Delineating the phenotypic spectrum of Bainbridge-Ropers syndrome: 12 new patients with de novo, heterozygous, loss-of-function mutations in ASXL3 and review of published literature

BACKGROUND

Bainbridge-Ropers syndrome (BRPS) is a recently described developmental disorder caused by de novo truncating mutations in the additional sex combs like 3 (ASXL3) gene. To date, there have been fewer than 10 reported patients.

OBJECTIVES

Here, we delineate the BRPS phenotype further by describing a series of 12 previously unreported patients identified by the Deciphering Developmental Disorders study.

METHODS

Trio-based exome sequencing was performed on all 12 patients included in this study, which found a de novo truncating mutation in ASXL3. Detailed phenotypic information and patient images were collected and summarised as part of this study.

RESULTS

By obtaining genotype:phenotype data, we have been able to demonstrate a second mutation cluster region within ASXL3. This report expands the phenotype of older patients with BRPS; common emerging features include severe intellectual disability (11/12), poor/ absent speech (12/12), autistic traits (9/12), distinct face (arched eyebrows, prominent forehead, high-arched palate, hypertelorism and downslanting palpebral fissures), (9/12), hypotonia (11/12) and significant feeding difficulties (9/12) when young.

DISCUSSION

Similarities in the patients reported previously in comparison with this cohort included their distinctive craniofacial features, feeding problems, absent/limited speech and intellectual disability. Shared behavioural phenotypes include autistic traits, hand-flapping, rocking, aggressive behaviour and sleep disturbance.

CONCLUSIONS

This series expands the phenotypic spectrum of this severe disorder and highlights its surprisingly high frequency. With the advent of advanced genomic screening, we are likely to identify more variants in this gene presenting with a variable phenotype, which this study will explore.

High frequency of mitochondrial DNA mutations in HIV-infected treatment-experienced individuals

OBJECTIVES

We recently observed a decrease in deoxyribonucleotide (dNTP) pools in HIV-infected individuals on antiretroviral therapy (ART). Alterations in dNTPs result in mutations in mitochondrial DNA (mtDNA) in cell culture and animal models. Therefore, we investigated whether ART is associated with mitochondrial genome sequence variation in peripheral blood mononuclear cells (PBMCs) of HIV-infected treatment-experienced individuals.

METHODS

In this substudy of a case-control study, 71 participants were included: 22 'cases', who were HIV-infected treatment-experienced patients with mitochondrial toxicity, 25 HIV-infected treatment-experienced patients without mitochondrial toxicity, and 24 HIV-uninfected controls. Total DNA was extracted from PBMCs and purified polymerase chain reaction (PCR) products were subjected to third-generation sequencing using the PacBio Single Molecule Real-Time (SMRT) sequencing technology. The sequences were aligned against the revised Cambridge reference sequence for human mitochondrial DNA (NC_012920.1) for detection of variants.

RESULTS

We identified a total of 123 novel variants, 39 of them in the coding region. HIV-infected treatment-experienced patients with and without toxicity had significantly higher average numbers of mitochondrial variants per participant than HIV-uninfected controls. We observed a higher burden of mtDNA large-scale deletions in HIV-infected treatment-experienced patients with toxicity compared with HIV-uninfected controls (P = 0.02). The frequency of mtDNA molecules containing a common deletion (mt.δ4977) was higher in HIV-infected treatment-experienced patients with toxicity compared with HIV-uninfected controls (P = 0.06). There was no statistically significant difference in mtDNA variants between HIV-infected treatment-experienced patients with and without toxicity.

CONCLUSIONS

The frequency of mtDNA variants (mutations and large-scale deletions) was higher in HIV-infected treatment-experienced patients with or without ART-induced toxicity than in uninfected controls.

Large-scale discovery of novel genetic causes of developmental disorders

Despite three decades of successful, predominantly phenotype-driven discovery of the genetic causes of monogenic disorders, up to half of children with severe developmental disorders of probable genetic origin remain without a genetic diagnosis. Particularly challenging are those disorders rare enough to have eluded recognition as a discrete clinical entity, those with highly variable clinical manifestations, and those that are difficult to distinguish from other, very similar, disorders. Here we demonstrate the power of using an unbiased genotype-driven approach to identify subsets of patients with similar disorders. By studying 1,133 children with severe, undiagnosed developmental disorders, and their parents, using a combination of exome sequencing and array-based detection of chromosomal rearrangements, we discovered 12 novel genes associated with developmental disorders. These newly implicated genes increase by 10% (from 28% to 31%) the proportion of children that could be diagnosed. Clustering of missense mutations in six of these newly implicated genes suggests that normal development is being perturbed by an activating or dominant-negative mechanism. Our findings demonstrate the value of adopting a comprehensive strategy, both genome-wide and nationwide, to elucidate the underlying causes of rare genetic disorders.

Calpain inhibition mediates autophagy-dependent protection against polyglutamine toxicity

Over recent years, accumulated evidence suggests that autophagy induction is protective in animal models of a number of neurodegenerative diseases. Intense research in the field has elucidated different pathways through which autophagy can be upregulated and it is important to establish how modulation of these pathways impacts upon disease progression in vivo and therefore which, if any, may have further therapeutic relevance. In addition, it is important to understand how alterations in these target pathways may affect normal physiology when constitutively modulated over a long time period, as would be required for treatment of neurodegenerative diseases. Here we evaluate the potential protective effect of downregulation of calpains. We demonstrate, in Drosophila, that calpain knockdown protects against the aggregation and toxicity of proteins, like mutant huntingtin, in an autophagy-dependent fashion. Furthermore, we demonstrate that, overexpression of the calpain inhibitor, calpastatin, increases autophagosome levels and is protective in a mouse model of Huntington's disease, improving motor signs and delaying the onset of tremors. Importantly, long-term inhibition of calpains did not result in any overt deleterious phenotypes in mice. Thus, calpain inhibition, or activation of autophagy pathways downstream of calpains, may be suitable therapeutic targets for diseases like Huntington's disease.

Patients' perspective of wide-awake hand surgery--100 consecutive cases

The wide-awake hand surgery (WAHS) technique involves injecting lidocaine with adrenaline for hand surgical procedures that are done without the use of tourniquets, sedation, regional or general anaesthetic. This is a retrospective review of the first 100 consecutive patients who underwent operations using this technique at our centre. The operations included carpal and cubital tunnel decompression, trapeziectomy, tendon transfer, and tenolysis. A questionnaire adapted from Lalonde's previous work on wide-awake surgery was used to assess patients' experiences. Sixty-five percent of the patients responded to the postal questionnaire, the majority reporting a high satisfaction level. Ninety-one percent of responders reported that the operation was less painful or comparable with a procedure at the dentist; 86% would prefer to be wide-awake if they needed to have hand surgery again, and 90% stated they would recommend WAHS to a friend.

Trial of ligation versus coagulation of lymphatics in dynamic inguinal sentinel lymph node biopsy for staging of squamous cell carcinoma of the penis

INTRODUCTION

Te principal advantage of dynamic sentinel lymph node biopsy (DSNB) over modified inguinal node dissection is the lower complication rate. The aim of this study was to identify factors associated with short-term complications of DSNB in order to lower morbidity of the procedure.

METHODS

Retrospective and prospective cohort studies were performed on patients undergoing DSNB between April 2005 and March 2010. Patients were categorised into three groups of 50 (from a total of 250 patients on the database). The patients of Group A, on whom ligaclips were the lymphovascular control technique, were compared with those of Group B, in whom diathermy was used. Incision length, operative time, number of nodes removed, antibiotics and co-morbidities were recorded. A prospective study on Group C, using ligaclips, was also performed.

RESULTS

Groups A (88 groins), B (75 groins) and C (68 groins) were explored with complication rates of 5.7%, 24.0% (p=0.0018) and 8.8% (p=0.0277). Co-morbidities, antibiotics (co-amoxiclav 1.2g intravenous as per protocol) and the mean number of nodes removed were similar in all groups. The mean incision length was 4.1cm (standard deviation [SD]: 1.0cm) for Group A, 5.6cm (SD: 1.0cm) for Group B (p=0.0001) and 5.6cm (SD: 0.8cm) for Group C (p=0.979). The mean operative times for Groups A, B and C were 15.8 (SD: 8.1), 19.3 (SD: 7.4) (p=0.0043) and 22.1 (SD: 7.7) (p=0.0301) minutes respectively.

CONCLUSIONS

Lymphovascular control with diathermy is associated with a statistically higher short-term complication rate compared with ligaclip usage (ie ‘permanent’ ligation). Lymphocoeles are the principal complication and can result in delayed wound infection and breakdown. A small but statistical increase in operative time and wound length is likely to be related to registrar training.

MO-F-213AB-05: Commissioning of Gated RapidArc Radiotherapy for Treatment of Moving Targets

PURPOSE

To commission and evaluate gated RapidArc radiotherapy of a linear accelerator (Varian TrueBeam) for treatment of moving targets using a programmable dynamic phantom.

METHODS

The phantom used had different dosimetry inserts for measurement of dose and dose distribution. It could be programmed to move in the anterior-posterior and superior-inferior axes with different motion patterns, amplitudes and frequencies to simulate lung motions of patients. A set of 4D CT images was acquired with the aid of a Varian RPM system. Images acquired at the 40, 50 and 60% of the motion cycle were selected and transferred to a treatment planning system (Varian Eclipse) for planning. A two-arc RapidArc treatment plan was generated for a C-shaped target volume with a conformity index of 1.49 and transferred to the TrueBeam for treatment delivery. Dose and dose distribution measurements were performed using a 0.057 cc ionization chamber and radiochromic films, respectively and compared with the TPS calculations. Five treatment fractions were given in three days with two different target motion patterns to assess the consistency of the dose delivery.

RESULTS

Agreement between TPS calculation and measurement were within 1.64% for dose and 3% or 3mm in distance to agreement for dose distribution. Repeatability of dose delivery between treatments was within 0.1% (1SD) in the five treatment fractions delivered in three days. The time required to deliver a dose of 2 Gy to a moving C-shaped target using gated RapidArc technique with two gantry rotations was about 15 minutes.

CONCLUSIONS

The geometric and dosimetric accuracy and consistency of gated RapidArc radiotherapy had been verified. Our study indicated that the accuracy and consistency of the treatment modality were acceptable for clinical implementation.

Models of care for early-stage breast cancer in Canada

There is growing evidence that follow-up for patients with early breast cancer (ebc) can be effectively carried out by the primary health care provider if a plan is in place. Here, we present data from a recent survey conducted in Ontario indicating that a shared-care model could work if communication between all health professionals involved in the care of ebc patients were to be improved. Patients and primary care providers benefit when the specialist provides written information about what their roles are and what to expect. Primary care providers need to have easy access to the specialist to discuss areas of concern. Patients also need to share responsibility for their care, ensuring that they attend follow-up visits on a regular basis and that they discuss areas of concern with their primary health care provider. A shared-care model has the potential to provide the best care for the least cost to the health system.

Chemotherapy for squamous cell carcinoma of the penis: An 8-year, single-institution experience

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Background: Penile cancer is a rare malignancy affecting approximately 400 men per year in the United Kingdom. There are relatively limited data regarding the role of chemotherapy, although it may be considered in the adjuvant setting for high-risk disease and for palliation of metastatic disease.

Methods: Patients treated with chemotherapy between June 2002 and March 2010 were identified from our prospectively maintained institutional database. Regimens were recorded and toxicity documented according to the Common Toxicity Criteria version 4.0. Response was assessed using Response Evaluation Criteria in Solid Tumors (RECIST) version 1.0 until 2009 and then version 1.1.

Results: Twenty patients received chemotherapy either for adjuvant treatment (n=6) or for metastatic disease (n=14). Median age was 59 (range 33-80). Different regimens were used over the time period. In the adjuvant setting 4-6 cycles of chemotherapy were planned and all patients received cisplatin in combination with 5-FU or capecitabine. Five (83%) completed planned treatment with no grade 3 or 4 toxicities. One patient stopped after 2 cycles due to deteriorating renal function. Patients remained disease free at up to 22 months follow-up. In the metastatic setting, 10 patients received cisplatin and capecitabine, 1 cisplatin and 5-FU and 1 carboplatin and capecitabine. Of these 12 patients, 2 (17%) had partial response as their best response, 4 (33%) had stable disease (SD) and 6 (50%) had progressive disease (PD). Three patients (25%) experienced pulmonary embolism, 1 of whom died. Two (17%) developed grade 3 neutropenia. One patient received carboplatin, methotrexate and bleomycin with PD after 3 cycles and developed grade 3 neutropenia, stomatitis, and diarrhea. One patient received 3 cycles of paclitaxel, ifosfamide, and cisplatin with SD and no grade 3 or 4 toxicities.

Conclusions: Combination chemotherapy can be delivered with acceptable toxicity in the adjuvant setting. In the metastatic setting response rates were disappointing and treatments were associated with greater toxicity. New treatments are urgently required to improve outcomes in this difficult malignancy.

[Table: see text]

Use of genetic instability to predict biochemical recurrence in intermediate-risk prostate cancer

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Background: Biomarkers of local and systemic recurrence are needed to individualize patient risk categories and better define treatment. We hypothesized that genomic instability, as measured by percent genome alteration (PGA), can predict for biochemical failure in intermediate- risk prostate cancer.

Methods: High-resolution array comparative genomic hybridization (arrayCGH) was used to identify PGA in frozen biopsies from 120 intermediate-risk prostate cancer patients. Our cohort included 39 T1c tumors, 78 T2 tumors and 2 T3 tumors. The Gleason score was 6 in 32 tumors, 7 in 82 tumors and 8–9 in 6 tumors. PSA ranged from 2.1–33 (median 8.0). Patients were treated with intensity-modulated radiotherapy (IMRT) with doses of 75.6–79.8 Gy in 1.8–2Gy fractions, or 60–66 Gy in 3 Gy fractions.. Twenty-five percent of patients also received neoadjuvant-concurrent bicalutamide (150mg po od). Biochemical failure, defined by Phoenix criteria or the initiation of salvage therapy, was observed in 35 patients after median follow-up of 5.4 years (range 0.9–8.8).

Results: Array CGH showed variable PGA ranging from <1% to 35% (median 6.7%). PSA and the use of hormonal therapy independently influenced biochemical relapse, and formed a baseline clinical model to which PGA was added. PGA was found to be a strong predictor of biochemical relapse (p<0.0001) independent of the clinical prognostic factors (pre-treatment PSA, Gleason score and T-category). PGA was also found to be associated with unique tumour suppressor and oncogene gene loci clusters involved in genetic stability (e.g. loss of PTEN, p53, RB, NKX3.1, ATM, PARP-1 and gain of c-MYC; validated by in situ FISH).

Conclusions: This is the first report to show genetic instability can independently predict for biochemical recurrence in intermediate-risk prostate cancer. Current studies are associating specific gene loci regions with clinical outcome. Our results could provide a way forward for individualized medicine for non-indolent prostate cancer based on initial daignostic biopsy material. Supported by Prostate Cancer Canada, The Terry Fox Foundation and the Canadian Cancer Society.

No significant financial relationships to disclose.

Genetic polymorphisms of Chinese patients with ischemic stroke and concurrent stenoses of extracranial and intracranial vessels

The etiology of concurrent stenoses of extracranial and intracranial vessels in patients with ischemic stroke is poorly understood, but hereditary factors are believed to be important. We aimed to determine whether genetic polymorphisms affecting homocysteine and lipid metabolism are associated with concurrent stenoses. The genotypes of 191 Han Chinese patients with acute ischemic stroke, of whom 47 (25%) had concurrent stenoses, and 167 healthy control patients in Hong Kong were examined for the following polymorphisms: paraoxonase 1 (PON1) Q192R, methylenetetrahydrofolate reductase (MTHFR) A222V, glutamate-cysteine ligase catalytic-subunit (GCLC)-129C>T, and oxidized low-density lipoprotein receptor (OLR) 3' untranslated region C>T (rs1050283). The genotype distributions of PON1 Q192R and MTHFR A222V, which affect lipid and homocysteine metabolism, differed significantly between patients with stroke and healthy controls. The presence of at least one R allele in PON1 Q192R and a TT allele in OLR rs1050283 were associated with concurrent stenoses. We also identified a possible association between the presence of at least one V allele in MTHFR A222V and concurrent stenoses. This study shows that genetic polymorphisms affecting homocysteine and lipid metabolism are possible risk factors for stroke and concurrent stenoses.

In a randomized, double-blinded, placebo-controlled trial, the single oral dose typhoid vaccine, M01ZH09, is safe and immunogenic at doses up to 1.7 x 10(10) colony-forming units

M01ZH09, S. Typhi (Ty2 Delta aroC Delta ssaV) ZH9, is a single oral dose typhoid vaccine with independently attenuating deletions. A phase II randomized, double-blind, placebo-controlled, dose-escalating trial evaluated the safety and immunogenicity of M01ZH09 to 1.7 x 10(10) colony-forming units (CFU). 187 Healthy adults received vaccine or placebo in four cohorts. Serologic responses and IgA ELISPOT were measured. At all doses, the vaccine was well tolerated and without bacteremias. One subject had a transient low-grade fever. 62.2-86.1% of subjects seroconverted S. Typhi-specific LPS IgG and 83.3-97.4% IgA; 92.1% had a positive S. Typhi LPS ELISPOT. M01ZH09 is safe and immunogenic up to 1.7 x 10(10)CFU. Efficacy testing of this single-dose oral typhoid vaccine is needed.

Safety of adjuvant endocrine therapies in hormone receptor-positive early breast cancer

Postmenopausal patients with hormone-sensitive early breast cancer are typically treated with adjuvant endocrine therapy, which significantly reduces the risk of recurrence. Because treatment is of a long duration, side effects from adjuvant therapy can be problematic. The aromatase inhibitors (AIS) are replacing tamoxifen as first-line treatment agents for early breast cancer. Here, we present the side-effect data associated with AIS in relation to bone, gynecologic, and cardiovascular health and to arthralgia and myalgia. Although AIS have been shown to decrease bone density, increase arthralgia, and affect vaginal health, these adverse events are usually manageable, and several strategies can be followed to improve quality of life in women on AI treatment. To optimize adherence to therapy. It is important that these issues are addressed so that women can benefit from treatment.

Use of magnetic resonance angiography to predict long-term outcomes of ischemic stroke patients with concurrent stenoses in Hong Kong

PURPOSE

To determine the long-term outcome of ischemic stroke patients with concurrent intracranial and extracranial atherosclerosis using magnetic resonance angiography.

METHODS

A prospective cohort of patients in Hong Kong with acute ischemic stroke was studied with magnetic resonance angiography of the brain and carotid duplex. All patients were followed up regularly for the development of recurrent stroke, cardiac events, or death.

RESULTS

Totally 343 patients with acute ischemic stroke were included, of whom 104 (30%) had concurrent intracranial and extracranial lesions. The follow-up period was up to 76 months (mean 44.5 months). Overall, 55 patients (15.5%) died of any cause and 91 patients (26.5%) suffered a further nonfatal vascular event. The overall 5-year cumulative rates of mortality, restroke and poor outcomes (combined death and further vascular events) were 18, 27 and 37%, respectively. In patients with concurrent lesions, these rates were 31, 41 and 51%, respectively. The corresponding rates were 13, 22 and 31% in patients without concurrent lesions. The risks were highest in the first year after stroke. More deaths (log rank, 16.3; p = 0.0001), restrokes (log rank, 9.71; p = 0.002) and poor outcomes (log rank, 13.87; p = 0.0001) were found among patients with concurrent lesions. The presence of concurrent vascular lesions, advanced age, smoking, hyperlipidemia and previous history of stroke were independent predictors of poor outcomes.

CONCLUSIONS

The long-term prognosis of ischemic stroke patients with concurrent atherosclerosis of intracranial and extracranial vessels is poor. They are at high risk of further vascular events or death.