C.E.M. de Die-Smulders

Hereditary muscular dystrophies and the heart

Cardiac disease is a common clinical manifestation of neuromuscular disorders, particularly of muscular dystrophies. Heart muscle cells as well as specialized conducting myocardial fibres may be affected by the dystrophic process. The incidence and nature of cardiac involvement vary with different types of muscular dystrophies. Some mainly lead to myocardial disease, resulting in cardiomyopathy and heart failure, while others particularly affect the conduction system, leading to arrhythmias and sudden death. As prognosis of muscular dystrophy patients may be directly related to cardiac status, surveillance and timely management of cardiac complications are important. However, recognition of cardiac involvement requires active investigation and remains challenging since typical signs and symptoms of cardiac dysfunction may not be present and progression is unpredictable. In this review, we present a comprehensive overview of hereditary muscular dystrophies associated with cardiac disease to provide an efficient strategy for the expertise and management of these diseases.

The unfolding clinical spectrum of POLG mutations

Background: Mutations in the DNA polymerase-γ (POLG) gene are a major cause of clinically heterogeneous mitochondrial diseases, associated with mtDNA depletion and multiple deletions. Objective: To determine the spectrum of POLG mutations in our Dutch patient cohort, to evaluate the pathogenicity of novel mutations, and to establish genotype–phenotype correlations. Results: The authors identified 64 predominantly recessive mutations in 37 patients from a total of 232 patients, consisting of 23 different mutations. The substitution p.A467T was most frequently observed (n = 23), but was as frequent in childhood cases as in adult cases. Five new pathogenic recessive mutations, p.Lys925ArgfsX42, p.R275X, p.G426S, p.A804T and p.R869Q were identified. The known dominant chronic progressive external ophthalmoplegia (CPEO) mutation p.R943H was for the first time associated with premature ovarian failure as well. In 19 patients the authors identified only a single recessive mutation, or a sequence variant with unclear clinical significance. The data substantiate earlier observations that in POLG patients a fatal status epilepticus and liver failure can be triggered by sodium valproate. It is therefore important to exclude POLG mutations before administering this treatment. Conclusion: The clinical features of the patient are the most important features to select putative POLG mutation carriers and not the presence of mtDNA deletions or OXPHOS (oxidative phosphorylation) activity. The authors conclude that POLG mutations are an important cause of heterogeneous mitochondrial pathology and that more accurate genotype–phenotype correlations allow a more rapid genetic diagnosis and improved prognosis for mutation carriers.

Decision-making on preimplantation genetic diagnosis and prenatal diagnosis: a challenge for couples with hereditary breast and ovarian cancer

STUDY QUESTION How do couples with a BRCA1/2 mutation decide on preimplantation genetic diagnosis (PGD) and prenatal diagnosis (PND) for hereditary breast and ovarian cancer syndrome (HBOC)? SUMMARY ANSWER BRCA couples primarily classify PGD and/or PND as reproductive options based on the perceived severity of HBOC and moral considerations, and consequently weigh the few important advantages of PGD against numerous smaller disadvantages. WHAT IS KNOWN ALREADY Awareness of PGD is generally low among persons at high risk for hereditary cancers. Most persons with HBOC are in favour of offering PGD for BRCA1/2 mutations, although only a minority would consider this option for themselves. Studies exploring the motivations for using or refraining from PGD among well-informed BRCA carriers of reproductive age are lacking. We studied the reproductive decision-making process by interviewing a group of well-informed, reproductive aged couples carrying a BRCA1/2 mutation, regarding their decisional motives and considerations. STUDY DESIGN, SIZE, DURATION This exploratory, qualitative study investigated the motives and considerations taken into account by couples with a BRCA1/2 mutation and who have received extensive counselling on PGD and PND and have made a well-informed decision regarding this option. Eighteen couples took part in focus group and dyadic interviews between January and September 2012. PARTICIPANTS/MATERIALS, SETTING, METHODS Semi-structured focus groups were conducted containing two to four couples, assembled based on the reproductive method the couple had chosen: PGD (n = 6 couples) or conception without testing (n = 8 couples). Couples who had chosen PND for BRCA (n = 4) were interviewed dyadically. Two of the women, of whom one had chosen PND and the other had chosen no testing, had a history of breast cancer. MAIN RESULTS AND THE ROLE OF CHANCE None of the couples who opted for PGD or conception without testing found the use of PND, with possible pregnancy termination, acceptable. PND users chose this method because of decisive, mainly practical reasons (natural conception, high chance of favourable outcome). Motives and considerations regarding PGD largely overlapped between PGD users, PND users and non-users, all mentioning some significant advantages (e.g. protecting the child and family from the mutation) and many smaller disadvantages (e.g. the necessity of in vitro fertilization (IVF), low chance of pregnancy by IVF/PGD). For female carriers, the safety of hormonal stimulation and the time required for PGD before undergoing preventive surgeries were important factors in the decision. Non-users expressed doubts about the moral justness of their decision afterwards and emphasized the impact the decision still had on their lives. LIMITATIONS, REASON FOR CAUTION The interviewed couples were at different stages in their chosen trajectory, up to 3 years after completion. This may have led to recall bias of original motives and considerations. Couples who did not actively seek information about PGD were excluded. Therefore the results may not be readily generalizable to all BRCA couples. WIDER IMPLICATIONS OF THE FINDINGS The perceived severity of HBOC and, for female carriers, the safety of hormonal stimulation and the time frames for PGD planning before preventive surgeries are essential items BRCA couples consider in reproductive decision-making. The emotional impact of this decision should not be underestimated; especially non-users may experience feelings of doubt or guilt up to several years afterwards. PGD counselling with tailored information addressing these items and decisional support in order to guarantee well-informed decision-making is needed. STUDY FUNDING/COMPETING INTEREST(S) This study was funded by the Dutch breast cancer foundation Stichting Pink Ribbon, grant number 2010.PS11.C74. None of the authors have competing interests to declare. TRIAL REGISTRATION NUMBER Not applicable.

Molecular Analysis of Myophosphorylase Deficiency in Dutch Patients with McArdle's Disease

We report on 8 Dutch patients with McArdles disease from 6 unrelated families. Molecular analysis revealed the presence of four previously described mutations: the common R49X mutation, the IVS14+1G>A mutation and the recently reported R269X and Y84X nonsense mutations; and two new molecular defects: a missense mutation R138W in the homozygous state in two siblings, and a frameshift mutation c.1797delT. This first genetic study of patients from The Netherlands with McArdles disease confirms that the R49X mutation is also the most common in Dutch patients, and that there is genetic heterogeneity within this population. Moreover, our data support the hypothesis that the Y84X mutation is a relatively frequent mutation in McArdles patients with a Central European background, and expand the already crowded map of mutations within the PYGM gene responsible for McArdles disease.

Encephalopathic attacks in a family co-segregating myotonic dystrophy type 1, an intermediate Charcot-Marie-Tooth neuropathy and early hearing loss

Objective: To report new disease components in a unique myotonic dystrophy type 1 (DM1) family previously described by us in which all affected members also had a sensorimotor neuropathy that co-segregated with markers flanking the DM1 locus. Methods: Clinical observations, electrophysiology, audiometry, DNA studies. Results: During a follow-up period of over 25 years, the following were observed: (i) co-segregation of a striking new encephalopathic phenotype. In middle age, five patients were admitted on multiple occasions with attacks of impaired consciousness, psychomotor agitation, fever and, in about half of the cases, focal neurological signs, including unilateral weakness, sensory deficits and dysphasia. Reported onset phenomena consisted of confusion, headache, focal neurological symptoms and nausea; (ii) many patients show an early and severe sensorineural hearing loss; (iii) although they have mothers with the adult onset type, the four affected subjects from the youngest generation do not show any signs or symptoms of childhood or congenital myotonic dystrophy; (iv) the neuropathy meets the criteria of an intermediate type Charcot–Marie–Tooth (CMT), and is more severe in males; and (v) patients presented with an expanded fragment at the DM1 CTG repeat but this allele was refractory to PCR amplification and triplet repeat primed PCR at the 3′ end of the array, indicating the existence of an additional lesion at the 3′ end. Conclusions: The phenotype in this unique family extends beyond myotonic dystrophy and CMT to include encephalopathic attacks and early hearing loss, and is associated with an atypical mutation at the DM1 locus.

Awareness and attitude regarding reproductive options of persons carrying a BRCA mutation and their partners.

STUDY QUESTION To what extent are BRCA mutation carriers and their partners in the Netherlands aware about preimplantation genetic diagnosis (PGD) and prenatal diagnosis (PND) as reproductive options and what is their attitude towards these options? SUMMARY ANSWER Awareness of PGD (66%) and PND (61%) among BRCA mutation carriers and their partners is relatively high and 80% and 26%, respectively, of BRCA carriers and their partners find offering PGD and PND for hereditary breast and ovarian cancer (HBOC) acceptable. WHAT IS KNOWN ALREADY Internationally, awareness of PGD among persons with a genetic cancer predisposition appears to be relatively low (35%) and although acceptability is generally high (71%), only a small proportion of mutation carriers would consider using PGD (36%). However, for HBOC, there are no studies available that investigated the perspective of individuals with a confirmed BRCA1/2 mutation and their partners about PGD and PND including demographic and medical correlates of awareness and acceptability. STUDY DESIGN, SIZE, DURATION A cross-sectional survey was completed by 191 participants between July 2012 and June 2013. Participants were recruited through patient organizations (88%) and the databases of two Clinical Genetics departments in the Netherlands (12%). PARTICIPANTS/MATERIALS, SETTING, METHODS Male and female BRCA carriers and their partners completed an online survey, which assessed demographic and medical characteristics, and awareness, knowledge, acceptability and consideration of PGD and PND as main outcomes. Correlations between demographic and medical characteristics and the main outcomes were investigated. MAIN RESULTS AND ROLE OF CHANCE The majority of respondents were female (87%), of reproductive age (86%) and about half reported a desire for a child in the future. About two-thirds (66%) were aware of PGD and 61% of PND for HBOC. PGD knowledge was moderate (5.5 on a 9-point scale) and acceptability of PGD and PND for HBOC was 80% and 26%, respectively. A minority would personally consider using PGD (39%) or PND (20%). Individuals with a higher educational level were more likely to be aware of PGD (P < 0.001) and PND (P < 0.001) and persons with a more immediate child wish were more often aware of PGD (P = 0.044) and had more knowledge about PGD (P = 0.001). PGD acceptability was positively associated with knowledge about PGD (P = 0.047), and PND acceptability was higher among partners in comparison to carriers (P = 0.001). Participants with a history of cancer and with a higher perceived seriousness of breast and ovarian cancer were more likely to consider using PGD (P = 0.003 and P < 0.001 respectively) or PND (P = 0.021 and P = 0.017 respectively). LIMITATIONS, REASONS FOR CAUTION The response rate (23%) of participants invited by the clinical genetics departments was low, probably related to a simultaneous study that used a similar recruitment strategy within the same target group, which may have resulted in selection bias. Moreover, PGD knowledge was measured with an instrument that is not yet validated since to date such an instrument is not available in the literature. Finally, the cross-sectional design of this study limits us from drawing any causal conclusions. WIDER IMPLICATIONS OF THE FINDINGS Improvement of information provision remains needed, in order to timely inform all couples with HBOC about the available reproductive options and enable them to make a balanced reproductive decision. This may limit the risk of negative psychological impact due to decisional conflict and possible regret. STUDY FUNDING/COMPETING INTEREST(S) The Dutch breast cancer foundation Stichting Pink Ribbon (grant number 2010.PS11.C74). None of the authors have competing interests to declare. TRIAL REGISTRATION NUMBER Not applicable.

Refining the phenotypical and mutational spectrum of Taybi-Linder syndrome

Taybi‐Linder syndrome (TALS, OMIM 210710) is a rare autosomal recessive disorder belonging to the group of microcephalic osteodysplastic primordial dwarfisms (MOPD). This syndrome is characterized by short stature, skeletal anomalies, severe microcephaly with brain malformations and facial dysmorphism, and is caused by mutations in RNU4ATAC. RNU4ATAC is transcribed into a non‐coding small nuclear RNA which is a critical component of the minor spliceosome. We report here four foetuses and four unrelated patients with RNU4ATAC mutations. We provide antenatal descriptions of this rare syndrome including unusual features found in two twin foetuses with compound heterozygosity for two rare mutations who presented with mild intrauterine growth retardation and atypical dysmorphic facial features. We also carried out a literature review of the patients described up to now with RNU4ATAC mutations, affected either with TALS or Roifman syndrome, a recently described allelic disorder.

Reproductive Decision Support: Preferences and Needs of Couples at Risk for Hereditary Cancer and Clinical Geneticists

For couples at high risk of transmitting a cancer predisposition to offspring, reproductive decision-making can be challenging. As the choice between available reproductive options is preference-sensitive, the use of a decision aid can support these couples in their decisional process. The present study aims to investigate preferences and needs of involved stakeholders regarding the development and implementation of a patient decision aid. Semi-structured interviews assessing the needs and preferences regarding the content and functionalities of a decision support program were conducted among seven couples at risk for hereditary cancer and among eight clinical geneticists involved in oncogenetic counseling. Many similarities were found between the expressed preferences and needs of both stakeholder groups concerning the content, barriers and facilitating factors regarding the use of the decision aid, and its implementation. Emphasis was placed on the use of simple non-medical language, an extensive explanation of the procedures and techniques used in prenatal diagnosis (PND) and preimplantation genetic diagnosis (PGD), and the role of health care providers to refer couples to the decision aid. Both stakeholder groups were in favor of incorporating narrative stories in the decision aid. Integrating the present findings with knowledge on reproductive decisional motives and considerations is essential in guiding the development of a decision aid that corresponds to the preferences and needs of end-users. Trial registration: NTR5467

Professionals' knowledge, attitude and referral behaviour of preimplantation genetic diagnosis for hereditary breast and ovarian cancer

Hereditary breast and ovarian cancer caused by a BRCA1/2 mutation is the most frequent indication for preimplantation genetic diagnosis (PGD) in the Netherlands. The extent to which involved professionals are informed about this option, however, is unclear. The few available international studies mostly represent a limited range of professionals, and suggest that their knowledge about PGD for hereditary cancer syndromes is sparse and referral for PGD is based on limited understanding. A cross-sectional survey assessing awareness, knowledge, acceptability and PGD-referral for BRCA was completed by 188 professionals involved in the field of breast and ovarian cancer or reproduction. One-half of professionals were aware of PGD for BRCA, and most had a low to moderate level of knowledge. A total of 86% considered PGD for BRCA acceptable and 48% had referred patients with BRCA for PGD. Awareness and knowledge was higher among professionals who worked at a university hospital (compared with a general hospital). Knowledge of PGD was positively associated with discussing and referring for PGD, and PGD acceptability was associated with previous awareness. Although PGD counselling is the primary responsibility of the geneticist, other involved professionals may be gatekeepers as patients rely on them for raising awareness and referral.