Publications by authors named "Antony R Lafferty"

14 Publications

  • Page 1 of 1

Associations Between Hyperphagia, Symptoms of Sleep Breathing Disorder, Behaviour Difficulties and Caregiver Well-Being in Prader-Willi Syndrome: A Preliminary Study.

J Autism Dev Disord 2021 Sep 8. Epub 2021 Sep 8.

Telethon Kids Institute, The Centre for Child Health Research, The University of Western Australia, PO Box 855, West Perth, WA, 6872, Australia.

Prader-Willi syndrome (PWS) is a rare genetic disorder characterised by neurodevelopmental delays, hyperphagia, difficulties with social communication and challenging behaviours. Individuals require intensive supervision from caregivers which may negatively affect caregiver quality of life. This study used data collected in the Australasian PWS Registry (n = 50, mean age 11.2 years) to evaluate associations between child behaviours and caregiver mental well-being. Symptoms of sleep-related breathing disorder, child depression and social difficulties were associated with poorer caregiver mental and physical well-being. Growth hormone therapy use was associated with better caregiver mental and physical well-being. Optimising management of problematic behaviours and sleep disturbances have the potential to support caregivers who are the most vital network of support for individuals affected by PWS.
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September 2021

Sleep-disordered breathing in Australian children with Prader-Willi syndrome following initiation of growth hormone therapy.

J Paediatr Child Health 2021 Aug 16. Epub 2021 Aug 16.

Telethon Kids Institute, The Centre for Child Health Research, The University of Western Australia, Perth, Western Australia, Australia.

Aim: In children with Prader-Willi syndrome (PWS), growth hormone (GH) improves height and body composition; however, may be associated with worsening sleep-disordered breathing (SDB). Some studies have reported less SDB after GH initiation, but follow-up with polysomnography is still advised in most clinical guidelines.

Methods: This retrospective, multicentre study, included children with PWS treated with GH at seven PWS treatment centres in Australia over the last 18 years. A paired analysis comparing polysomnographic measures of central and obstructive SDB in the same child, before and after GH initiation was performed with Wilcoxon signed-rank test. The proportion of children who developed moderate/severe obstructive sleep apnoea (OSA) was calculated with their binomial confidence intervals.

Results: We included 112 patients with available paired data. The median age at start of GH was 1.9 years (range 0.1-13.5 years). Median obstructive apnoea hypopnoea index (AHI) at baseline was 0.43/h (range 0-32.9); 35% had an obstructive AHI above 1.0/h. Follow-up polysomnography within 2 years after the start of GH was available in 94 children who did not receive OSA treatment. After GH initiation, there was no change in central AHI. The median obstructive AHI did not increase significantly (P = 0.13), but 12 children (13%, CI 7-21%) developed moderate/severe OSA, with clinical management implications.

Conclusions: Our findings of a worsening of OSA severity in 13% of children with PWS support current advice to perform polysomnography after GH initiation. Early identification of worsening OSA may prevent severe sequelae in a subgroup of children.
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August 2021

Global consensus on nutritional rickets: Implications for Australia.

J Paediatr Child Health 2020 06;56(6):841-846

Institute of Endocrinology and Diabetes, Children's Hospital Westmead, Sydney, New South Wales, Australia.

In 2016, a global consensus on the prevention, diagnosis and management of nutritional rickets was published. The bone and mineral working group of the Australasian Paediatric Endocrine Group provides a summary and highlights differences to previous Australian and New Zealand (ANZ) guidelines on vitamin D deficiency and their implications for clinicians. Key points are: (i) The International Consensus document is focused on nutritional rickets, whereas the ANZ guidelines were focused on vitamin D deficiency. (ii) Definitions for the interpretation of 25-hydroxy vitamin D (25OHD) levels do not differ between statements. (iii) The global consensus recommends that routine 25OHD screening should not be performed in healthy children and recommendations for vitamin D supplementation are not based solely on 25OHD levels. The Australasian Paediatric Endocrine Group bone and mineral working group supports that screening for vitamin D deficiency should be restricted to populations at risk. (iv) Recommendations from the global consensus for vitamin D dosages for the therapy of nutritional rickets (diagnosed based on history, physical examination, biochemical testing and a confirmation by X-rays) are higher than in ANZ publications. (v) The global consensus recommends the implementation of public health strategies such as universal supplementation with vitamin D from birth to 1 year of age and food fortification. We conclude that updated global recommendations for therapy of nutritional rickets complement previously published position statements for Australia and New Zealand. Screening, management and the implementation of public health strategies need to be further explored for Australia.
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June 2020

Heparanase and Type 1 Diabetes.

Adv Exp Med Biol 2020 ;1221:607-630

ACRF Department of Cancer Biology and Therapeutics, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia.

Type 1 diabetes (T1D) results from autoimmune destruction of insulin-producing beta cells in pancreatic islets. The degradation of the glycosaminoglycan heparan sulfate (HS) by the endo-β-D-glycosidase heparanase plays a critical role in multiple stages of the disease process. Heparanase aids (i) migration of inflammatory leukocytes from the vasculature to the islets, (ii) intra-islet invasion by insulitis leukocytes, and (iii) selective destruction of beta cells. These disease stages are marked by the solubilization of HS in the subendothelial basement membrane (BM), HS breakdown in the peri-islet BM, and the degradation of HS inside beta cells, respectively. Significantly, healthy islet beta cells are enriched in highly sulfated HS which is essential for their viability, protection from damage by reactive oxygen species (ROS), beta cell function and differentiation. Consequently, mouse and human beta cells but not glucagon-producing alpha cells (which contain less-sulfated HS) are exquisitely vulnerable to heparanase-mediated damage. In vitro, the death of HS-depleted mouse and human beta cells can be prevented by HS replacement using highly sulfated HS mimetics or analogues. T1D progression in NOD mice and recent-onset T1D in humans correlate with increased expression of heparanase by circulating leukocytes of myeloid origin and heparanase-expressing insulitis leukocytes. Treatment of NOD mice with the heparanase inhibitor and HS replacer, PI-88, significantly reduced T1D incidence by 50%, impaired the development of insulitis and preserved beta cell HS. These outcomes identified heparanase as a novel destructive tool in T1D, distinct from the conventional cytotoxic and apoptosis-inducing mechanisms of autoreactive T cells. In contrast to exogenous catalytically active heparanase, endogenous heparanase may function in HS homeostasis, gene expression and insulin secretion in normal beta cells and immune gene expression in leukocytes. In established diabetes, the interplay between hyperglycemia, local inflammatory cells (e.g. macrophages) and heparanase contributes to secondary micro- and macro-vascular disease. We have identified dual activity heparanase inhibitors/HS replacers as a novel class of therapeutic for preventing T1D progression and potentially for mitigating secondary vascular disease that develops with long-term T1D.
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July 2020

Requirements for improving health and well-being of children with Prader-Willi syndrome and their families.

J Paediatr Child Health 2019 Sep 30;55(9):1029-1037. Epub 2019 Jun 30.

Telethon Kids Institute, Centre for Child Health Research, University of Western Australia, Perth, Western Australia, Australia.

Prader-Willi syndrome (PWS) is a rare genetic condition with multi-system involvement. The literature was reviewed to describe neurodevelopment and the behavioural phenotype, endocrine and metabolic disorders and respiratory and sleep functioning. Implications for child and family quality of life were explored. Challenging behaviours contribute to poorer well-being and quality of life for both the child and caregiver. Recent evidence indicates healthy outcomes of weight and height can be achieved with growth hormone therapy and dietary restriction and should be the current target for all individuals with PWS. Gaps in the literature included therapies to manage challenging behaviours, as well as understanding the effects of growth hormone on respiratory and sleep function. New knowledge regarding the transition of children and families from schooling and paediatric health services to employment, accommodation and adult health services is also needed. Developing a national population-based registry could address these knowledge gaps and inform advocacy for support services that improve the well-being of individuals with PWS and their families.
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September 2019

Functional characterization of novel NR5A1 variants reveals multiple complex roles in disorders of sex development.

Hum Mutat 2018 01 2;39(1):124-139. Epub 2017 Nov 2.

Murdoch Children's Research Institute, Melbourne, Australia.

Variants in the NR5A1 gene encoding SF1 have been described in a diverse spectrum of disorders of sex development (DSD). Recently, we reported the use of a targeted gene panel for DSD where we identified 15 individuals with a variant in NR5A1, nine of which are novel. Here, we examine the functional effect of these changes in relation to the patient phenotype. All novel variants tested had reduced trans-activational activity, while several had altered protein level, localization, or conformation. In addition, we found evidence of new roles for SF1 protein domains including a region within the ligand binding domain that appears to contribute to SF1 regulation of Müllerian development. There was little correlation between the severity of the phenotype and the nature of the NR5A1 variant. We report two familial cases of NR5A1 deficiency with evidence of variable expressivity; we also report on individuals with oligogenic inheritance. Finally, we found that the nature of the NR5A1 variant does not inform patient outcomes (including pubertal androgenization and malignancy risk). This study adds nine novel pathogenic NR5A1 variants to the pool of diagnostic variants. It highlights a greater need for understanding the complexity of SF1 function and the additional factors that contribute.
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January 2018

Hashimoto's encephalopathy and anti-MOG antibody encephalitis: 50 years after Lord Brain's description.

Eur J Paediatr Neurol 2017 Nov 10;21(6):898-901. Epub 2017 Jun 10.

Department of Paediatric Neurology, Sydney Children's Hospital, Randwick, Australia; School of Women's and Children's Health, UNSW, Sydney, Australia. Electronic address:

Purpose: To consider the role of anti-MOG Abs associated encephalitis in Hashimoto's Encephalitis (HE).

Results: A 10 year old girl with pre-existing Hashimoto's thyroiditis presented with dysarthria, ataxia and lethargy whilst euthyroid. Brain MRI showed multifocal T2 and FLAIR hyperintense lesions. She responded promptly to treatment with corticosteroids. Her clinical scenario was comparable to a sizeable minority of patients diagnosed with HE in the literature, who have similar brain MRIs. Serum was positive for anti-myelin oligodendrocyte glycoprotein (MOG) Ab, implicating this antibody-mediated process in this patient's illness.

Conclusion: We hypothesize that anti-MOG Ab associated demyelination may underlie a subset of patients with HE.
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November 2017

Disorders of sex development: insights from targeted gene sequencing of a large international patient cohort.

Genome Biol 2016 11 29;17(1):243. Epub 2016 Nov 29.

Department of Medical Genetics, Sydney Children's Hospital, Randwick, NSW, Australia.

Background: Disorders of sex development (DSD) are congenital conditions in which chromosomal, gonadal, or phenotypic sex is atypical. Clinical management of DSD is often difficult and currently only 13% of patients receive an accurate clinical genetic diagnosis. To address this we have developed a massively parallel sequencing targeted DSD gene panel which allows us to sequence all 64 known diagnostic DSD genes and candidate genes simultaneously.

Results: We analyzed DNA from the largest reported international cohort of patients with DSD (278 patients with 46,XY DSD and 48 with 46,XX DSD). Our targeted gene panel compares favorably with other sequencing platforms. We found a total of 28 diagnostic genes that are implicated in DSD, highlighting the genetic spectrum of this disorder. Sequencing revealed 93 previously unreported DSD gene variants. Overall, we identified a likely genetic diagnosis in 43% of patients with 46,XY DSD. In patients with 46,XY disorders of androgen synthesis and action the genetic diagnosis rate reached 60%. Surprisingly, little difference in diagnostic rate was observed between singletons and trios. In many cases our findings are informative as to the likely cause of the DSD, which will facilitate clinical management.

Conclusions: Our massively parallel sequencing targeted DSD gene panel represents an economical means of improving the genetic diagnostic capability for patients affected by DSD. Implementation of this panel in a large cohort of patients has expanded our understanding of the underlying genetic etiology of DSD. The inclusion of research candidate genes also provides an invaluable resource for future identification of novel genes.
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November 2016

Hereditary pituitary hyperplasia with infantile gigantism.

J Clin Endocrinol Metab 2011 Dec 5;96(12):E2078-87. Epub 2011 Oct 5.

Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA.

Context: We report hereditary pituitary hyperplasia.

Objective: The objective of the study was to describe the results of the clinical and laboratory analysis of this rare instance of hereditary pituitary hyperplasia.

Design: The study is a retrospective analysis of three cases from one family.

Setting: The study was conducted at the National Institutes of Health, a tertiary referral center.

Patients: A mother and both her sons had very early-onset gigantism associated with high levels of serum GH and prolactin.

Interventions: The condition was treated by total hypophysectomy.

Main Outcome Measure(s): We performed clinical, pathological, and molecular evaluations, including evaluation basal and provocative endocrine testing, neuroradiological assessment, and assessment of the pituitary tissue by microscopic evaluation, immunohistochemistry, and electron microscopy.

Results: All three family members had very early onset of gigantism associated with abnormally high serum levels of GH and prolactin. Serum GHRH levels were not elevated in either of the boys. The clinical, radiographic, surgical, and histological findings indicated mammosomatotroph hyperplasia. The pituitary gland of both boys revealed diffuse mammosomatotroph hyperplasia of the entire pituitary gland without evidence of adenoma. Prolactin and GH were secreted by the same cells within the same secretory granules. Western blot and immunohistochemistry demonstrated expression of GHRH in clusters of cells distributed throughout the hyperplastic pituitary of both boys.

Conclusions: This hereditary condition seems to be a result of embryonic pituitary maldevelopment with retention and expansion of the mammosomatotrophs. The findings suggest that it is caused by paracrine or autocrine pituitary GHRH secretion during pituitary development.
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December 2011

Increased detection of cystic-fibrosis-related diabetes in Australia.

Arch Dis Child 2011 Sep 8;96(9):823-6. Epub 2011 Jun 8.

Institute of Endocrinology and Diabetes, Children's Hospital at Westmead, Locked Bag 4001, Westmead, 2145 NSW, Australia

Objectives: To estimate the incidence of cystic-fibrosis-related diabetes (CFRD) in youth from New South Wales (NSW) and the Australian Capital Territory (ACT), Australia and to examine demographic/clinical features at diagnosis.

Methods: Incident cases of CFRD in young people aged ≤ 18 years diagnosed during 2000 to 2008 were identified from four paediatric cystic fibrosis (CF) clinics and the NSW/ACT Australasian Paediatric Endocrine Group Diabetes Register.

Results: CFRD was diagnosed in 41 cases (59% girls). The estimated mean annual incidence of CFRD among patients with CF was 9.4 per 1000 person years (95% CI 6.8 to 12.8). Incidence increased from 2.0 per 1000 person years in 2000 to 22.1 per 1000 in 2008 (incidence RR 1.3, 95% CI 1.1 to 1.4). Haemoglobin A1c (HbA1c) was abnormal in the majority at diagnosis: median HbA1c was 6.9% (6.2-8.1%). More cases were diagnosed using an oral glucose tolerance test in 2007-2008 compared with previous years (61% vs 6%, p<0.001).

Conclusions: CFRD is increasingly recognised and now affects approximately one in five young people with CF. The rising incidence is likely to be due to increased detection, resulting from greater awareness and changes in screening practices. Widespread uptake of consensus guidelines for screening will ensure accurate case detection, but will also impact on patient care and resource allocation.
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September 2011

Salmonella Rubislaw gastroenteritis linked to a pet lizard.

Med J Aust 2010 Jul;193(1):54-5

Communicable Disease Control, ACT Health Protection Service, Canberra, ACT.

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July 2010

Establishment of pediatric reference intervals on a large cohort of healthy children.

Clin Chim Acta 2010 Oct 22;411(19-20):1421-7. Epub 2010 Jun 22.

ACT Pathology, The Canberra Hospital, Canberra, Australia.

Background: Reference intervals are essential in assessing the significance of laboratory results. There have been limited studies generating reference intervals from pediatric populations. We have studied a large cohort of healthy children on 3 separate occasions at 2yearly intervals.

Methods: 852 healthy 8year old children were enrolled in a community-based multidisciplinary longitudinal study investigating how early physical activity contributes to health. The same children came back for reassessment at ages 10 and 12years. Blood samples were analyzed for a total of 37 different chemistries, immunoassays or derived values.

Results: Reference intervals were derived for all the analytes for males and females separately.

Conclusion: Whilst our results are largely in agreement with previously published work, we have shown that for a number of analytes, previously published work is distorted by subclinical disease.
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October 2010

Contrasting longitudinal and cross-sectional relationships between insulin resistance and percentage of body fat, fitness, and physical activity in children-the LOOK study.

Pediatr Diabetes 2009 Dec 30;10(8):500-7. Epub 2009 Apr 30.

Medical School, Australian National University and Commonwealth Institute, Canberra, ACT, Australia.

Background: Knowledge of individual changes in insulin resistance (IR) and longitudinal relationships of IR with lifestyle-associated factors are of important practical significance, but little longitudinal data exist in asymptomatic children. We aimed to determine (a) changes in the homeostatic model of insulin resistance (HOMA-IR) over a 2-yr period and (b) comparisons of longitudinal and cross-sectional relationships between HOMA-IR and lifestyle-related risk factors.

Methods: Our subjects, 241 boys and 257 girls, were assessed at age 8.1 yr (SD 0.35) and again 2 yr later for fasting blood glucose and insulin, dual X-ray absorptiometry-assessed percentage of body fat (%BF), pedometer-assessed physical activity (PA), and cardio-respiratory fitness (CRF) by multistage running test.

Results: HOMA-IR was initially 9% greater in girls than boys and 27% greater 2 yr later. There was no evidence of longitudinal relationships between HOMA-IR and %BF in boys or girls, despite significant cross-sectional relationships (p < 0.001). In boys, there was evidence of a longitudinal relationship between HOMA-IR and both PA (p < 0.001) and CRF (p = 0.05). In girls, we found a cross-sectional relationship between HOMA-IR and CRF (p < 0.001).

Conclusions: HOMA-IR increases between 8 and 10 yr of age and to a greater extent in girls. Longitudinal, unlike cross-sectional, relationships do not support the premise that body fat has any impact on HOMA-IR during this period or that PA or CRF changes affect HOMA-IR in girls. These data draw attention to difficulties in interpreting observational studies in young children.
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December 2009

Discordance of international adiposity classifications in Australian boys and girls - the LOOK study.

Ann Hum Biol 2008 May-Jun;35(3):334-41

Faculty of Medicine, Australian National University, Canberra, ACT, Australia.

Background: Various charts based on body mass index (BMI) and per cent body fat (%BF) are used to classify childhood body composition but outcomes may vary.

Aim: The study investigated variation in incidences of childhood obesity as depicted by four classification charts.

Subjects And Methods: BMI and DXA-derived %BF were assessed in 741 children. Incidences of overweight and obesity were compared between two BMI charts and two bioelectrical impedance (BIA)-based %BF charts.

Results: The International Obesity Task Force (IOTF)-adopted BMI chart designated 21%, 6% (boys), and 26%, 9% (girls) as overweight and obese, respectively. Corresponding figures using the USA CDC BMI chart were 27%, 11% (boys) and 27%, 12% (girls). Using a USA-derived %BF chart incidences were 17%, 2% (boys) and 21%, 8% (girls) and using a UK-derived %BF chart 51%, 24% (boys) and 53%, 36% (girls). Sensitivity of BMI varied according to the %BF reference chart.

Conclusions: In contrast to the BMI-based charts, there were considerable variations in depicted incidences of obesity between the %BF-based charts. These discordances were considered to result from previously reported variation within and between BIA and DXA %BF assessments underlying the charts. The present study highlights the need for valid, reliable, unchanging BIA and DXA procedures.
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August 2008