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Current practice is to report and manage likely pathogenic/pathogenic variants in a given cancer susceptibility gene as though having equivalent penetrance, despite increasing evidence of intervariant variability in risk associations. Using existing variant interpretation approaches, largely based on full-penetrance models, variants in which reduced penetrance is suspected may be classified inconsistently and/or as variants of uncertain significance. We aimed to develop a national consensus approach for such variants within the Cancer Variant Interpretation Group UK (CanVIG-UK) multidisciplinary network.

CHN is genetically heterogeneous and its genetic basis is difficult to determine on features alone. CNTNAP1encodes CASPR, integral in the paranodal junction high molecular mass complex. Nineteen individuals with biallelic variants have been described in association with severe congenital hypomyelinating neuropathy, respiratory compromise, profound intellectual disability and death within the first year. We report 7 additional patients ascertained through exome sequencing. We identified 9 novel CNTNAP1variants in 6 families: three missense variants, four nonsense variants, one frameshift variant and one splice site variant. Significant polyhydramnios occurred in 6/7 pregnancies. Severe respiratory compromise was seen in 6/7 (tracheostomy in 5). A complex neurological phenotype was seen in all patients who had marked brain hypomyelination/demyelination and profound developmental delay. Additional neurological findings included cranial nerve compromise: orobulbar dysfunction in 5/7, facial nerve weakness in 4/7 and vocal cord paresis in 5/7. Dystonia occurred in 2/7 patients and limb contractures in 5/7. All had severe gastroesophageal reflux, and a gastrostomy was required in 5/7. In contrast to most previous reports, only one patient died in the first year of life. Protein modelling was performed for all detected CNTNAP1variants. We propose a genotype–phenotype correlation, whereby hypomorphic missense variants partially ameliorate the phenotype, prolonging survival. This study suggests that biallelic variants in CNTNAP1cause a distinct recognisable syndrome, which is not caused by other genes associated with CHN. Neonates presenting with this phenotype will benefit from early genetic definition to inform clinical management and enable essential genetic counselling for their families.

Context:GLIS3(GLI-similar 3) is a member of the GLI-similar zinc finger protein family encoding for a nuclear protein with 5 C2H2-type zinc finger domains. The protein is expressed early in embryogenesis and plays a critical role as both a repressor and activator of transcription. Human GLIS3 mutations are extremely rare.Objective:The purpose of this article was determine the phenotypic presentation of 12 patients with a variety of GLIS3mutations.Methods:GLIS3gene mutations were sought by PCR amplification and sequence analysis of exons 1 to 11. Clinical information was provided by the referring clinicians and subsequently using a questionnaire circulated to gain further information.Results:We report the first case of a patient with a compound heterozygous mutation in GLIS3who did not present with congenital hypothyroidism. All patients presented with neonatal diabetes with a range of insulin sensitivities. Thyroid disease varied among patients. Hepatic and renal disease was common with liver dysfunction ranging from hepatitis to cirrhosis; cystic dysplasia was the most common renal manifestation. We describe new presenting features in patients with GLIS3 mutations, including craniosynostosis, hiatus hernia, atrial septal defect, splenic cyst, and choanal atresia and confirm further cases with sensorineural deafness and exocrine pancreatic insufficiency.Conclusion:We report new findings within the GLIS3phenotype, further extending the spectrum of abnormalities associated with GLIS3mutations and providing novel insights into the role of GLIS3in human physiological development. All but 2 of the patients within our cohort are still alive, and we describe the first patient to live to adulthood with a GLIS3mutation, suggesting that even patients with a severe GLIS3phenotype may have a longer life expectancy than originally described.

Congenital pancreatic hypoplasia is a rare cause of neonatal diabetes. We report on a series of three patients with pancreatic agenesis and congenital heart defects. All had abdominal scan evidence of pancreatic agenesis. In addition, Patient 1 had a ventricular septal defect, patent ductus arteriosus and pulmonary artery stenosis; Patient 2 had a truncus arteriosus and Patient 3 had tetralogy of Fallot. Two of the three patients have developmental delay. All three patients were isolated cases within the family. Investigations included sequencing of GCK, ABCC8, IPF1, NEUROD1, PTF1A, HNF1B, INS, ISL1, NGN3, HHEX, G6PC2, TCF7L2, SOX4, FOXP3Patients 1 and 2, GATA4and KCNJ11genes all three patients, but no mutations were found. Genetic investigation to exclude paternal UPD 6, methylation aberrations and duplications of 6q24 was also negative in all three. 22q11 deletion was excluded in all three patients. Array CGH in Patient 1 showed a ∼250 kb, paternally inherited duplication of chromosome 12q arr cgh 12q24.33 B35:CHR12:131808577–132057649 pat, not found in the other two patients. Permanent neonatal diabetes mellitus due to pancreatic hypoplasia with congenital heart defects has been reported before and may represent a distinct condition. We discuss this rare association and review previously reported literature. © 2010 WileyLiss, Inc.

Activating mutations in the human KCNJ11gene, encoding the pore-forming subunit (Kir6.2) of the ATP-sensitive potassium (KATP) channel, are one cause of neonatal diabetes mellitus. In a few patients, KCNJ11mutations cause a triad of developmental delay, epilepsy, and neonatal diabetes (DEND syndrome). The aim of this study was to determine the clinical effects, functional cause, and sensitivity to sulfonylurea treatment of a novel KCNJ11mutation producing DEND syndrome.

AbstractThe lipodystrophies are a heterogeneous group of disorders of adipose tissue associated with insulin resistance. The sporadic form of partial lipodystrophy, characterised by fat loss from the face and upper body, is associated with complement abnormalities and mesangiocapillary glomerulonephritis type 2 (MCGN II) and the conditions are thought to have a shared autoimmune aetiology. We present the first case of the rare familial form of partial lipodystrophy, caused by a mutation in the LMNA gene, associated with MCGN II. This suggests that partial lipodystrophy of both the sporadic and familial subtypes may predispose to this condition and that the observed renal and complement abnormalities may be secondary to other factors associated with lipodystrophy.Copyright © 2004 S. Karger AG, Basel

Abstract: Mantle cell lymphoma is characterized by the presence of the t(11;14)(q13;q32) translocation that causes over-expression of the BCL-1 gene and consequent overproduction of its gene product cyclin D1. We have developed a competitive fluorescent reverse transcription polymerase chain reaction assay for the detection and semiquantitation of cyclin D1 over-expression. Using this assay a definitive ratio of the expression of cyclin D1 to cyclins D2 and D3 can be determined, provided good quality RNA is available. A single upstream primer derived from a consensus sequence found in cyclins D1, D2, and D3 was labeled at the 5′ end using a fluorescent dye. Downstream primers specific to cyclins D1 and D2 were designed and used in conjunction with a previously published D3 specific primer. The fluorescently labeled PCR products were separated by electrophoresis using an ABI 377 DNA sequencer. Fluorescence emitted from each product was used to determine the ratio of expression of cyclin D1 to D2 and D3 by assigning a dosage quotient [D1/(D2+D3)]. The mean dosage quotient recorded from samples representing 29 non-MCL patients was 0.03 (SD ± 0.03), the maximum value being 0.11. Samples from eight patients with a diagnosis of MCL generated values greater than 2. Calculation of a dosage quotient using this competitive fluorescent reverse transcription polymerase chain reaction assay allows unequivocal identification of patients with over-expression of cyclin D1, providing a new tool for the differential diagnosis of MCL.

AbstractHepatocyte nuclear factor (HNF)1α is a homeodomaincontaining transcription factor participating in the regulation of gene expression in liver, kidney, gut and pancreas of vertebrates. In humans mutations in the HNF1α gene are responsible for one form of maturity onset diabetes of the young (MODY3). To define the molecular mechanism underlying MODY3 we investigated the functional properties of seven MODY3- associated mutations representing the spectrum of different kinds of mutations affecting all functional domains of the protein. The mutations introduced into an expression vector encoding human HNF1α include inframe deletion (ΔN127), nonsense (Q7X, R171X), frameshift (P291fsinsC) and missense (R229Q, P447L, T620I) mutations. Gel retardation and reporter gene assays showed that the functional properties of these mutants differ dramatically, but none of these mutants act in a dominant negative manner. Moreover, the mRNA stability of the mutants ΔN127, R171X, P291fsinsC and T547E548fsdelTG is impaired compared to the wildtype sequence in transfected cells. This decreased RNA stability is independent of the presence of an intron in the expression vector and thus differs from mechanisms known to be involved in nonsensemediated decay (NMD). Our results suggest that haploinsufficiency of HNF1α is responsible for the pathogenesis of MODY3.

We describe a kindred from Mauritius with an incomplete variant of multiple endocrine neoplasia type 1 (MEN 1Burin). In this family the syndrome is related to a novel MEN 1gene mutation (deletion of A) at nucleotide 1021 of codon 304 resulting in frame shift and downstream protein truncation at codon 320. Compared to mainstream MEN 1, MEN 1Burinis characterized by a high prevalence of prolactin-secreting pituitary adenomas, late-onset of hyperparathyroidism and rare pancreatic involvement. The family described represents the fifth in the literature with the MEN 1Burinphenotype; 2 out of the other 4 were related to R460X, Y312X respectively and no mutation within the coding sequence of MEN 1was found in the other 2. Thus, similar to the classic syndrome, MEN 1Burinphenotype shows poor correlation to MEN 1genotype.

AimsTo detect clonal T cell populations by high resolution polymerase chain reaction (PCR) using fluorescently labelled nucleotides and analysis on an ABI 377 DNA sequencer, and to evaluate this method using low ionic strength single strand conformation polymorphism (LIS-SSCP) analysis.MethodsDNA samples from 11 patients diagnosed with a T cell disease and 15 with no known T cell disorder were amplified using four multiplex T cell receptor γ (TCRγ) PCR reactions containing fluorescently labelled nucleotides. PCR products were analysed using both LIS-SSCP electrophoresis and an ABI 377 DNA sequencer using Genescan^TM software. A Jurkat T cell leukaemia cell line was used to determine the sensitivity of the two methods.ResultsClonal TCRγ populations were detected in all 11 samples from patients with a T cell disease and no clonal populations were detected in samples from patients without a T cell disorder, using both LIS-SSCP and DNA sequencer analysis. Although the sensitivity of the two methods was comparable, the data generated by the sequencer were easier to interpret than the LIS-SSCP gels, and allowed accurate size determination of every product, which was not possible using LIS-SSCP.ConclusionsThe use of fluorescent labelled nucleotides provides a more flexible and economical alternative to end labelled fluorescent primers for the detection of clonal TCRγ gene rearrangements. This method allows clonal populations to be sized accurately and reproducibly, permitting the detection of identical clonal populations in different samples, and providing a method of monitoring disease progression and response to treatment.

AimsTo establish a robust method of extracting DNA from paraffin wax embedded bone marrow trephine (PBMT) biopsies for the amplification of relatively long polymerase chain reaction (PCR) products.MethodXylene and ethanol were used to remove paraffin wax from eight formalin fixed, EDTA decalcified PBMT biopsies and DNA extraction was performed using a Qiagen QIAamp tissue kit. The DNA samples were amplified using nine different PCR primers sets, including those used to detect chromosomal translocations t(11;14) and t(14;18), and clonal B cell populations. A t(11;14) PCR product of approximately 600 base pairs (bp) was sequenced using dye terminator cycle sequencing.ResultsAll eight DNA samples extracted from PBMT biopsies were amplified successfully to generate DNA fragments up to 643 bp in length. Chromosomal translocations and immunoglobulin gene rearrangements were detected by PCR in some of the samples. Sequencing of the t(11;14) PCR product demonstrated the presence of chimaeric sequences, which included both bcl-1 and immunoglobulin heavy chain (IgH) gene sequences, consistent with the presence of this translocation.ConclusionsThis method enables PCR analyses of PBMT biopsies that were not previously possible, offering the prospect of improved accuracy of diagnosis and the monitoring of patients with bone marrow disease.

Maturity-onset diabetes of the young (MODY) is a monogenic subgroup of non-insulin dependent diabetes mellitus (NIDDM) characterised by an early age of onset (< 25 years) and an autosomal dominant mode of inheritance. MODY is genetically heterogeneous with three different genes identified to date; hepatocyte nuclear factor 4 alpha (HNF-4α) [MODY1], glucokinase [MODY2] and hepatocyte nuclear factor 1 alpha (HNF-1α) [MODY3]. A nonsense mutation in the HNF-4α gene has recently been shown to cause MODY in a single large North American pedigree (RW). We screened a large UK Caucasian MODY family which showed weak evidence of linkage to the MODY1 locus on chromosome 20q (lod score for ADA 0.68 at θ= 0) for mutations in the coding region of the HNF-4α gene by direct sequencing. A missense mutation resulting in the substitution of glutamine for glutamic acid was identified in exon 7 (E276Q). The mutation was present in all of the diabetic members of the pedigree plus two unaffected subjects and was not detected in 75 normal control subjects or 95 UK Caucasian subjects with late-onset NIDDM. This is the first missense mutation to be described in the HNF-4α gene. [Diabetologia (1997) 40: 859–862]Maturity-onset diabetes of the young (MODY) is a monogenic subgroup of non-insulin dependent diabetes mellitus (NIDDM) characterised by an early age of onset (< 25 years) and an autosomal dominant mode of inheritance. MODY is genetically heterogeneous with three different genes identified to date; hepatocyte nuclear factor 4 alpha (HNF-4α) [MODY1], glucokinase [MODY2] and hepatocyte nuclear factor 1 alpha (HNF-1α) [MODY3]. A nonsense mutation in the HNF-4α gene has recently been shown to cause MODY in a single large North American pedigree (RW). We screened a large UK Caucasian MODY family which showed weak evidence of linkage to the MODY1 locus on chromosome 20q (lod score for ADA 0.68 at θ= 0) for mutations in the coding region of the HNF-4α gene by direct sequencing. A missense mutation resulting in the substitution of glutamine for glutamic acid was identified in exon 7 (E276Q). The mutation was present in all of the diabetic members of the pedigree plus two unaffected subjects and was not detected in 75 normal control subjects or 95 UK Caucasian subjects with late-onset NIDDM. This is the first missense mutation to be described in the HNF-4α gene. [Diabetologia (1997) 40: 859–862]

Abstract Mild hyperglycaemia is a common finding during minor illness in children. The differential diagnosis includes maturity onset diabetes of the young (MODY), which can be a difficult diagnosis to make clinically. As most genes resulting in MODY have been identified, it is possible to make a firm diagnosis using mutation detection. A case is reported of a 4 year old girl in whom a diagnosis of MODY2 was established by the finding of a heterozygous missense mutation in exon 7 of the glucokinase gene, resulting in the substitution at codon 259 of alanine by threonine (A259T). Observations from other glucokinase families suggest that hyperglycaemia in this child is likely to be stable and will not require intensive medical follow up, whereas other forms of MODY (1, 3, and 4) might carry a different prognosis.

Background & aims: Congenital hyperinsulinism (CHI) is a rare condition but a significant cause of recurrent hypoglycaemia in infancy and childhood. Prompt recognition and appropriate management is important to avoid long-term neurological sequelae. We aimed to describe the presentation, clinical and genetic outcomes in a series of infants with CHI.Methods: Retrospective case series of twenty-two patients diagnosed with CHI between 1992 and 2010 at The Children's University Hospital, Temple Street.Results: Fifteen of the twenty-two patients were male. Median age at presentation was day 2 (range: day 1- 18 months). Seizure was the most common presentation occurring in nine patients (40%). Mean glucose requirements to maintain euglycaemia were 14.6 mg/kg/min. First line treatment with diazoxide was commenced in all patients of whom twelve (54%) responded. Of those that did not respond to diazoxide, three were stabilized on octreotide and seven required surgery. One of these patients had a focal laparoscopic pancreatic resection, following pre-operative 18F-Fluorodopa positron emission tomography (18F-L -dopa PET). Genetic testing was performed on fifteen patients (68%). Five had a mutation(s) in the ABCC8 gene and two had mutations in the HNF4A gene. Twelve patients (54%) had a normal neurological outcome. Of the remaining ten, three patients had severe global developmental delay, three had moderate motor impairment and the remaining four patients had mild impairment.Conclusions: No clinical parameter significantly predicted outcome. Advances in both molecular genetics and 18F-L -dopa PET scanning will likely improve outcome for children diagnosed with CHI in the future.