently to identify themes from the articles.

FINDINGS

A total of 12 articles were included in the literature review. Few articles pertaining to the views, perceptions and experiences of older people with dementia receiving person-centred care were identified, with most of the literature based in settings outside the UK. Four main themes were identified: shared decision-making; promoting individuality, independence and autonomy; person-centred care; and communication and giving voice to people with dementia.

CONCLUSION

Knowledge of the lived experience of people with dementia is important to ensure they receive care that enhances their quality of life. It is essential to consider the views and experiences of older people with dementia to provide effective person-centred care and undertake appropriate research. Further research is required to evaluate the experiences of older people with dementia receiving care to inform practice.

Self-reported knee pain and disability among healthy individuals: reference data and factors associated with the Knee injury and Osteoarthritis Outcome Score (KOOS) and KOOS-Child

OBJECTIVE

To develop normative reference data for the Knee injury and Osteoarthritis Outcome Score (KOOS) and KOOS-Child, as well as investigate socio-demographic, psychological and physical factors associated with knee pain and disability among healthy adults.

METHOD

The KOOS or KOOS-Child (each containing five subscales) was administered to participants aged 8-101 years within the 1000 Norms Project, an observational study of 1000 self-reported healthy individuals. Self-efficacy, physical activity, body mass index (BMI), lower limb alignment, knee frontal plane projection angle (FPPA), knee range of motion (ROM), knee and hip strength, six-minute walk, 30-second chair stand and timed up and down stairs tests were collected. KOOS data were dichotomised using established cut-off scores and logistic regression analyses were conducted for each subscale.

RESULTS

Socio-demographic characteristics were similar to the Australian population. Normative reference data were generated for children (8-17 years) and adults (18-101 years). Female adults were up to twice as likely to report knee pain, symptoms and sport/recreation (Sport/Rec) limitations compared to males (P < .05). Older age, lower self-efficacy, greater BMI, varus lower limb alignment, lower knee flexion ROM and lower hip external rotation (ER) strength were independently associated with knee pain and disability among adults.

CONCLUSIONS

Age- and gender-stratified reference data for the KOOS and KOOS-Child have been developed to guide interpretation of results in practice and research for individuals with knee disorders. Psychological and physical factors are linked with self-reported knee pain/disability among adults, and longitudinal studies to investigate causation are required.

Influence of baseline diabetic retinopathy status on initial anatomical response of intravitreal ranibizumab therapy for diabetic macular oedema

PurposeIntraocular vascular endothelial growth factor (VEGF) levels increases with the severity of diabetic retinopathy. Response of diabetic macular oedema (DMO) to ranibizumab is driven by VEGF suppression. We hypothesised that the initial reduction of central macular thickness by ranibizumab should be maximum in severe diabetic retinopathy until the levels of VEGF decreases to the levels observed in eyes with mild retinopathy.MethodsConsecutive patients with centre-involving DMO (central subfield thickness (CSFT)>300 μm) who had three consecutive monthly ranibizumab injections followed by as needed therapy were included. Retinopathy status was graded as mild non-proliferative diabetic retinopathy (NPDR) (G1), moderate to severe NPDR with no prior panretinal photocoagulation (G2), and treated PDR (G3).ResultsTwo hundred and thirty-nine eyes from 204 patients with a mean age of 64.9 years were included. The distribution was 31.4 G1, 32.2 G2, and 36.4% G3. Mean baseline CSFT for all eyes was 458.5±110.8 μm. Baseline CSFT for G1, G2, and G3, respectively, were 437.6±90.9, 472.3±109.8, and 464.7±124.9 μm (P=0.2155). Mean change in CSFT after three consecutive injections was 128.5±116.6 μm. The mean changes were 95.8±101.4 μm for G1, 137.2±112.9 μm for G2, and 148.9±126.9 μm for G3. The changes in CSFT between groups adjusted for baseline CSFT were statistically significant (P=0.0473). At 6 and 12 months after a mean of 4.5 and 7.7 injections, the changes between groups were no longer significant, P=0.4783 and P=0.8271, respectively.ConclusionsThe initial anatomical response of DMO with intravitreal ranibizumab injections was maximum in eyes with treated PDR, suggesting that the higher the VEGF levels, the better the response with ranibizumab.

Differences in mortality characteristics in neonates with Down's syndrome

OBJECTIVE

Neonates with Down's syndrome (nDS) may have multiple medical issues that place them at increased risk for mortality during the newborn period. Goal of this study was to determine if there are differences in baseline characteristics, medical complications or procedures performed during hospitalization between nDS who survived versus those who died during initial hospitalization.

STUDY DESIGN

Data from 2000 to 2014 were reviewed using the Pediatric Health Information Systems (PHIS) database on all DS patients admitted to the hospital <30 days postnatal life. Baseline demographics, medical complications, procedures performed and mortality were recorded. Patients were divided into nDS patients who were discharged alive (nDS-a) versus nDS patients who died (nDS-d). Multivariate logistic analysis with odds ratios was performed to determine significant predictors of death. A P<0.05 was considered significant.

RESULTS

A total of 5737 nDS were evaluated. Overall mortality was 7.5% (431/5737). nDS-d were more likely than nDS-a to have a lower birth weight (1.0 (0.9 to 1.0)), presence of a diaphragmatic hernia (6.9 (1.9 to 25.1), or a cardiac diagnosis of a pulmonary venous abnormality (6.8 (1.9 to 24.4)), Ebstein's anomaly (3.2 (1.2 to 8.5)) or left-sided obstructive lesion (2.0 (1.3 to 3.0). nDS-d were more likely to develop hydrops (5.7 (3.5 to 9.5)) and necrotizing enterocolitis (1.7 (1.2 to 2.6)). In addition, nDS-d had significantly higher odds of requiring mechanical ventilation (20.7 (9.9 to 43.1)) or extracorporeal membrane oxygenation (8.7 (4.7 to 16.1)).

CONCLUSIONS

A number of characteristics, specifically certain cardiac diagnosis, place nDS at increased risk for mortality. Furthermore, development of specific medical complications or need for particular procedures increases the odds for mortality in nDS. Caregivers should be cognizant that they are taking care of a high-risk population nDS with an increased risk for mortality if these variables are present.

The relationship between area deprivation and contact with community intellectual disability psychiatry

BACKGROUND

People with intellectual disabilities (ID) have high rates of psychiatric illness and are known to live in more deprived areas than the general population. This study investigated the relationship between area deprivation and contact with ID psychiatry.

METHOD

Psychiatric case notes and electronic records were used to identify all patients who had face-to-face contact with community ID psychiatric services over 1 year in the North East Community Health Partnership of Greater Glasgow and Clyde (estimated population 177,867). The Scottish Index of Multiple Deprivation (SIMD) were determined for the patient sample and for the general population living in the same area.

RESULTS

Between 1 June 2012 and 1 June 2013, 184 patients were seen by ID psychiatry over a total of 553 contacts, with valid SIMD data for 179 patients and 543 contacts. Fifty-two per cent of patients (n = 93) lived in the most deprived SIMD decile, and 90.5% (n = 152) in the lowest 5 deciles. Compared with the general population, there were significantly more patients than expected living in the most deprived decile (Fisher's Exact test, P = 0.009) and in the most deprived 5 deciles (Fisher's Exact test, P = 0.001). The median number of contacts was 2 (interquartile range = 1-3). There was no significant association between the number of contacts and SIMD decile. Forty-eight point one per cent (n = 261) of all contacts were with patients living in the most deprived decile and 88.6% (n = 481) in the most deprived 5 deciles. This was significantly more than expected compared with general population data (Fisher's Exact test, P = 0.008 and Fisher's Exact test, P ≤ 0.001).

CONCLUSIONS

In the area under study, contact with ID psychiatry was greater in more deprived areas. Given the high psychiatric morbidity of people with ID, if services do not adjust for deprivation, this may lead to further discrimination in an already disadvantaged population.

Healthcare-associated infections: the value of patient isolation

This article focuses on information about reducing or preventing the transmission of infection from patients with known, suspected or high risk of developing a multidrug-resistant organism infection such as meticillin-resistant Staphylococcus aureus. Since the literature addresses infection prevention and control measures in relation to isolation practices, the literature is evaluated for its effectiveness in supporting patient safety and informing practice that enhances the quality of inpatient care. A review of articles retrieved from several databases is conducted to identify research findings regarding some of the evidence for the effectiveness of isolation in reducing the risk of healthcare-associated infections. The cost, advantages and disadvantages of isolation practices and cohort nursing are also explored, with emphasis on patient wellbeing and safety.

Risk of suicide in patients with dementia: a case study

Evidence indicates that the risk of attempted suicide is a significant issue among people with dementia, however there is a lack of information to guide professional practice. This article uses a case study to reflect on the risk management strategies and ethics of suicide and assisted suicide in relation to a specific patient with dementia. It analyses recommendations aimed at improving the lived experience of people with dementia and those involved in their care, including providing patients with a formal diagnosis as early as possible.

Intestinal location of necrotizing enterocolitis among infants with congenital heart disease

OBJECTIVE

To determine whether differences exist in the location of necrotizing enterocolitis (NEC) in infants with congenital heart disease (CHD) versus those without CHD.

STUDY DESIGN

Retrospective cohort study utilizing 11 years of patient data. Inclusion criterion was surgical exploration for NEC. Presence or absence of CHD was determined. Surgical and/or pathology reports were reviewed to identify the location of NEC. Data were analyzed by t-tests and χ(2) analyses.

RESULT

One hundred and sixty-seven patients met the inclusion criteria. CHD infants had a higher percentage of mortality. There was no difference in the location of NEC between non-CHD and CHD patients, with the predominant location being the small intestine in both. In addition, there was no difference in the location of NEC between preterm non-CHD patients and full-term CHD patients with the small intestine again being the primary site.

CONCLUSION

Despite differences in gestational age between non-CHD and CHD patients, the location of NEC in these infants did not differ.

Recruitment to intellectual disability research: a qualitative study

BACKGROUND

Difficulties in the recruitment of adults with intellectual disability (ID) to research studies are well described but little studied. The aim of this study was to investigate the difficulties in recruiting to a specific research project, in order to inform future recruitment to ID research.

METHODS

Individual semi-structured interviews were held between September 2009 and May 2010 with people who had been involved as intermediaries in recruitment to the research project. These were transcribed verbatim and were independently analysed by two researchers using the Framework approach, who then agreed upon the key emerging themes.

RESULTS

Ten interviews were analysed. A number of themes arose, including participant factors (interview anxiety, difficulties in understanding the concept of research, worry about negative feedback), the importance of the researcher (using a personal approach, meeting potential participants prior to recruitment) and motivators [enjoyment of the research interview (participant), obtaining a medical assessment (carer)]. The themes were then used to generate strategies to improve recruitment to ID research: these include the research team applying a more personal approach, developing the recruitment process to allow for multiple meetings with potential participants, and considering motivators for both participants and carers.

CONCLUSIONS

This study has used the experiences of intermediaries to identify strategies for improving recruitment to future ID research. This has implications in terms of both time and money. However, successful recruitment is essential to ID research, and we hope that the study will be used by ID researchers to review and improve their recruitment processes.

Social exclusion and people with intellectual disabilities: a rural-urban comparison

BACKGROUND

Research suggests that social exclusion is a problem both for people with intellectual disabilities (ID) and for people living in rural areas. This may give rise to a double disadvantage for people with ID living in rural areas. Conversely, aspects of rural life such as community spirit and social support may protect against social exclusion in this population. This study was designed to compare a number of measures of social exclusion in adults with ID living in rural and urban areas, with the aim of identifying whether a double disadvantage exists.

METHOD

Adults with ID were recruited from a rural and an urban area in Scotland. Participants participated in a face-to-face interview and their medical notes were accessed. Social exclusion was investigated using a number of measures comprising: daytime opportunities and physical access to community facilities (using part of the British Institute of Learning Disabilities questionnaire), recent contact with others and the quality of personal relationships (using a modified Interview Measure of Social Relationships questionnaire) and area deprivation by postcode (using the Scottish Index of Multiple Deprivation). The data were analysed using a series of binary logistic regression models that adjusted for variables including age, gender, level of ID, mental illhealth and common physical co-morbidities.

RESULTS

A representative sample of adults with ID from rural (n = 39) and urban (n = 633) areas participated. Participants from rural areas were significantly more likely to have any regular daytime opportunity [odds ratio (OR) = 10.8, 95% CI = 2.3-51.5] including employment (OR = 22.1, 95% CI = 5.7-85.5) and attending resource centres (OR = 6.7, 95% CI = 2.6-17.2) than were participants from urban areas. They were also more likely to have been on holiday (OR = 17.8, 95% CI = 4.9-60.1); however, were less likely to use community facilities on a regular basis. Participants from urban and rural areas had a similar number of contacts with other people in a wide range of situations, but the quality of relationships may have been less close in rural areas. Finally, participants lived in significantly less deprived areas when in rural compared with urban areas (Mann-Whitney U = 7826, Z = -3.675, P ≤ 0.001).

CONCLUSIONS

These results suggest that adults with ID living in rural areas have better opportunities and live in less deprived areas than adults with ID living in urban areas. However, they may not hold such positive or close relationships, and this may be important when considering the subjective experience of social exclusion.

Therapy-induced clearance of HCV core antigen from plasma predicts an end of treatment viral response

During viral assembly, viral proteins are released into plasma and can be used to infer viral load. The Architect hepatitis C virus (HCV) core antigen (Ag) assay is a potential alternative to HCV RNA quantification for measuring response to therapy and predicting an end of treatment viral response (EOTR). The HCVp22Ag assay was used to infer viral load in 68 window RNA-containing samples and in 284 samples from baseline to week 14 of ribavirin/interferon treatment in 23 patients with EOTR including three who relapsed, 20 not achieving EOTR and 11 controls. HCV Ag and RNA correlated well (r = 0.86) with linear dose responses on dilution. In patients on therapy and control patients, plasma HCV antigen was detected in 51 of 54 with an interpolated LOD cut off between 10(3) and 10(4) RNA IU/mL. Plasma HCV antigenaemia and plasma RNA levels were significantly different in EOTR from non-EOTR patients at 3 days after treatment start and all times thereafter. Positive and negative EOTR predictive values for HCV RNA >2 log drop and HCV Ag loss at 12 weeks were 70% and 74%, 85% and 93% respectively. HCV Ag reactivity has a linear dose response independent of genotype and correlates well with HCV RNA. The failure to clear HCV Ag is as accurate as the failure to clear HCV RNA at twelve weeks into therapy in predicting the likelihood of failure to achieve EOTR. HCV Ag potentially offers a convenient alternative to RNA measurement for defining a futility flag in HCV therapy.

Alzheimer's disease-related loss of Pin1 function influences the intracellular localization and the processing of AβPP

Increased amyloidogenic processing of the amyloid-β protein precursor (AβPP) is a characteristic of Alzheimer's disease (AD). We previously observed that the prolyl isomerase Pin1, which is down-regulated in AD, regulates AβPP conformation accelerating cis/trans isomerization of the phospho-Thr668-Pro669 peptide bond, and that Pin1 knockout in mice increases the amyloidogenic processing of AβPP, although the underlying mechanism is still unknown. Since the intracellular localization of AβPP determines whether the processing will be amyloidogenic or non-amyloidogenic, here we addressed the question whether loss of Pin1 function affects the intracellular localization of AβPP, influencing AβPP processing. Using cellular models of Pin1 knockout and Pin1 knockdown, we have demonstrated that lowering Pin1 levels changed the intracellular localization and the processing of AβPP. Under these conditions, less AβPP was retained at the plasma membrane favoring the amyloidogenic processing, and the kinetics of AβPP internalization increased as well as the nuclear trafficking of AβPP C-terminal fragment AICD. In addition, AβPPThr668Ala mutant, which cannot bind to Pin1 and retains more trans conformation, rescued the levels of AβPP at the plasma membrane in Pin1 knockout cells. Thus, loss of Pin1 function contributes to amyloidogenic pathways, by facilitating both the removal of AβPP from compartments where it is mostly non-amyloidogenic and its internalization to more amyloidogenic compartments. These data suggest that physiological levels of Pin1 are important to control the intracellular localization and metabolic fate of Thr668-phosphorylated AβPP, and regulation of AβPP conformation is especially important in pathologic conditions of AβPP hyperphosphorylation and/or loss of Pin1 function, associated with AD.

Proline isomer-specific antibodies reveal the early pathogenic tau conformation in Alzheimer's disease

cis-trans isomerization of proteins phosphorylated by proline-directed kinases is proposed to control numerous signaling molecules and is implicated in the pathogenesis of Alzheimer's and other diseases. However, there is no direct evidence for the existence of cis-trans protein isomers in vivo or for their conformation-specific function or regulation. Here we develop peptide chemistries that allow the generation of cis- and trans-specific antibodies and use them to raise antibodies specific for isomers of phosphorylated tau. cis, but not trans, p-tau appears early in the brains of humans with mild cognitive impairment, accumulates exclusively in degenerated neurons, and localizes to dystrophic neurites during Alzheimer's progression. Unlike trans p-tau, the cis isomer cannot promote microtubule assembly, is more resistant to dephosphorylation and degradation, and is more prone to aggregation. Pin1 converts cis to trans p-tau to prevent Alzheimer's tau pathology. Isomer-specific antibodies and vaccines may therefore have value for the early diagnosis and treatment of Alzheimer's disease.

Arginine deprivation and argininosuccinate synthetase expression in the treatment of cancer

Arginine, a semi-essential amino acid in humans, is critical for the growth of human cancers, particularly those marked by de novo chemoresistance and a poor clinical outcome. In addition to protein synthesis, arginine is involved in diverse aspects of tumour metabolism, including the synthesis of nitric oxide, polyamines, nucleotides, proline and glutamate. Tumoural downregulation of the enzyme argininosuccinate synthetase (ASS1), a recognised rate-limiting step in arginine synthesis, results in an intrinsic dependence on extracellular arginine due to an inability to synthesise arginine for growth. This dependence on extracellular arginine is known as arginine auxotrophy. Several tumours are arginine auxotrophic, due to variable loss of ASS1, including hepatocellular carcinoma, malignant melanoma, malignant pleural mesothelioma, prostate and renal cancer. Importantly, targeting extracellular arginine for degradation in the absence of ASS1 triggers apoptosis in arginine auxotrophs. Several phase I/II clinical trials of the arginine-lowering drug, pegylated arginine deiminase, have shown encouraging evidence of clinical benefit and low toxicity in patients with ASS1-negative tumours. In part, ASS1 loss is due to epigenetic silencing of the ASS1 promoter in various human cancer cell lines and tumours, and it is this silencing that confers arginine auxotrophy. In relapsed ovarian cancer, this is associated with platinum refractoriness. In contrast, several platinum sensitive tumours, including primary ovarian, stomach and colorectal cancer, are characterised by ASS1 overexpression, which is regulated by proinflammatory cytokines. This review examines the prospects for novel approaches in the prevention, diagnosis and treatment of malignant disease based on ASS1 pathophysiology and its rate-limiting product, arginine.

The Effect of Dexmedetomidine on Agitation during Weaning of Mechanical Ventilation in Critically ill Patients

Ventilated patients receiving opioids and/or benzodiazepines are at high risk of developing agitation, particularly upon weaning towards extubation. This is often associated with an increased intubation time and length of stay in the intensive care unit and may cause long-term morbidity. Anxiety, fear and agitation are amongst the most common non-pulmonary causes of failure to liberate from mechanical ventilation. This prospective, open-label observational study examined 28 ventilated adult patients in the intensive care unit (30 episodes) requiring opioids and/or sedatives for >24 hours, who developed agitation and/or delirium upon weaning from sedation and failed to achieve successful extubation with conventional management. Patients were ventilated for a median (interquartile range) of 115 [87 to 263] hours prior to enrolment, Dexmedetomidine infusion was commenced at 0.4 μg/kg/hour for two hours, after which concurrent sedative therapy was preferentially weaned and titrated to obtain target Motor Activity Assessment Score score of 2 to 4. The median (range) maximum dose and infusion time of dexmedetomidine was 0.7 μg/kg/hour (0.4 to 1.0) and 62 hours (24 to 252) respectively. The number of episodes at target Motor Activity Assessment Score score at zero, six and 12 hours after commencement of dexmedetomidine were 7/30 (23.3%), 28/30 (93.3%) and 26/30 (86.7%), respectively (P <0.001 for 6 and 12 vs 0 hours). Excluding unrelated clinical deterioration, 22 episodes (73.3%) achieved successful weaning from ventilation with a median (interquartile range) ventilation time of 70 (28 to 96) hours after dexmedetomidine infusion. Dexmedetomidine achieved rapid resolution of agitation and facilitated ventilatory weaning after failure of conventional therapy. Its role as first-line therapy in ventilated, agitated patients warrants further investigation.

Male-to-male transmission of Costello syndrome: G12S HRAS germline mutation inherited from a father with somatic mosaicism

Costello syndrome is a rare congenital anomaly syndrome associated with mental retardation and predisposition to benign and malignant tumors, caused by heterozygous missense mutations in the HRAS oncogene. Previously, all molecularly analyzed mutations appeared de novo, and most arose in the paternal germline. A single patient with somatic mosaicism for a Costello syndrome causing HRAS mutation has been reported. Here we describe the first documented transmission of an HRAS mutation from a parent with somatic mosaicism to a child with typical Costello syndrome. Prior to the identification of the underlying gene mutation in Costello syndrome, this family had been identified clinically. The proband was subsequently found to carry a G12S HRAS germline mutation. Testing of the parents for parental origin identified his father as mosaic for the same HRAS mutation. The mother was found not to carry an HRAS mutation. The causative familial mutation is identified as a c.34G > A, which is the most common mutation in the HRAS gene in patients with Costello syndrome. The father carries the mutation in 7-8% of his alleles. This is the second case of mosaicism observed in Costello syndrome and the first direct molecular evidence of father-to-son transmission of the disease-causing mutation. Our observation underlines the importance of parental evaluation, and may have implications for genetic counseling and clinical practice.

Expanding the phenotype of SPONASTRIME dysplasia to include short dental roots, hypogammaglobulinemia, and cataracts

SPONASTRIME dysplasia (SD) is an autosomal recessive skeletal dysplasia of the spondyloepimetaphyseal dysplasia (SEMD) type. The name was derived from "spondylar and nasal alterations with striated metaphyses" [Fanconi et al. 1983; Helv Paediat Acta 38: 267-280]. We follow two previously reported patients with SD [Patients 3, 4 in Langer et al. 1996; Am J Med Genet 63: 20-27]. Since the original publication, additional findings were identified in these patients.

Further delineation of the phenotype resulting fromBRAForMEK1germline mutations helps differentiate cardio-facio-cutaneous syndrome from Costello syndrome

Because Cardio-facio-cutaneous (CFC) syndrome has significant phenotypic overlap with Costello syndrome, it may be difficult to establish the diagnosis on a clinical basis. The recent discoveries of germline HRAS mutations in patients with Costello syndrome and mutations in BRAF, MEK1, and MEK2 in CFC syndrome uncovered the biologic mechanism for the shared phenotypic findings based on the close interaction of the affected gene products within the MAP kinase pathway. We evaluated a series of patients who were either clinically diagnosed with Costello syndrome, or in whom the diagnoses of both Costello and CFC syndromes were considered. After excluding mutations in HRAS, we identified eight changes in BRAF and five in MEK1. Five mutations are novel, and all changes occurred de novo among those triads tested. A review of the clinical abnormalities showed important differences between patients with either a BRAF or MEK1 mutation, and those previously reported with an HRAS mutation. Statistical significance was achieved, despite the relatively small number of patients with BRAF and MEK1 mutations reported here, for polyhydramnios, growth hormone deficiency and the presence of more than one papilloma, which were less common in CFC compared to HRAS mutation positive patients. Although both CFC and Costello syndrome are characterized by cardiac abnormalities in about three-fourths of patients, the pattern of congenital heart defects (CHD), hypertrophic cardiomyopathy (HCM), and tachycardia differs somewhat. CHD, especially pulmonic stenosis associated with a secundum-type atrial septal defect, are more common in CFC than Costello syndrome (P = 0.02). Atrial tachycardia is less frequent in CFC patients with BRAF or MEK1 mutations, compared to Costello syndrome patients with HRAS mutation (P = 0.04). Chaotic atrial rhythm or multifocal atrial tachycardia was observed only in Costello syndrome. Malignant tumors have been viewed as characteristic for Costello syndrome due to HRAS mutations, however, we report here on a MEK1 mutation in a patient with a malignant tumor, a hepatoblastoma. Although this indicates that the presence of a tumor is not specific for Costello syndrome with HRAS mutation, it is noteworthy that the tumor histology differs from those commonly seen in Costello syndrome. Based on these clinical differences we suggest that patients with BRAF and MEK mutations should be diagnosed with CFC syndrome, and the diagnosis of Costello syndrome be reserved for patients with HRAS mutations.

Candidate loci for Zimmermann-Laband syndrome at 3p14.3

A male with 46,XY,t(3;17)(p14.3;q24.3) presented with gingival hyperplasia, hypertrichosis, unusually large ears and marked hypertrophy of the nose, characteristic of the Zimmermann-Laband syndrome (ZLS). Other features include large facial bones and mandibles, large protruding upper lip, enlarged fingers and toes, strabismus, and enlarged phallus. Knowledge of a 46,XX,t(3;8)(p21.2;q24.3) reported previously in a mother and daughter with ZLS suggests that the 3p14.3-p21.2 region may contain a gene responsible for ZLS. We have reassessed the chromosome 3 breakpoint region of the t(3;8) and revised its breakpoint location to 3p14.3, based upon an updated human genome sequence assembly. Using fluorescence in situ hybridization (FISH) with BAC clones, we have also identified a breakpoint spanning clone at 3p14.3 in our t(3;17) patient, thereby narrowing the breakpoint to a region of approximately 200 kb. These data suggest that the gene responsible for ZLS is located in 3p14.3 and implicates four likely candidate genes in this region: CACNA2D3, encoding a voltage-dependent calcium channel, LRTM1, a gene of unknown function embedded within CACNA2D3, WNT5A, encoding a secreted signaling protein of the WNT family, and ERC2, which codes for a synapse protein.

A randomized controlled clinical trial to determine the optimum duration of G-CSF priming prior to BM stem cell harvesting

BACKGROUND

Harvesting of hemopoietic stem cells (HSC) from G-CSF-primed BM for autologous transplantation is an alternative to collection of unprimed BM or G-CSF-primed peripheral blood (PB). However, the optimum number of days of G-CSF administration for this purpose is unknown. We set out to determine whether cell yields could be optimized by varying the number of days of G-CSF administration prior to BM stem cell harvesting.

METHODS

We conducted a randomized controlled single-center trial of 6 days (the standard) vs. 4 days of G-CSF administration and compared yields of total nucleated cells (TNC), CD34(+) HSC and CFU-GM cells per kilogram patient body weight. Statistical analysis was by Student's t-test.

RESULTS

Twenty-four patients were enrolled; 13 received 6 days and 11 received 4 days of G-CSF administration. Analysis of the first harvest aspirate showed higher proportions of CD34(+) HSC (P=0.02) and CFU-GM (P=0.03) in the 4-day group. For the 6-day and 4-day groups, respectively, the median yield of TNC/kg was 6.5 x 10(8) and 5.4 x 10(8) (P=0.28), of CD34(+) cells/kg 0.56 x 10(6) and 0.98 x 10(6) (P=0.04) and of CFU-GM cells/kg 1.66 x 10(5) and 1.55 x 10(5) (P=0.75).

DISCUSSION

These results suggest that by 6 days the HSC-stimulating effect of G-CSF has passed its peak and that 4 days should be adopted as the standard for G-CSF priming prior to BM stem cell harvesting for autologous transplantation.

Somatic mosaicism for an HRAS mutation causes Costello syndrome

De novo heterozygous HRAS point mutations have been reported in more than 81 patients with Costello syndrome (CS), but genotype/phenotype correlation remains incomplete because the majority of patients share a common mutation, G12S, seen in 65/81 (80%). Somatic HRAS mutations have previously been identified in solid tumors, and mutation hot spots related to a gain-of-function effect of the gene product are known. The germline mutations causing CS occur at these hot spots and convey a gain-of-function effect, thus accounting for the greatly increased cancer risk. Diagnostic testing for HRAS mutations is now available and the identification of a mutation in a patient with consistent clinical findings confirms a diagnosis of CS. It is not clear yet if the absence of an HRAS mutation precludes a diagnosis of CS. Because there is a significant overlap in the clinical findings of Costello, cardio-facio-cutaneous, and Noonan syndromes, diagnostic uncertainty remains in patients lacking an HRAS mutation. We report here on a female with findings suggestive of CS in whom mutation analysis performed with standard techniques on white blood cell derived DNA did not show an HRAS mutation. However, analysis of DNA derived from three independently collected buccal swabs showed a sequence change qualitatively consistent with the G12S mutation. Allelic quantitation showed the presence of the mutation in approximately 25%-30% of the sampled buccal cells. In this patient, standard technology failed to identify the disease causing mutation on DNA derived from a blood sample, highlighting the potential pitfalls in the interpretation of negative mutation studies. This is the first reported CS patient mosaic for the common HRAS mutation, likely due to a somatic mutation occurring very early in fetal development.

Frontometaphyseal dysplasia: mutations in FLNA and phenotypic diversity

Frontometaphyseal dysplasia is an X-linked trait primarily characterized by a skeletal dysplasia comprising hyperostosis of the skull and modeling anomalies of the tubular bones. Extraskeletal features include tracheobronchial, cardiac, and urological malformations. A proportion of individuals have missense mutations or small deletions in the X-linked gene, FLNA. We report here our experience with comprehensive screening of the FLNA gene in a group of 23 unrelated probands (11 familial instances, 12 simplex cases; total affected individuals 32) with FMD. We found missense mutations leading to substitutions in the actin-binding domain and within filamin repeats 9, 10, 14, 16, 22, and 23 of filamin A in 13/23 (57%) of individuals in this cohort. Some mutations present with a male phenotype that is characterized by a severe skeletal dysplasia, cardiac, and genitourinary malformations that leads to perinatal death. Although no phenotypic feature consistently discriminates between females with FMD who are heterozygous for FLNA mutations and those in whom no FLNA mutation can be identified, there is a difference in the degree of skewing of X-inactivation between these two groups. This observation suggests that locus heterogeneity may exist for this disorder.

Paternal bias in parental origin ofHRASmutations in Costello syndrome

Costello syndrome (CS) is a rare congenital condition caused by heterozygous de novo missense mutations affecting the codon for glycine 12 or 13 of the HRAS gene. We have identified 39 CS patients harboring the p.Gly12Ser mutation (NM_005343.2:c.34 G > A), two patients with c.35G > C mutations resulting in p.Gly12Ala substitutions, and one patient carrying the p.Gly13Cys substitution (c.37G > A). We analyzed the region flanking the mutated sites in 42 probands and 59 parents, and used four polymorphic markers to trace the parental origin of the germline mutations: one highly polymorphic hexanucleotide (GGGCCT) repeat region, defining three alleles with different numbers of repeat units (two, three, or four), and three SNPs. One of the SNPs, rs12628 (c.81T > C), was found in strong linkage disequilibrium with the hexanucleotide repeat region. Out of a total of 24 probands with polymorphic markers, 16 informative families were tested and the paternal origin of the germline mutation was found in 14 CS probands; a distribution that is neither consistent with an equal likelihood of mutations arising in either parent (P = 0.0018), nor with exclusive paternal origin.

The use of viral vectors to produce hepatitis B virus core particles in plants

The expression and assembly of the hepatitis B virus (HBV) nucleocapsid protein (HBcAg) were investigated in plants using viral vectors. Constructs based on either Potato virus X (PVX) or Cowpea mosaic virus (CPMV) containing the sequence of HBcAg were able to infect the appropriate host plants and remained genetically stable during infection. Analysis of HBcAg expression revealed that the protein can self-assemble into core-like particles and that the assembled material could be partially purified by differential centrifugation. Thus, the use of viral vectors can be considered a practical method for rapid production of assembled HBcAg particles in plants. This approach provides a means whereby a variety of chimaeric particles can be assessed quickly and cheaply for various diagnostic and vaccine applications.

Recent Progress in Plantibody Technology

Antibodies are an important class of proteins that can be used for the prevention, treatment and diagnosis of many diseases. Consequently, there is an intense and growing demand for recombinant antibodies, placing immense pressure on current production capacity which is based largely on microbial cultures and mammalian cells. Alternative systems for cost effective antibody production would be very welcome, and plants are now gaining widespread acceptance as green bioreactors with advantages in terms of cost, scalability and safety. Several plant-produced antibodies (plantibodies) are undergoing clinical trials and the first commercial approval could be only a few years away. The performance of the first generation of products has been very encouraging so far. In terms of product authenticity, differences in glycosylation between plantibodies and their mammalian counterparts have been defined, and the scientific evaluation of any possible consequences is underway. Ongoing studies are addressing the remaining biochemical constraints, and aim to further improve product yields, homogeneity and authenticity, particularly where the antibody is intended for injection into human patients. A remaining practical challenge is the implementation of large-scale production and processing under good manufacturing practice conditions that are yet to be endorsed by regulatory bodies. The current regulatory uncertainty and the associated costs represent an entry barrier for the pharmaceutical industry. However, the favourable properties of plants are likely to make the plant systems a useful alternative for small, medium and large scale production throughout the development of new antibody-based pharmaceuticals.

Observation of a parental inversion variant in a rare Williams-Beuren syndrome family with two affected children

The Williams-Beuren syndrome (WBS) region at 7q11.23 is subject to several genomic rearrangements, one of which, the WBSinv-1 variant, is an inversion polymorphism. The WBSinv-1 chromosome has been shown to occur frequently in parents of individuals with WBS, implying that it predisposes the region to the WBS deletion. Here we investigate two WBS families with multiple affected children, and show that in one family, both siblings have a deletion on a WBSinv-1 chromosome background that arose due to interchromosomal recombination. These results suggest that the two WBS deletions in this family were independent events, and that there is likely a significant increase in the risk of deletion of the WBS region associated with the WBSinv-1 chromosome. The rarity of multiplex WBS families would suggest that the overall risk of having a child with WBS is still relatively low; however, families with an existing member with WBS may choose to opt for WBSinv-1 testing and genetic counseling.

Filamin A mutations cause periventricular heterotopia with Ehlers-Danlos syndrome

OBJECTIVE

To define the clinical, radiologic, and genetic features of periventricular heterotopia (PH) with Ehlers-Danlos syndrome (EDS).

METHODS

Exonic sequencing and single stranded conformational polymorphism (SSCP) analysis was performed on affected individuals. Linkage analysis using microsatellite markers on the X-chromosome was performed on a single pedigree. Western blotting evaluated for loss of filamin A (FLNA) protein and Southern blotting assessed for any potential chromosome rearrangement in this region.

RESULTS

The authors report two familial cases and nine additional sporadic cases of the EDS-variant form of PH, which is characterized by nodular brain heterotopia, joint hypermobility, and development of aortic dilatation in early adulthood. MRI typically demonstrated bilateral nodular PH, indistinguishable from PH due to FLNA mutations. Exonic sequencing or SSCP analyses of FLNA revealed a 2762 delG single base pair deletion in one affected female. Another affected female harbored a C116 single point mutation, resulting in an A39G change. A third affected female had a 4147 delG single base pair deletion. One pedigree with no detectable exonic mutation demonstrated positive linkage to the FLNA locus Xq28, an affected individual in this family also had no detectable FLNA protein, but no chromosomal rearrangement was detected.

CONCLUSION

These results suggest that the Ehlers-Danlos variant of periventricular heterotopia (PH), in part, represents an overlapping syndrome with X-linked dominant PH due to filamin A mutations.

HRAS mutation analysis in Costello syndrome: Genotype and phenotype correlation

Costello syndrome is a rare condition comprising mental retardation, distinctive facial appearance, cardiovascular abnormalities (typically pulmonic stenosis, hypertrophic cardiomyopathy, and/or atrial tachycardia), tumor predisposition, and skin and musculoskeletal abnormalities. Recently mutations in HRAS were identified in 12 Japanese and Italian patients with clinical information available on 7 of the Japanese patients. To expand the molecular delineation of Costello syndrome, we performed mutation analysis in 34 North American and 6 European (total 40) patients with Costello syndrome, and detected missense mutations in HRAS in 33 (82.5%) patients. All mutations affected either codon 12 or 13 of the protein product, with G12S occurring in 30 (90.9%) patients of the mutation-positive cases. In two patients, we found a mutation resulting in an alanine substitution in position 12 (G12A), and in one patient, we detected a novel mutation (G13C). Five different HRAS mutations have now been reported in Costello syndrome, however genotype-phenotype correlation remains incomplete.