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Articles
by
S. Ellard |
Total Records (
8 ) for
S. Ellard |
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A. Wirsing
,
K. A. Johnstone
,
L. W. Harries
,
S. Ellard
,
G. U. Ryffel
,
J. Stanik
,
D. Gasperikova
,
I. Klimes
and
R. Murphy
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Aims Mutations in HNF4A cause a form of monogenic β-cell
diabetes. We aimed to identify mutations in the pancreas-specific P2 promoter
of HNF4A in families with suspected HNF4A diabetes and to show that
they impaired the function of the promoter in vitro.
Methods We screened families with a clinical suspicion of HNF4A
monogenic β-cell diabetes for mutations in the HNF4A P2 promoter.
We investigated the function of the previously reported HNF4A P2 promoter
mutation −192C>G linked to late-onset diabetes in several families, along
with two new segregating mutations, in vitro using a modified luciferase
reporter assay system with enhanced sensitivity.
Results We identified two novel HNF4A P2 promoter mutations that
co-segregate with diabetes in two families, −136A>G and −169C>T.
Both families displayed phenotypes typical of HNF4A monogenic β-cell
diabetes, including at least two affected generations, good response to sulphonylurea
treatment and increased birthweight and/or neonatal hypoglycaemia. We show that
both of these novel mutations and −192C>G impair the function of the
promoter in transient transfection assays.
Conclusions Two novel mutations identified here and the previously identified
late-onset diabetes mutation, −192C>G, impair the function of the HNF4A
P2 promoter in vitro. |
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J. Grulich-Henn
,
V. Wagner
,
A. Thon
,
E. Schober
,
W. Marg
,
T. M. Kapellen
,
H. Haberland
,
K. Raile
,
S. Ellard
,
S. E. Flanagan
,
A. T. Hattersley
and
R. W. Holl
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Aims The aim of this study was to elucidate the entities and the frequency
of neonatal diabetes mellitus (NDM) in a large representative database for paediatric
diabetes patients in Germany and Austria.
Methods Based on the continuous diabetes data acquisition system for
prospective surveillance (DPV), which includes 51 587 patients with onset
of diabetes before the age of 18 years from 299 centres in Germany and Austria,
we searched for patients with onset of diabetes mellitus in the first 6 months
of life.
Results Ninety patients were identified, comprising 0.17% of all paediatric
cases in the DPV registry. This represented an incidence of approximately one
case in 89 000 live births in Germany. A monogenic basis for NDM was established
in 30 subjects (seven UPD6, 10 KCNJ11, seven ABCC8, two FOXP3,
two PDX1, one INS, one EIF2AK3). Pancreatic hypoplasia or
agenesis was reported in 10 patients and seven subjects were classified as having
Type 1 diabetes by their centres. Transient neonatal diabetes (TNDM) accounted
for approximately 10% of all cases with NDM. No aetiology was defined in 41 subjects,
which may reflect incomplete genetic testing or novel genetic aetiologies.
Conclusion Based on a large database, we identified a higher rate of
NDM in Germany than has been reported previously. Full molecular genetic testing
should be performed in all patients diagnosed before 6 months of age. |
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A. M. Steele
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B. M. Shields
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M. Shepherd
,
S. Ellard
,
A. T. Hattersley
and
E. R. Pearson
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Aims: To investigate all-cause and cardiovascular mortality in subjects with diabetes caused by a mutation in the hepatocyte nuclear factor 1α gene (HNF1A). Methods: We identified 39 British families with HNF1A mutations. Consenting individuals were asked details of age and cause of death of parents and siblings. Copies of death certificates were requested from the family or were obtained via the Offices for National Statistics.
Results: Data were collated on 241 control subjects and 153 mutation
carriers. Of those who died, 66% of mutation carriers died from a cardiovascular-related
illness compared with 43% of control subjects (P=0.02). Family
members with HNF1A mutations died at a younger age than familial control
subjects [all-cause hazard ratio, adjusting for sex and smoking status: 1.9 (95%
confidence interval 1.2, 2.9, P=0.006; cardiovascular hazard
ratio: 2.3, confidence interval 1.3, 4.2, P=0.006)].Conclusions:
We have shown that individuals known to have diabetes caused by a mutation in
the HNF1A gene have an increased risk of cardiovascular mortality compared
with their unaffected family members. As with other forms of diabetes, consideration
should be given to early statin therapy despite a seemingly protective lipid profile. |
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G. Spyer
,
K. M. Macleod
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M. Shepherd
,
S. Ellard
and
A. T. Hattersley
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Aim To assess determinants of fetal growth in the offspring of pregnant women with hyperglycaemia due to a heterozygous glucokinase (GCK) gene mutation.Methods Details of gestational age at delivery, fetal birth weight and maternal antenatal treatment were collected from patients and retrospective case note review of 82 offspring born to 42 women with GCK gene mutations and 31 offspring born to 13 unaffected normoglycaemic women with an affected partner. Fetal genotype was determined using direct sequencing from either a mouth swab or a blood sample. Results In mothers with GCK mutations, non-mutation-carrying offspring were heavier than mutation-carrying offspring (corrected birth weight 3.9 ± 0.6 vs. 3.2 ± 0.8 kg; P < 0.001) and more likely to be macrosomic (> 4.0 kg; 39% vs. 7%, P = 0.001). There was no difference in corrected birth weight between offspring of insulin- and diet-treated women (3.7 ± 0.7 vs. 3.8 ± 0.6 kg; P = 0.1), although insulin-treated mothers delivered earlier (37.5 ± 1.7 vs. 38.9 ± 2.3 weeks; P < 0.001) due to increased obstetric intervention. Conclusions Offspring of women with GCK mutations are at increased risk of macrosomia and its obstetric consequences. Fetal birth weight is predominantly altered by fetal genotype and not treatment of maternal hyperglycaemia with insulin. This probably reflects the large effect of a fetal GCK mutation on fetal insulin secretion and the difficulty in reducing the regulated maternal glycaemia caused by a glucose sensing defect in people with GCK mutations. |
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M. Shepherd
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B. Shields
,
S. Ellard
,
O. Rubio-Cabezas
and
A. T. Hattersley
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Background and aims Hepatocyte nuclear factor-1 alpha (HNF1A) gene mutations are the commonest cause of monogenic diabetes, but patients are often misdiagnosed as having Type 1 diabetes and started on insulin treatment. Patients with HNF1A diabetes are particularly sensitive to the glucose-lowering effect of sulphonylureas, which are the pharmacological treatment of choice. We aimed to assess if patients do change from insulin to sulphonylurea treatment when HNF1A diabetes is confirmed and the impact of this treatment change on long-term glycaemic control.Methods We investigated the clinical course of 43 patients who were insulin treated from diagnosis for a median 4 years (range 1-14) before an HNF1A gene mutation was identified. Results Thirty-four patients (79%) stopped insulin following genetic testing and transferred to sulphonylureas. Twenty-four of them (71%) remained off insulin at a median 39 months (range 17-90) post-transfer. The 10 patients who recommenced insulin had a trend towards a longer duration of diabetes (18 vs. 7 years, P = 0.066) compared with those remaining on tablets. The median glycated haemoglobin (HbA1c) was good (6.9%; interquartile range 6.3-8.0%) in the patients who remained off insulin and 19/24 patients (79%) achieved HbA1c < 7.5% or improved their pre-genetic diagnosis HbA1c by > 1.0%. Transfer off insulin was not attempted in eight patients: one of these was planning pregnancy and two chose to remain on insulin. Conclusion In this observational study we found that a molecular genetic diagnosis of HNF1A diabetes does alter treatment in clinical practice, with 79% attempting transfer to sulphonylureas. Transfer to sulphonylureas was successful in the majority of patients without deterioration in glycaemic control. |
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E. L. Edghill
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A. Khamis
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M. N. Weedon
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M. Walker
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G. A. Hitman
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M. I. McCarthy
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K. R. Owen
,
S. Ellard
,
A. T Hattersley
and
T. M. Frayling
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Aim Genome-wide association studies have identified > 30 common variants associated with Type 2 diabetes (> 5% minor allele frequency). These variants have small effects on individual risk and do not account for a large proportion of the heritable component of the disease. Monogenic forms of diabetes are caused by mutations that occur in < 1:2000 individuals and follow strict patterns of inheritance. In contrast, the role of low frequency genetic variants (minor allele frequency 0.1-5%) in Type 2 diabetes is not known. The aim of this study was to assess the role of low frequency PDX1 (also called IPF1) variants in Type 2 diabetes.Methods We sequenced the coding and flanking intronic regions of PDX1 in 910 patients with Type 2 diabetes and 878 control subjects. Results We identified a total of 26 variants that occurred in 5.3% of individuals, 14 of which occurred once. Only D76N occurred in > 1%. We found no difference in carrier frequency between patients (5.7%) and control subjects (5.0%) (P = 0.46). There were also no differences between patients and control subjects when analyses were limited to subsets of variants. The strongest subset were those variants in the DNA binding domain where all five variants identified were only found in patients (P = 0.06). Conclusion Approximately 5% of UK individuals carry a PDX1 variant, but there is no evidence that these variants, either individually or cumulatively, predispose to Type 2 diabetes. Further studies will need to consider strategies to assess the role of multiple variants that occur in < 1 in 1000 individuals. |
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E. L. Edghill
,
K. Stals
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R. A. Oram
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M. H. Shepherd
,
A. T. Hattersley
and
S. Ellard
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Aims Hepatocyte nuclear factor 1β (HNF1B) mutations cause a syndrome of renal cysts and diabetes, with whole gene deletions accounting for approximately 50% of cases. The severity of the renal phenotype is variable, from enlarged cystic kidneys incompatible with life to normal renal development and function. We investigated the prevalence of HNF1B deletions in patients with diabetes but no known renal disease.Methods We tested 461 patients with familial diabetes diagnosed before 45 years, including 258 probands who met clinical criteria for maturity-onset diabetes of the young (two generations affected and at least one family member diagnosed under 25 years). A fluorescent polymerase chain reaction assay was used to analyse two intragenic polymorphic HNF1B markers and identify heterozygous patients who therefore did not have whole gene deletions. Those patients homozygous for both markers were then tested for an HNF1B deletion using multiplex ligation-dependent probe amplification. Results Heterozygous HNF1B intragenic polymorphisms were identified in 337/461 subjects. Multiplex ligation-dependent probe amplification analysis showed an HNF1B gene deletion in three of the remaining 124 probands, all of whom met the criteria for maturity-onset diabetes of the young. Testing of their relatives identified three additional deletion carriers and ultrasound scanning showed renal developmental abnormalities in three of these six patients. Conclusions We estimate that HNF1B mutations account for < 1% of cases of maturity-onset diabetes of the young. Although HNF1B mutations are a rare cause of diabetes in the absence of known renal disease, a genetic diagnosis of renal cysts and diabetes syndrome is important as it raises the possibility of subclinical renal disease and the 50% risk of renal cysts and diabetes syndrome in the patient's offspring. |
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