Cognition in children with neurofibromatosis type 1: data from a population-based study.

AIM: This study aimed to investigate the core cognitive deficits in children with neurofibromatosis type 1 (NF1). METHOD: The study recruited 49 children with NF1 (25 males, 24 females; mean age 11y 9mo [SD 3y 2mo]), 19 healthy siblings of children with NF1 (sibling comparisons; mean age 12y 7mo [SD 2y 7mo], 9 males, 10 females) and 29 healthy children from the community (community comparisons; mean age 11y [SD 2y 7mo], 12 males, 17 females). Participants completed a battery of cognitive tests including tests of intelligence, academic achievement, attention, visuoperceptual functioning, visual learning, executive functioning, and non-verbal working memory tests. RESULTS: Our study, using a population-based sample, confirmed previous findings from studies using variable sampling methods. Children with NF1 had significantly lower Full-scale IQs (p=0.04) and lower academic achievement (p=0.026-0.005) than their siblings. Compared with their siblings, they also had significantly poorer visuospatial processing (p=0.007), visual associate learning (p=0.014), non-verbal working memory (p=0.023), and executive function (p<0.001). Data from the community comparisons were not included because they were subject to significant selection bias. INTERPRETATION: Population-based frequencies for cognitive deficits in children with NF1 are similar to the frequencies in non-population based samples. This study highlights the heterogeneous nature of cognitive problems in children with NF1 and the need for monitoring and support at school.

Behaviour in children with neurofibromatosis type 1: cognition, executive function, attention, emotion, and social competence.

AIM: This systematic review aimed to pull together the findings from research into behavioural systems and attention in children with neurofibromatosis type 1 (NF1) and to identify areas that need further study. METHOD: Relevant papers were identified through searches of electronic databases (MEDLINE, PsycINFO, EMBASE) and manual searches through reference lists. In total, 5746 articles were identified and 57 met the inclusion criteria. The data were synthesized using the narrative approach, as the studies varied considerably in terms of participants and measures. RESULTS: The results of the review showed that intelligence, academic skills, visuospatial skills, social competence, and attention are impaired in children with NF1. Evidence of deficits in memory, motor functioning, language, and executive functions was less clear. INTERPRETATION: Research has made marked progress in outlining the behavioural phenotype of NF1. However, although the general areas of impairment are becoming better known, the exact nature of the impairment is still not understood in many areas of behaviour. Care needs to be taken with the way in which behavioural constructs are defined and measured, and the variability of problems in NF1 is a particular challenge. Nevertheless, research is steadily moving towards comprehensive understanding of behaviour in children with NF1.

Autism and other psychiatric comorbidity in neurofibromatosis type 1: evidence from a population-based study.

AIM: To investigate psychopathology in children with neurofibromatosis type 1 (NF1), particularly the prevalence of autism spectrum disorder (ASD) and attention-deficit-hyperactivity disorder (ADHD) symptomatology, using a population-based sampling approach. METHOD: Standard questionnaire screen reports were analysed for ASD (Social Responsiveness Scale, SRS), ADHD (Conners' Parent Rating Scale- Revised, CPRS-R), and other psychiatric morbidity (Strengths and Difficulties Questionnaire, SDQ) from parents and teachers of children aged from 4 to 16 years (112 females, 95 males) on the UK North West Regional Genetic Service register for NF1. RESULTS: Parental response rate was 52.7% (109/207 children; 59 females, 50 males, mean age 9 y 11 mo, SD 3 y 3 mo). The SRS showed that in 29.4% (32/109) of children, autism was in the severe, clinical range (T-score>75) and in 26.6% (29/109) in the mild to moderate range (T-score 60-75). CPRS-R scores showed that in 53.8% (57/106) of children autism was in the clinical ADHD range (ADHD index T-score>65). Based on their scores on the SDQ total difficulties scale, 41.5% (44/106) of children were in the abnormal range and 14.2% (15/106) were in the borderline range. Twenty-five per cent (26/104) of children met criteria for both clinical autism and ADHD. INTERPRETATION: This representative population-based sample of children with NF1 indicates a high prevalence of ASD symptoms associated with NF1 as well as substantial co-occurrence with ADHD symptoms. The findings clarify the psychopathology of NF1 and show the disorder as a potentially important single-gene cause for autism symptoms.

Predictors of cognitive, behavioural and academic difficulties in NF1.

The impact of the Neurofibromatosis type 1 (NF1) on cognition have been subject to much clinical investigation, but environmental modifiers of disease expression have not yet been systematically investigated. The aim of this paper is to determine the role of demographic and environmental factors such as age, sex, socioeconomic status, parental NF1 status and neurological complications on the cognitive, behavioural and academic outcomes in NF1. Participants included 206 children aged 4-18 years seen within the Manchester clinical research NF1 service. Multiple linear regression models were used to study the effect of the hypothesized predictor variables on cognitive, behavioural and academic outcomes. Relative to population norms, 80% of the NF1 sample demonstrated significantly lower scores in at least one cognitive, behavioural or academic domains. Family history of NF1 and lower SES were independently associated with poorer cognitive, behavioural and academic outcomes. Neurological problems such as epilepsy and hydrocephalus were associated with lower IQ and academic skills. Cognitive and behavioural phenotypes emerge commonly via a complex interplay between genes and environmental factors, and this is true also of a monogenic condition such as NF1. Early interventions and remedial education may be targeted to risk groups such those with familial NF1, families with lower SES and those with associated neurological comorbidities.

Effects of preoccupation on interpersonal recall: a pilot study.

BACKGROUND: The aim of this pilot study was to examine whether priming preoccupation (rumination) in healthy participants adversely affects the processing of interpersonal information. METHODS: Sixty female undergraduates with moderate or marked preoccupation proneness (selected on the basis of their high preoccupation on eating, shape, and weight issues) were randomized to receive either a general preoccupation prime, a standardized preoccupation prime, or a control prime. Following the prime, participants watched an 8-min videotape of a family interaction and then were asked free recall questions about the tape. RESULTS: Participants who received the general preoccupation prime scored lower than the other two groups in response to free recall questions regarding emotion-related topics. CONCLUSIONS: These findings suggest that when primed by everyday worries and concerns, individuals prone to preoccupation may have their capacity to recall emotion-related interpersonal information compromised.

The influence of postnatal psychiatric disorder on child development. Is maternal preoccupation one of the key underlying processes?

There is considerable evidence that maternal postnatal psychiatric disorder has an adverse influence on infant development. In attempting to examine the pathways of intergenerational transmission, most research has concentrated on genetic factors or on maternal behaviours during mother-child interaction and attachment. However, researchers have largely ignored the possible role of maternal cognition underlying behaviour, especially the thought and attentional processes involved in psychiatric disorders. This paper argues that a particular form of maternal cognition, namely 'preoccupation', is one key, but under-recognised, mechanism in the transmission of psychiatric disturbance. We propose that preoccupation interferes with specific aspects of mental functioning, especially attention and responsivity to the environment. This impairs the mother's parenting capacities and adversely affects mother-child interaction and child development.

Social Functioning and Behaviour in Mucopolysaccharidosis IH [Hurlers Syndrome].

BACKGROUND: Mucopolysaccharidosis type IH (MPS-IH) [Hurlers Syndrome] is a developmental genetic disorder characterised by severe physical symptoms and cognitive decline. This study aimed to investigate the behavioural phenotype of MPS-IH treated by haematopoietic cell transplantation, focusing on social functioning and sleep. Parental stress was also measured. METHODS: Participants were 22 children with MPS-IH (mean age 9 years 1 month), of whom 10 were male (45%). Parents completed the Social Responsiveness Scale (SRS), Child Behaviour Checklist (CBCL), Children's Sleep Habit Questionnaire and Parent Stress Index, Short Form (PSI-SF). RESULTS: Twenty-three per cent of children with MPS-IH scored in the severe range of the SRS, suggesting significant difficulties in social functioning. Children with MPS-IH were more than 30 times more likely to receive scores in the severe range than typically developing children. Thirty-six per cent scored in the mild-to-moderate range, suggesting milder, but marked, difficulties in social interaction. Although children with MPS-IH did not show significantly higher rates of internalising, externalising or total behaviour problems than the normative sample, they received scores that were significantly higher on social, thought and attention problems and rule-breaking behaviour, and all the competence areas of the CBCL. Parents of children with MPS-IH did not score significantly higher on parental stress than parents in a normative sample. CONCLUSIONS: Parents of children with MPS-IH rate their children as having problems with social functioning and various areas of competence more frequently than previously thought, with implications for clinical support.

Further evidence of inherited long QT syndrome gene mutations in antiarrhythmic drug-associated torsades de pointes.

BACKGROUND: Pathophysiologically significant ion-channel mutations have been detected in only a minority of cases of acquired long QT syndrome (LQTS). OBJECTIVE: The aim of this study was to clarify the putative role of subclinical inherited LQTS in drug-associated torsades de pointes (TdP) and to assess the concomitant proarrhythmic factors. METHODS: We evaluated 16 consecutive cases with documented, antiarrhythmic drug-induced TdP who were referred to the Laboratory of Molecular Medicine at Helsinki University for LQTS genetic testing between September 2000 and August 2005. RESULTS: A prolonged QTc interval was observed in 56% of the patients before administration of the drug. TdP was associated with amiodarone in seven, sotalol in six, flecainide in two, and propafenone in one of the cases. Except for the culprit drug, one or more risk factors such as female sex, congestive heart failure, and atrial fibrillation were present in each drug-associated TdP. DNA samples were screened for the four common Finnish founder mutations (KCNQ1 G589D and IVS7-2A-->G, HERG L552S, and R176W), which are known to account for the majority of inherited LQTS in Finland. A total of three (19%) individuals carried one of these four mutations. CONCLUSIONS: Our data show that previously unsuspected LQTS mutations may be present in patients with antiarrhythmic drug-associated TdPs. A normal QTc interval does not exclude the risk of proarrhythmia.

Maternal postnatal depression and anxiety and their association with child emotional negativity and behavior problems at two years.

Postnatal maternal depression is associated with poorer child emotional and behavioral functioning, but it is unclear whether this occurs following brief episodes or only with persistent depression. Little research has examined the relation between postnatal anxiety and child outcomes. The present study examined the role of postnatal major depressive disorder (MDD) and generalized anxiety disorder (GAD) symptom chronicity on children's emotional and behavioral functioning at 24 months. Following postnatal screening mothers (n = 296) were identified as having MDD, GAD, MDD and GAD, or no disorder at 3 months postnatal; the average age was 32.3 (SD = 5.0), 91.9% self-identified as Caucasian, and 62.2% were married. Maternal disorder symptom severity was assessed by questionnaires and structured interview at 3, 6, 10, 14, and 24 months postpartum. At 24 months, child emotional negativity and behavior were assessed using questionnaires and by direct observation. Latent trait-state-occasion modeling was used to represent maternal disorder symptom chronicity; both stable trait and time-specific occasion portions of maternal symptomatology were examined in relation to child outcomes. Only the stable trait portion of maternal MDD and GAD symptom severity were related to maternal report of child behavior problems and higher levels of emotional negativity. Persistent maternal MDD, but not GAD, symptom severity was related to higher levels of child emotional negativity as measured observationally. These data suggest that children's behavior problems and emotional negativity are adversely affected by persistent maternal depression, and possibly anxiety. This has implications for interventions to prevent negative effects of postnatal psychopathology on children. (PsycINFO Database Record

Catecholaminergic polymorphic ventricular tachycardia: recent mechanistic insights.

Cardiac excitation-contraction coupling occurs by a calcium ion-mediated mechanism in which the signal of action potential is converted into Ca2+ influx into the cardiomyocytes through the sarcolemmal L-type calcium channels. This is followed by Ca2+-induced release of additional Ca2+ ions from the lumen of the sarcoplasmic reticulum into the cytosol via type 2 ryanodine receptors (RyR2). RyR2 channels form large complexes with additional regulatory proteins, including FKBP12.6 and calsequestrin 2 (CASQ2). Catecholamines, released into the body fluids during emotional or physical stress, activate Ca2+-induced Ca2+ release by protein kinase A-mediated phosphorylation of RyR2. Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an insidious, early-onset and highly malignant, inherited disorder characterized by effort-induced ventricular arrhythmias in the absence of structural alterations of the heart. At least some cases of sudden, unexplained death in young individuals may be ascribed to CPVT. Mutations of the RyR2 gene cause autosomal dominant CPVT, while mutations of the CASQ2 gene may cause an autosomal recessive or dominant form of CPVT. The steps of the molecular pathogenesis of CPVT are not entirely clear, but inappropriate "leakiness" of RyR2 channels is thought to play a role; the underlying mechanisms may involve an increase in the basal activity of the RyR2 channel, alterations in its phosphorylation status, a defective interaction of RyR2 with other molecules or ions, such as FKBP12.6, CASQ2, or Mg2+, or its abnormal activation by extra- or intraluminal Ca2+ ions. Beta-adrenergic antagonists have proven to be of value in prevention of arrhythmias in CPVT patients, but occasional treatment failures call for alternative measures. There is great interest at present for the development of novel antiarrhythmic drugs for CPVT, as the same approaches may be applied for treatment of more common forms of life-threatening arrhythmias, such as those arising during ischemia and heart failure.

Neurofibromatosis type 1 and autism spectrum disorder.

OBJECTIVE: To determine the prevalence of autism spectrum disorder (ASD) in Neurofibromatosis Type 1 (NF1). METHODS: Second-phase population-based epidemiologic study using an allcase NF1 registry in a defined UK 4.1 million population area. A total of 109 (52.7%) of 207 responders from the initial screening phase were grouped by using the parent-rated Social Responsiveness Scale (SRS) as significant ASD (SRS≥76; n = 32), moderate ASD (SRS ≥ 60<76; n = 29), or non-ASD (SRS <60, n = 48). Twenty-three cases from the significant ASD group, 16 from moderate ASD, and 8 from non-ASD (total n = 47), invited proportionately by random selection, were seen for detailed confirmatory ascertainment. Assessments on Autism Diagnostic Interview-Revised, Autism Diagnostic Observation Scale-Generic, and verbal IQ were combined by using standard Collaborative Program for Excellence in Autism criteria into an ASD categorization for each case (ASD, broad ASD with partial features, non-ASD). A preplanned weighted analysis was used to derive prevalence estimates for the whole population. RESULTS: Fourteen (29.5%) of 47 showed ASD, 13 (27.7%) broad ASD, and 20 (42.5%) non-ASD. The ASD/broad ASD group showed male predominance (1.7:1.0), but did not differ significantly from the non-ASD group on IQ, age, socioeconomic status, inheritance, physical severity, or education. The population prevalence estimate is 24.9% ASD (95% confidence interval 13.1%-42.1%) and 20.8% broad ASD (95% confidence interval 10.0%-38.1%); a total of 45.7% showing some ASD spectrum phenotype. CONCLUSIONS: Findings indicate high prevalence of ASD in NF1, with implications for clinical practice and further research into NF1 as a single-gene model for autism.

Effects of reboxetine and citalopram on appraisal of infant facial expressions and attentional biases.

Difficulties in mother-child interaction are commonly observed in the context of postnatal depression. These difficulties may result in part from the negative cognitive bias present in depression, which may in turn lead to biased negative perceptions of the infant: in particular, these biases encompass the negative appraisal of facial expressions. Given the important role of early mother-child interactions in child development it is vital to investigate potential interventions that might be beneficial in ameliorating the negative cognitive bias. This study aimed to examine the effects of two different antidepressants (reboxetine and citalopram) on the appraisal of infant facial expressions of emotion using a faces rating task, and on attention to infant emotion using an attentional probe. Thirty-nine volunteers were randomly assigned to a double-blind 7-day intervention with either placebo, citalopram or reboxetine. There were significant positive effects on the appraisal of facial expressions; participants assigned to the placebo group rated positive faces less positively than those either in the citalopram or in the reboxetine groups. However, there was no evidence that these drugs had an effect on attentional vigilance. If antidepressants are able to help a mother to perceive her infant's facial expressions as more positive, this may lead to more positive interactions, thereby potentially mitigating the negative effects of depression on infant development. These findings should be treated with caution until replicated in larger and clinical samples.

Maternal cognitions and mother-infant interaction in postnatal depression and generalized anxiety disorder.

Postnatal depression and anxiety have been shown to increase the risk of disturbances in mother-child interaction and child development. Research into mechanisms has focused on genetics and maternal behavior; maternal cognitions have received little attention. Our aim was to experimentally determine if worry and rumination in mothers with generalized anxiety disorder (GAD) and major depressive disorder (MDD), diagnosed in the postnatal 6 months, interfered with maternal responsiveness to their 10-month old infants. Mothers (N = 253: GAD n = 90; MDD n = 57; control n = 106) and their infants were randomized to either a worry/rumination prime (WRP) or a neutral prime (NP); mother-infant interactions were assessed before and after priming. Type of priming was a significant predictor of maternal cognitions, with WRP resulting in more negative thoughts, higher thought recurrence and more self-focus relative to NP across the entire sample. Interaction effects between group and priming were significant for two parenting variables: Compared with controls, WRP had a more negative impact on maternal responsiveness to infant vocalization for GAD, and to a lesser extent for MDD; WRP led to decreased maternal vocalization for GAD. Also, mothers with GAD used stronger control after the NP than WRP, as well as compared with other groups, and overall post-priming, their children exhibited lower emotional tone and more withdrawal. Across the entire sample, WRP was associated with increased child vocalization relative to NP. This study demonstrated that disturbances in maternal cognitions, in the context of postnatal anxiety and to a lesser degree depression, play a significant role in mother-child interaction.

The effects of postnatal maternal depression and anxiety on the processing of infant faces.

BACKGROUND: Postnatally depressed mothers have difficulties responding appropriately to their infants. The quality of the mother-child relationship depends on a mother's ability to respond to her infant's cues, which are largely non-verbal. Therefore, it is likely that difficulties in a mother's appraisal of her infants' facial expressions will affect the quality of mother-infant interaction. This study aimed to investigate the effects of postnatal depression and anxiety on the processing of infants' facial expressions. METHOD: A total of 89 mothers, 34 with Generalised Anxiety Disorder, 21 with Major Depressive Disorder, and 34 controls, completed a 'morphed infants' faces task when their children were between 10 and 18 months. RESULTS: Overall, mothers were more likely to identify happy faces accurately and at lower intensity than sad faces. Depressed compared to control participants, however, were less likely to accurately identify happy infant faces. Interestingly, mothers with GAD tended to identify happy faces at a lower intensity than controls. There were no differences between the groups in relation to sad faces. LIMITATIONS: Our sample was relatively small and further research is needed to investigate the links between mothers' perceptions of infant expressions and both maternal responsiveness and later measures of child development. CONCLUSION: Our findings have potential clinical implications as the difficulties in the processing of positive facial expressions in depression may lead to less maternal responsiveness to positive affect in the offspring and may diminish the quality of the mother-child interactions. Results for participants with GAD are consistent with the literature demonstrating that persons with GAD are intolerant of uncertainty and seek reassurance due to their worries.

Mindful Parenting in Mental Health Care.

Mindfulness is a form of meditation based on the Buddhist tradition, which has been used over the last two decades to successfully treat a multitude of mental health problems. Bringing mindfulness into parenting ("mindful parenting") is one of the applications of mindfulness. Mindful parenting interventions are increasingly being used to help prevent and treat mental disorders in children, parenting problems, and prevent intergenerational transmission of mental disorders from parents to children. However, to date, few studies have examined the hypothesized mechanisms of change brought about by mindful parenting. We discuss six possible mechanisms through which mindful parenting may bring about change in parent-child interactions in the context of child and parent mental health problems. These mechanisms are hypothesized to be mediated by the effects of mindfulness on parental attention by: (1) reducing parental stress and resulting parental reactivity; (2) reducing parental preoccupation resulting from parental and/or child psychopathology; (3) improving parental executive functioning in impulsive parents; (4) breaking the cycle of intergenerational transmission of dysfunctional parenting schemas and habits; (5) increasing self-nourishing attention; and (6) improving marital functioning and co-parenting. We review research that has applied mindful parenting in mental health settings, with a focus on evidence for these six mechanisms. Finally, we discuss directions for future research into mindful parenting and the crucial questions that this research should strive to answer.

Interpretation of infant facial expression in the context of maternal postnatal depression.

Postnatal maternal depression is associated with difficulties in maternal responsiveness. As most signals arising from the infant come from facial expressions one possible explanation for these difficulties is that mothers with postnatal depression are differentially affected by particular infant facial expressions. Thus, this study investigates the effects of postnatal depression on mothers' perceptions of infant facial expressions. Participants (15 controls, 15 depressed and 15 anxious mothers) were asked to rate a number of infant facial expressions, ranging from very positive to very negative. Each face was shown twice, for a short and for a longer period of time in random order. Results revealed that mothers used more extreme ratings when shown the infant faces (i.e. more negative or more positive) for a longer period of time. Mothers suffering from postnatal depression were more likely to rate negative infant faces shown for a longer period more negatively than controls. The differences were specific to depression rather than an effect of general postnatal psychopathology-as no differences were observed between anxious mothers and controls. There were no other significant differences in maternal ratings of infant faces showed for short periods or for positive or neutral valence faces of either length. The findings that mothers with postnatal depression rate negative infant faces more negatively indicate that appraisal bias might underlie some of the difficulties that these mothers have in responding to their own infants signals.

Plakophilin-2 missense mutations in arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND: Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is an inherited cardiac disorder characterized by life-threatening ventricular arrhythmias and fibrofatty replacement of myocardial tissue. Recent data suggest a dominant mode of inheritance in ARVD due to mutations in desmosomal proteins, plakophilin-2 (PKP2) in particular. We carried out a search for PKP2 mutations in the Finnish population representing a genetic isolate. METHODS: Mutations were detected by direct sequencing of PKP2 exons in 29 unrelated ARVD patients. Subcellular changes in ARVD associated with PKP2 mutations were searched for using immunohistochemistry and electron microscopy. RESULTS: We identified three PKP2 amino acid substitutions, absent in controls, in three (10%) cases. Two of them (Q62K and N613K) co-occurred in a patient with arrhythmia and structural changes of the heart. Visualized with plakophilin-2 antibodies, the intercalated disks in this compound heterozygous ARVD sample appeared wavier than in non-ARVD controls. Partial irregularities were occasionally seen in the organization and distribution of the cell-cell junctions. Relatives carrying one of these mutant alleles were phenotypically normal or showed only limited electrocardiographic (ECG) changes. The third substitution (Q59L) was detected in two ARVD probands with ventricular tachycardias, ECG abnormalities and right ventricular structural alterations. CONCLUSIONS: We identified two novel plakophilin-2 missense mutations associated with 10% of ARVD, and a previously reported Q62K variant with a possible disease modifying role. The low prevalence of predominantly missense mutations may present population-specific differences in the pathogenesis of ARVD. Our preliminary data also suggest that ultrastructural cell junction abnormalities may associate with plakophilin-2 mutations.

A specific and rapid neural signature for parental instinct.

Darwin originally pointed out that there is something about infants which prompts adults to respond to and care for them, in order to increase individual fitness, i.e. reproductive success, via increased survivorship of one's own offspring. Lorenz proposed that it is the specific structure of the infant face that serves to elicit these parental responses, but the biological basis for this remains elusive. Here, we investigated whether adults show specific brain responses to unfamiliar infant faces compared to adult faces, where the infant and adult faces had been carefully matched across the two groups for emotional valence and arousal, as well as size and luminosity. The faces also matched closely in terms of attractiveness. Using magnetoencephalography (MEG) in adults, we found that highly specific brain activity occurred within a seventh of a second in response to unfamiliar infant faces but not to adult faces. This activity occurred in the medial orbitofrontal cortex (mOFC), an area implicated in reward behaviour, suggesting for the first time a neural basis for this vital evolutionary process. We found a peak in activity first in mOFC and then in the right fusiform face area (FFA). In mOFC the first significant peak (p<0.001) in differences in power between infant and adult faces was found at around 130 ms in the 10-15 Hz band. These early differences were not found in the FFA. In contrast, differences in power were found later, at around 165 ms, in a different band (20-25 Hz) in the right FFA, suggesting a feedback effect from mOFC. These findings provide evidence in humans of a potential brain basis for the "innate releasing mechanisms" described by Lorenz for affection and nurturing of young infants. This has potentially important clinical applications in relation to postnatal depression, and could provide opportunities for early identification of families at risk.

Characterization of familial and sporadic arrhythmogenic right ventricular cardiomyopathy in Finland.

BACKGROUND: Autosomal dominant inheritance is reported in arrhythmogenic right ventricular cardiomyopathy (ARVC) but the prevalence of the familial and sporadic forms in the general population is unknown. AIM: To evaluate the familial occurrence and clinical features of ARVC in the genetically homogenous Finnish population. METHODS: The study included 29 Finnish ARVC index patients and 135 relatives from 21 families evaluated. They underwent echocardiography, 24-hour electrocardiographic monitoring, signal-averaged electrocardiography, and exercise stress test. RESULTS: Twenty-two index patients had ventricular arrhythmias as first manifestation, and three developed arrhythmias later. The right ventricle (RV) was mildly affected in 22 and strongly dilated in 7 index patients. Patients with dilated RV manifested first symptoms at younger age (mean 28 years) than those without RV dilatation (mean 38 years). Of the 135 relatives, ARVC was present in 12 (9%) patients belonging to 5 of the 21 families studied, resulting in 24% familial involvement. In addition, 46 relatives (34%) had subtle cardiac abnormalities, suggesting subclinical presentation. CONCLUSIONS: The ARVC in Finland presents with distinct arrhythmic and RV dilative subtypes. The sporadic disease is similar to the familial one which may reflect low penetration in relatives. The proportion of familial manifestation of ARVC in Finland seems comparable to that elsewhere in Europe.

Doublet challenge: form comes before function in children's understanding of their orthography.

Several current spelling models suggest that children cannot have any knowledge of orthographic form before they have acquired knowledge about orthographic function. We evaluated this proposition by using an orthographic choice task to inspect Finnish schoolchildren's knowledge of two aspects of consonant doublet use: the allowed doublet position (an aspect of orthographic form) and the type of phonemic information they represent (an aspect of orthographic function). The results challenged the view of the existing spelling models, since they showed that already at the beginning of the first school year children possessed formal knowledge of doublet use and knew that word-initial doublets are not allowed. However, these children were ignorant of the function of doublets, i.e. that they stand for long consonants.