An online survey to understand the needs of caregivers of family members with 22q11 deletion syndrome

BACKGROUND

Most individuals with 22q11.2 deletion syndrome (22q11DS) have multi-system and lifelong needs requiring substantial support. Their primary caregivers are usually family members who dedicate lifelong time and effort to their role. The pressures of their roles can negatively impact caregivers' psychosocial well-being, suggesting a need for additional support for this community who currently have no specialised interventions available.

METHOD

This online study surveyed 103 caregivers of family members with 22q11DS to determine the barriers to accessing support that they faced, the kind of support they would value and whether an online intervention could meet their needs.

RESULTS

The caregivers indicated that a brief online intervention focused on teaching practical skills and connecting them with a peer network of support would be most valuable.

CONCLUSIONS

Future studies are planned that will build on these results by designing and testing online interventions tailored to this community.

POS1554-HPR HEALTH PROFESSIONALS’ PERSPECTIVES ON THE USE OF JANUS KINASE INHIBITORS TO TREAT PATIENTS WITH INFLAMMATORY ARTHRITIS

Background

Janus kinase inhibitors (JAKi) are relatively new to the field of rheumatology and provide health professionals in rheumatology (HPRs) with more therapeutic options for treating inflammatory arthritis (IA), specifically rheumatoid arthritis (RA) and psoriatic arthritis (PsA) [1]. Aside from a different target, JAKi differ from often currently prescribed biologics by being administered orally. To date, there is a lack of evidence on what HPRs think about their real-world use and how the COVID-19 pandemic affects JAKi prescription.

Objectives

To explore UK-based HPRs’ perspectives towards JAKi use in IA patients, and in the context also of the COVID-19 pandemic.

Methods

A 15-item anonymous online survey, with both closed and open-ended questions, was designed and piloted on 5 HPRs with amendments made based on their feedback. The survey was advertised on Twitter and shared by email in September 2021. Data were exported from the online survey platform and analysed descriptively with the assistance of statistical software.

Results

Fifty-one HPRs responded to the survey: 37 Consultants, 7 Registrars, 5 Clinical Nurse Specialists, 1 Clinical Fellow and 1 ‘other rheumatology role’ (not stated). Responses were received from 11/12 UK regions. Most represented was Greater London (18%) and North-West England (16%). 69% of respondents worked in secondary care, with the remaining 31% in tertiary care. The majority (40%) spent 1-25% of their job role doing research, followed by 27% who were not research active.

60% of HPRs indicated that 1-5% of their RA and/or PsA patients take a JAKi (no HPRs had more than 15% of their RA/PsA patients on a JAKi). 96% of HPRs indicated that they prescribe JAKi in their clinical practice, with 91% of those who prescribe following their local guidelines. 72% of respondents who prescribe JAKi, prescribed them ‘frequently’ as a monotherapy. Figure 1 shows responses chosen for when JAKi therapy is usually started and for feeling less confident with JAKi prescription.

Of those HPRs who prescribe, 17% have continued JAKi in their patients. When discontinuation occurred, the most common reasons chosen (multiple responses allowed) were ‘due to inefficacy’ (60%), ‘due to other adverse events’ i.e., non-major adverse cardiovascular events (32%) and ‘due to herpes zoster infection’ (28%). 55% of HPRs would consider switching patients to another JAKi after initial failure.

Across prescribers, 49% indicated no impact of the COVID-19 pandemic on their prescribing of JAKi. Common reasons chosen for a change in prescribing patterns for JAKi as a result of the pandemic (multiple responses allowed) included: prescribing them more as ‘an alternative to infusions, in order to reduce hospital visits’ (23%) and as ‘an alternative to injections, in order to reduce at-home training visits’ (21%). This was followed by ‘other reason’ (15%) with the free text from all 7 respondents highlighting the benefits of the shorter half-life of JAKi e.g., “Prescribed more as quick on and quick off so can be discontinued quickly in event of severe infection” (Registrar, Greater London).

Safety concerns around the use of JAKi were raised in 13/14 free text comments left at the end of the survey e.g., “I am concerned about recent reports of increased VTE [venous thromboembolism] and malignancies” (Consultant, Yorkshire and the Humber) and “Concerns about cardiovascular safety” (Clinical Fellow, Scotland).

Conclusion

A large proportion of HPRs indicate confidence in prescribing JAKi to their patients with IA, adhering to local guidelines. JAKi are largely prescribed as monotherapy, with the most frequent reason for discontinuation being inefficacy. The COVID-19 pandemic seems to have positively impacted JAKi prescription, however, safety concerns over JAKi use remain for some HPRs.

References

[1]Bechman, K. et al. Pharmacol. Res. (2019) 147, 104392.

Acknowledgements

Thank you to all health professionals who piloted, completed and shared the survey. This study received funding from the Pfizer Inflammation ASPIRE 2020 Rheumatology International Developed Markets Competitive Grant Programme.

Disclosure of Interests

Savia de Souza: None declared, Andrew Bassett: None declared, Ruth Williams: None declared, Elena Nikiphorou Speakers bureau: Celltrion, Pfizer, Sanofi, Gilead, Galapagos, AbbVie, Lilly, Grant/research support from: Pfizer and Lilly.

The COVID-19 pandemic's impact on worry and medical disruptions reported by individuals with chromosome 22q11.2 copy number variants and their caregivers

BACKGROUND

The world has suffered immeasurably during the COVID-19 pandemic. Increased distress and mental and medical health concerns are collateral consequences to the disease itself. The Genes to Mental Health (G2MH) Network consortium sought to understand how individuals affected by the rare copy number variations of 22q11.2 deletion and duplication syndrome, associated with neurodevelopmental/neuropsychiatric conditions, were coping. The article focuses on worry and disruptions in medical care caused by the pandemic.

METHODS

The University of Pennsylvania COVID-19 Stressor List and care disruption questions were circulated by 22 advocacy groups in English and 11 other languages.

RESULTS

A total of 512 people from 23 countries completed the survey; most were caregivers of affected individuals. Worry about family members acquiring COVID-19 had the highest average endorsed worry, whilst currently having COVID-19 had the lowest rated worry. Total COVID-19 worries were higher in individuals completing the survey towards the end of the study (later pandemic wave); 36% (n = 186) of the sample reported a significant effect on health due to care interruption during the pandemic; 44% of individuals (n = 111) receiving care for their genetic syndrome in a hospital setting reported delaying appointments due to COVID-19 fears; 12% (n = 59) of the sample reported disruptions to treatments; and of those reporting no current disruptions, 59% (n = 269) worried about future disruptions if the pandemic continued. Higher levels of care disruptions were related to higher COVID-19 worries (Ps < 0.005). Minimal differences by respondent type or copy number variation type emerged.

CONCLUSIONS

Widespread medical care disruptions and pandemic-related worries were reported by individuals with 22q11.2 syndrome and their family members. Reported worries were broadly consistent with research results from prior reports in the general population. The long-term effects of COVID-19 worries, interruptions to care and hospital avoidance require further study.

Neurocognition and adaptive functioning in a genetic high risk model of schizophrenia

BACKGROUND

Identifying factors that influence the functional outcome is an important goal in schizophrenia research. The 22q11.2 deletion syndrome (22q11DS) is a unique genetic model with high risk (20-25%) for schizophrenia. This study aimed to identify potentially targetable domains of neurocognitive functioning associated with functional outcome in adults with 22q11DS.

METHODS

We used comprehensive neurocognitive test data available for 99 adults with 22q11DS (n = 43 with schizophrenia) and principal component analysis to derive four domains of neurocognition (Verbal Memory, Visual and Logical Memory, Motor Performance, and Executive Performance). We then investigated the association of these neurocognitive domains with adaptive functioning using Vineland Adaptive Behavior Scales data and a linear regression model that accounted for the effects of schizophrenia status and overall intellectual level.

RESULTS

The regression model explained 46.8% of the variance in functional outcome (p &lt; 0.0001). Executive Performance was significantly associated with functional outcome (p = 0.048). Age and schizophrenia were also significant factors. The effects of Executive Performance on functioning did not significantly differ between those with and without psychotic illness.

CONCLUSION

The findings provide the impetus for further studies to examine the potential of directed (early) interventions targeting Executive Performance to improve long-term adaptive functional outcome in individuals with, or at high risk for, schizophrenia. Moreover, the neurocognitive test profiles may benefit caregivers and clinicians by providing insight into the relative strengths and weaknesses of individuals with 22q11DS, with and without psychotic illness.

A neurogenetic model for the study of schizophrenia spectrum disorders: the International 22q11.2 Deletion Syndrome Brain Behavior Consortium

Rare copy number variants contribute significantly to the risk for schizophrenia, with the 22q11.2 locus consistently implicated. Individuals with the 22q11.2 deletion syndrome (22q11DS) have an estimated 25-fold increased risk for schizophrenia spectrum disorders, compared to individuals in the general population. The International 22q11DS Brain Behavior Consortium is examining this highly informative neurogenetic syndrome phenotypically and genomically. Here we detail the procedures of the effort to characterize the neuropsychiatric and neurobehavioral phenotypes associated with 22q11DS, focusing on schizophrenia and subthreshold expression of psychosis. The genomic approach includes a combination of whole-genome sequencing and genome-wide microarray technologies, allowing the investigation of all possible DNA variation and gene pathways influencing the schizophrenia-relevant phenotypic expression. A phenotypically rich data set provides a psychiatrically well-characterized sample of unprecedented size (n=1616) that informs the neurobehavioral developmental course of 22q11DS. This combined set of phenotypic and genomic data will enable hypothesis testing to elucidate the mechanisms underlying the pathogenesis of schizophrenia spectrum disorders.

Cerebral dopamine deficiency, plasma monoamine alterations and neurocognitive deficits in adults with phenylketonuria

BACKGROUND

Phenylketonuria (PKU), a genetic metabolic disorder that is characterized by the inability to convert phenylalanine to tyrosine, leads to severe intellectual disability and other cerebral complications if left untreated. Dietary treatment, initiated soon after birth, prevents most brain-related complications. A leading hypothesis postulates that a shortage of brain monoamines may be associated with neurocognitive deficits that are observable even in early-treated PKU. However, there is a paucity of evidence as yet for this hypothesis.

METHODS

We therefore assessed in vivo striatal dopamine D2/3 receptor (D2/3R) availability and plasma monoamine metabolite levels together with measures of impulsivity and executive functioning in 18 adults with PKU and average intellect (31.2 ± 7.4 years, nine females), most of whom were early and continuously treated. Comparison data from 12 healthy controls that did not differ in gender and age were available.

RESULTS

Mean D2/3R availability was significantly higher (13%; p = 0.032) in the PKU group (n = 15) than in the controls, which may reflect reduced synaptic brain dopamine levels in PKU. The PKU group had lower plasma levels of homovanillic acid (p < 0.001) and 3-methoxy-4-hydroxy-phenylglycol (p < 0.0001), the predominant metabolites of dopamine and norepinephrine, respectively. Self-reported impulsivity levels were significantly higher in the PKU group compared with healthy controls (p = 0.033). Within the PKU group, D2/3R availability showed a positive correlation with both impulsivity (r = 0.72, p = 0.003) and the error rate during a cognitive flexibility task (r = 0.59, p = 0.020).

CONCLUSIONS

These findings provide further support for the hypothesis that executive functioning deficits in treated adult PKU may be associated with cerebral dopamine deficiency.

Autism Spectrum and psychosis risk in the 22q11.2 deletion syndrome. Findings from a prospective longitudinal study

BACKGROUND

Individuals with 22q11.2 deletion syndrome (22q11DS) have a 25% risk for schizophrenia and related psychotic disorders. Some have hypothesized that Autism Spectrum Disorders (ASDs) diagnosed in children with 22q11DS may actually represent the social-communicative defects often observed during the early developmental stages of schizophrenia.

METHODS

We prospectively studied 89 children with 22q11DS to test this hypothesis. At baseline, the Autism Diagnostic Interview was used to assess ASD, evaluating both current and early childhood behaviors. At follow-up, the Schedule for Affective Disorders and Schizophrenia for School-Age Children (K-SADS) was used to determine development of a psychotic disorder or psychotic symptoms.

RESULTS

The average age (±SD) at first and last assessments was 14.3±1.9 and 19.0±3.0years, respectively. Nineteen (21.3%) children developed a psychotic disorder. Contrary to our hypothesis, there was no significant difference in the proportion that developed a psychotic disorder, comparing those with (n=9, 17.3%) and those without ASD at baseline (n=10, 27%; OR=0.500, 95% CI=0.160-1.569, p=0.235). Similar results were obtained using autistic symptom severity as quantitative predicting variable, psychotic symptoms as the outcome, and when correcting for age, gender and full scale IQ.

CONCLUSION

Results indicate that in children with 22q11DS, early childhood autistic features are not associated with an increased risk for subsequent development of psychotic disorders or symptoms, replicating previous retrospective findings in adults with 22q11DS. These results indicate that ASD and psychotic disorders can emerge independently, as pleiotropic phenotypes in the context of 22q11DS.

Pharmacological treatment of 22q11.2 deletion syndrome-related psychoses

In their recent article in Pharmacopsychiatry Verhoeven and Egger report a case series of 28 patients and state that "treatment of psychotic symptoms in patients with 22q11.2 deletion syndrome (22q11.2DS) with quetiapine or clozapine in combination with valproic acid appears likely to be more effective than with other psychotropic compounds". In this letter, we discuss the limitations of their case series and the lack of evidence for such a sweeping conclusion. In lieu of strong evidence to the contrary, standard pharmacological treatments of psychotic illness in 22q11.2DS remains recommended, with attention to 22q11.2DS-related issues. The latter would include management strategies to help ameliorate the elevated risk of seizures (e. g. when using clozapine), and vigilance for Parkinson's disease or other potential movement disorders.

Perceived burden and neuropsychiatric morbidities in adults with 22q11.2 deletion syndrome

BACKGROUND

22q11.2 deletion syndrome (22q11.2DS) is a common genetic subtype of intellectual disability (ID) remarkable for its constellation of congenital, developmental and later-onset features. Survival to adulthood is now the norm, and serious psychiatric illness is common in adults. However, little is known about the experiences and perceived needs of individuals with 22q11.2DS and their caregivers at time of transition from paediatric to adult models of care and beyond.

METHOD

We administered a mail survey to 84 caregivers of adults with 22q11.2DS and 34 adult patients themselves, inquiring about medical and social services, perceived burden and major challenges in adulthood in 22q11.2DS. Standard quantitative and qualitative methods were used to analyse the responses.

RESULTS

Fifty-three (63.1%) caregivers and 20 (58.8%) adults with 22q11.2DS completed the survey. Perceived burden was high, with psychiatric illness and/or behavioural issues considered the most challenging aspects of adulthood in 22q11.2DS by the majority of caregivers (70.0%) and many patients themselves (42.9%). Irrespective of the extent of ID and the presence or absence of other major features, caregivers expressed dissatisfaction with medical and social services for adults, including at time of transition from paediatric care.

CONCLUSIONS

To our knowledge, this is the first study to examine the subjective experiences of adults with 22q11.2DS and their caregivers and to identify their perceived needs for services. Better awareness of 22q11.2DS and its later-onset manifestations, early diagnosis and treatment of psychiatric illness, additional support at time of transition and dedicated clinics for adults with 22q11.2DS may help to improve patient outcomes and reduce caregiver burden.

Caregiver and adult patient perspectives on the importance of a diagnosis of 22q11.2 deletion syndrome

BACKGROUND

Recent advances in genetics are particularly relevant in the field of intellectual disability (ID), where sub-microscopic deletions or duplications of genetic material are increasingly implicated as known or suspected causal factors. Data-driven reports on the impact of providing an aetiological explanation in ID are needed to help justify widespread use of new and expensive genetic technologies.

METHODS

We conducted a survey of caregivers on the value of a genetic/aetiologic diagnosis of 22q11.2 deletion syndrome (22q11.2DS), the most common microdeletion syndrome in ID. We also surveyed the opinion of a high-functioning subset of adults with 22q11.2DS themselves. We used standard quantitative and qualitative methods to analyse the responses.

RESULTS

In total, 73 of 118 surveys were returned (61.9%). There was convergence of quantitative and qualitative results, and consistency between adult patient and caregiver responses. A definitive molecular diagnosis of 22q11.2DS was a critical event with diverse positive repercussions, even if occurring later in life. Frequently cited benefits included greater understanding and certainty, newfound sense of purpose and a platform for advocacy, and increased opportunities to optimise medical, social and educational needs.

CONCLUSIONS

This is the first study to characterise the impact of a diagnosis of this representative microdeletion syndrome on adult patients and their families. The results both validate and expand on the theoretical benefits proposed by clinicians and researchers. The use of genome-wide microarray technologies will provide an increasing number of molecular diagnoses. The importance of a diagnosis of 22q11.2DS demonstrated here therefore has implications for changing attitudes about molecular genetic diagnosis that could benefit individuals with ID of currently unknown cause and their families.

Premature death in adults with 22q11.2 deletion syndrome

BACKGROUND

22q11.2 deletion syndrome (22q11.2DS) is a multisystem disease with a prevalence of 1/4000. Variable expression of congenital and later onset features contributes to its under-recognition. Longevity in those surviving childhood is believed to be normal but data are limited.

METHODS

We prospectively followed 264 subjects; 102 adults (>17 years) with 22q11.2DS (44 male (M), 58 female (F); mean (SD) age 33.6 (10.9) years) and their 162 unaffected siblings (77 M, 85 F; mean age 36.1 (12.2) years). We compared survival between groups using Kaplan-Meier estimates.

RESULTS

Twelve (11.8%; 4 M, 8 F) individuals with 22q11.2DS and no siblings died (p<0.0001). Survival to ages 40 and 50 years was 89.9% and 73.9%, respectively. Median age at death was 41.5 (range 18.1-68.6) years. Deaths included two (7.7%) of 26 subjects with neither major congenital heart disease (CHD) nor schizophrenia. Four of six sudden and unexpected deaths occurred in individuals with no major CHD. There was no evidence of cancer or coronary artery disease or family history of sudden death in the 12 patients who died, six of whom had autopsies.

DISCUSSION

Individuals with 22q11.2DS who survive childhood have diminished life expectancy and increased risk of sudden death not attributable to any single factor. Some sudden and/or premature deaths observed in the general population may represent undiagnosed 22q11.2DS. Increased recognition of the syndrome by family doctors, specialists and coroners will be essential to facilitate the tissue studies needed to determine underlying mechanisms.

A posterior probability of linkage-based re-analysis of schizophrenia data yields evidence of linkage to chromosomes 1 and 17

OBJECTIVE

Linkage analysis using 22 Canadian pedigrees identified a promising schizophrenia candidate region on 1q23 with a maximum 2-point HLOD under a recessive model of 5.8 [Brzustowicz et al. 2000]. In the current study, we revisited this data set using a Bayesian linkage analysis technique, namely the posterior probability of linkage (PPL).

METHODS

The PPL has been developed as an alternative to traditional linkage analysis. It differs from both LOD scores and 'non-parametric' methods in that it directly measures the probability of linkage given the data, and incorporates prior genomic information.

RESULTS

As expected, PPL results for 1q23 supported the previously observed linkage, with an estimated multipoint PPL of 99.7%. However, the PPL supported two further results: a second peak on chromosome 1 at 1p13 with a multipoint with PPL of 70% and a chromosome 17 marker (D17S784 at 17q25) with a multipoint PPL of 44%.

CONCLUSIONS

The PPL-based analysis presented has the advantage over other likelihood-based linkage methods in that it avoids maximization and produces a less complex view of the strength of evidence for linkage.

Tumor necrosis factor promoter haplotype associated with schizophrenia reveals a linked locus on 1q44

Using restriction fragment length polymorphism and pyrosequencing methods, we genotyped two TNFA gene promoter SNPs (-G308A, -G238A) and analyzed the haplotype structure in 24 Canadian families of primarily Celtic origin. Our results demonstrate that after correction for multiple testing based on simulations of 10 000 replicates of unlinked/unassociated data, there is evidence for association (P=0.026) of a specific haplotype (-308A, -238G) with schizophrenia and schizophrenia spectrum disorders with a family-based trimmed haplotype linkage disequilibrium test (Trimhap). Stratifying the 22 families with genome scan data by TNFA promoter haplotypes followed by reanalysis of linkage to schizophrenia throughout the genome, we identified few loci that exhibit a considerable increase in LOD/HLOD scores. A locus on chromosome 1q44 (D1S1609) demonstrated a significant increase (P=0.025) in LOD score from 0.15 to 3.01 with a broad definition of the schizophrenia phenotype and a dominant mode of inheritance. This result replicates a previously reported positive result of linkage of schizophrenia spectrum disorders to this area of the genome. We also illustrated that simulation studies are pivotal in evaluating the significance of results obtained with newer statistical methods, when multiple, but not independent, tests are performed, and when sample stratification is utilized to reduce the impact of heterogeneity or assess the interaction between loci.

Elevated rates of schizophrenia in a familial sample with mental illness and intellectual disability

BACKGROUND

It is unknown whether intellectual disability (ID) is more familially related to psychotic mood disorders or schizophrenia. L. S. Penrose's large sample of families with two or more members admitted to psychiatric hospitals provided a unique opportunity to investigate the familial relationship between mild ID, schizophrenia and psychotic affective disorders.

METHOD

There were 183 affected relative pairs comprising probands with mild ID (95 male, 88 female) and their first or second degree relatives with schizophrenia or psychotic affective disorder.

RESULTS

There were nearly twice as many relatives with a diagnosis of schizophrenia (n = 121) as relatives with affective disorders (n = 62) among the intellectually impaired probands. This excess of schizophrenia was statistically significant, even after accounting for the increased risk of hospitalization for schizophrenia (P = 0.005), and was fairly constant across the different relative types. First-degree relatives with either mental illness were more likely to be parents (n = 77) than siblings (n = 51) or children (n = 3), but there was no excess of mother-son pairs.

CONCLUSIONS

These results suggest a stronger familial relationship of ID with schizophrenia than psychotic affective disorder, and lend some support to the neurodevelopmental hypothesis of schizophrenia.

Postmaturity in a genetic subtype of schizophrenia

OBJECTIVE

To determine whether postmaturity (gestation > 41 weeks), small for gestational age (SGA), and other pregnancy and birth complications that may elevate risk for neurodevelopmental disorders, are associated with elevated risk for schizophrenia in 22q11 Deletion Syndrome (22qDS), a genetic subtype of schizophrenia.

METHOD

Antepartum and intrapartum features were examined in 20 adults with 22qDS-schizophrenia and three comparison groups: newborn encephalopathy (n = 164) and healthy newborn controls (n = 400) from Badawi et al.'s (Br Med J 1998, 317: 1549) study, and 16 non-psychotic 22qDS adults (22qDS-NP).

RESULTS

Postmaturity (OR 13.0, 95% CI 3.95, 42.77; P < 0.001) and SGA (OR 3.59, 95% CI 1.23, 10.5; P = 0.03) were more prevalent in 22qDS-SZ than controls. Postmaturity was non-significantly more prevalent in 22qDS-SZ than in newborn encephalopathy (P = 0.06) or 22qDS-NP (P = 0.2). SGA showed similar rates in the two 22qDS groups and newborn encephalopathy, but was more prevalent in 22qDS-NP than controls (P = 0.05).

CONCLUSION

The results suggest that postmaturity may be associated with expression of schizophrenia in a 22qDS subtype of schizophrenia. SGA may be a non-specific marker of neurodevelopmental disturbance.

Genetic insights into the neurodevelopmental hypothesis of schizophrenia

The original neurodevelopmental hypothesis of schizophrenia presented by D.R. Weinberger in 1987 focused on pathogenesis and did not address etiology. Available evidence indicates that genetic factors are the principal cause of schizophrenia. It is imperative that any pathogenetic model for schizophrenia takes into account what is now known about genetic mechanisms of illness. Recent advances in molecular genetics can provide insights into the neurodevelopmental expression of the illness and what future genetic discoveries are likely to contribute to our understanding of schizophrenia. In this article, we propose a genetic model of etiopathogenesis that is consistent both with a modified neurodevelopmental hypothesis and our current knowledge about schizophrenia and molecular genetics.

Impaired olfactory identification in relatives of patients with familial schizophrenia

OBJECTIVE

Impaired olfactory identification ability has previously been demonstrated in patients with schizophrenia. This study assessed olfactory function in psychotic and nonpsychotic members of multigenerational families with familial schizophrenia to determine whether deficits were present in both groups.

METHOD

The University of Pennsylvania Smell Identification Test was administered birhinally to three groups of subjects aged less than 65 years: 19 psychotic and 27 nonpsychotic members of families with familial schizophrenia and 43 age- and sex-matched healthy volunteers.

RESULTS

Nonpsychotic family members had significantly higher mean University of Pennsylvania Smell Identification Test scores than psychotic family members but were impaired relative to the healthy volunteer group. These group differences could not be accounted for by age, sex, or smoking habit. Fifty-eight percent of the psychotic and 34% of the nonpsychotic family members performed in the microsmic (impaired) range, compared to 9% of the healthy volunteers.

CONCLUSIONS

Impaired olfactory deficits may aggregate in families with schizophrenia and may be indicative of a genetic predisposition to psychosis.

Genetic insights into schizophrenia

OBJECTIVE

To outline new insights into the genetic etiology of schizophrenia.

METHODS

We discuss several commonly held beliefs about the genetic issues in schizophrenia.

RESULTS

The complex genetic nature of the illness poses a challenge for investigators seeking causative genetic mutations. Multiple independent research findings are, however converging to identify a relatively small number of chromosomal locations that appear to contain schizophrenia susceptibility genes. Also, a clinically relevant genetic subtype of schizophrenia (22qDS) has been identified. We are developing a better understanding of how schizophrenia relates to other psychiatric disorders. While investigations into the possible roles of dopaminergic and serotonergic systems continue, other approaches that do not require theories of the mechanism of illness are also being used to identify candidate susceptibility genes.

CONCLUSIONS

Research to date suggests that our understanding of the pathophysiology of schizophrenia will soon be fundamentally altered by genetic approaches to this complex disease.

Genetic counselling for schizophrenia in the era of molecular genetics

OBJECTIVE

To review the role of genetic counselling for individuals with psychiatric illnesses.

METHOD

Using schizophrenia as an example and including updated information about a genetic subtype (22q deletion syndrome), we discuss the value of the genetic counselling process in psychiatry, with support from the literature and our clinical experience.

RESULTS

Genetic counselling, the process through which knowledge about the genetics of illnesses is shared, provides information on the inheritance of illnesses and their recurrence risks; addresses the concerns of patients, their families, and their health care providers; and supports patients and their families dealing with these illnesses. For comprehensive medical management, this service should be available to all individuals with schizophrenia and their families.

CONCLUSIONS

New findings in the genetics of psychiatric illness may have important clinical implications for patients and their families.

Location of a major susceptibility locus for familial schizophrenia on chromosome 1q21-q22

Schizophrenia is a complex disorder, and there is substantial evidence supporting a genetic etiology. Despite this, prior attempts to localize susceptibility loci have produced predominantly suggestive findings. A genome-wide scan for schizophrenia susceptibility loci in 22 extended families with high rates of schizophrenia provided highly significant evidence of linkage to chromosome 1 (1q21-q22), with a maximum heterogeneity logarithm of the likelihood of linkage (lod) score of 6.50. This linkage result should provide sufficient power to allow the positional cloning of the underlying susceptibility gene.

Chromosomal abnormalities and schizophrenia

Schizophrenia is a common and serious psychiatric illness with strong evidence for genetic causation, but no specific loci yet identified. Chromosomal abnormalities associated with schizophrenia may help to understand the genetic complexity of the illness. This paper reviews the evidence for associations between chromosomal abnormalities and schizophrenia and related disorders. The results indicate that 22q11.2 microdeletions detected by fluorescence in-situ hybridization (FISH) are significantly associated with schizophrenia. Sex chromosome abnormalities seem to be increased in schizophrenia but insufficient data are available to indicate whether schizophrenia or related disorders are increased in patients with sex chromosome aneuploidies. Other reports of chromosomal abnormalities associated with schizophrenia have the potential to be important adjuncts to linkage studies in gene localization. Advances in molecular cytogenetic techniques (i.e., FISH) have produced significant increases in rates of identified abnormalities in schizophrenia, particularly in patients with very early age at onset, learning difficulties or mental retardation, or dysmorphic features. The results emphasize the importance of considering behavioral phenotypes, including adult onset psychiatric illnesses, in genetic syndromes and the need for clinicians to actively consider identifying chromosomal abnormalities and genetic syndromes in selected psychiatric patients.

Qualitative MRI findings in adults with 22q11 deletion syndrome and schizophrenia

BACKGROUND

A genetic syndrome associated with schizophrenia, 22q11 deletion syndrome (22qDS), may represent a genetic subtype of schizophrenia (22qDS-Sz). Structural brain changes are common in schizophrenia and may involve developmental anomalies, but there are no data yet for 22qDS-Sz. The objective of this study was to assess brain structure in adults with 22qDS-Sz using magnetic resonance imaging (MRI).

METHODS

Brain and arterial MRI scans of 11 adults with 22qDS-Sz (mean age = 28.4 years, SD = 6.5) were systematically assessed by a neuroradiologist for qualitative anomalies.

RESULTS

A high frequency of abnormalities were found: T2 white matter bright foci (BF), 90%; developmental midline anomalies, 45%; cerebral atrophy or ventricular enlargement, 54%; mild cerebellar atrophy, 36%; skull base abnormalities, 55%; and minor vascular abnormalities, 36%.

CONCLUSIONS

BF and skull base abnormalities, especially in association with neurodevelopmental midline abnormalities, may be distinguishing MRI features for a genetic subtype of schizophrenia involving a deletion on chromosome 22.

Phenotype of adults with the 22q11 deletion syndrome: A review

22q11 deletion syndrome (22qDS) is due to microdeletions of chromosome region 22q11.2. Little is known about the phenotype of adults. We reviewed available case reports of adults (age >/=18 years) with 22qDS and compared the prevalence of key findings to those reported in a large European survey of 22qDS (497 children and 61 adults) [Ryan et al., 1997: J. Med. Genet. 34:798-804]. Fifty-five studies reported on 126 adults (83 women, 40 men, 3 unknown sex), mean age 29.6 years (SD = 8.7 years). Compared with the European survey, adults with 22qDS reviewed had a lower rate of CHD, 30% versus 75%; chi(2) = 88.65, df = 1, P < 0.0001, but higher rates of identified palate anomalies, 88% versus 15%; chi(2) = 37.45, df = 1, P < 0.0001, and learning difficulties, 94% versus 79%; chi(2) = 12.13, df = 1, P = < 0.0008. The most common finding reported was minor facial anomalies. Few reports provided details of minor physical anomalies. Psychiatric conditions were more prevalent, 36% versus 18%; chi(2)= 5.71, df = 1, P < 0.02, than in the survey: 60% of reviewed adults were transmitting parents (72% mothers) ascertained following diagnosis of affected offspring. They had lower rates of CHD, cleft palate, and psychiatric disorders but similar rates of learning disabilities, and other palate and facial anomalies compared with adults ascertained by other methods. The results suggest that learning disabilities and facial and palate anomalies may be key findings in 22qDS adults, but that ascertainment is a key factor in the observed phenotype. Comprehensive studies of adults with 22qDS identified independently of familial transmission are necessary to further delineate the phenotype of adults and to determine the natural history of the syndrome.

22q11 deletion syndrome: a genetic subtype of schizophrenia

Schizophrenia is likely to be caused by several susceptibility genes and may have environmental factors that interact with susceptibility genes and/or nongenetic causes. Recent evidence supports the likelihood that 22q11 Deletion Syndrome (22qDS) represents an identifiable genetic subtype of schizophrenia. 22qDS is an under-recognized genetic syndrome associated with microdeletions on chromosome 22 and a variable expression that often includes mild congenital dysmorphic features, hypernasal speech, and learning difficulties. Initial evidence indicates that a minority of patients with schizophrenia (approximately 2%) may have 22qDS and that prevalence may be somewhat higher in subpopulations with developmental delay. This paper proposes clinical criteria (including facial features, learning disabilities, hypernasal speech, congenital heart defects and other congenital anomalies) to aid in identifying patients with schizophrenia who may have this subtype and outlines features that may increase the index of suspicion for this syndrome. Although no specific causal gene or genes have yet been identified in the deletion region, 22qDS may represent a more homogeneous subtype of schizophrenia. This subtype may serve as a model for neurodevelopmental origins of schizophrenia that could aid in delineating etiologic and pathogenetic mechanisms.

Linkage of familial schizophrenia to chromosome 13q32

Over the past 4 years, a number of investigators have reported findings suggestive of linkage to schizophrenia, with markers on chromosomes 13q32 and 8p21, with one recent study by Blouin et al. reporting significant linkage to these regions. As part of an ongoing genome scan, we evaluated microsatellite markers spanning chromosomes 8 and 13, for linkage to schizophrenia, in 21 extended Canadian families. Families were analyzed under autosomal dominant and recessive models, with broad and narrow definitions of schizophrenia. All models produced positive LOD scores with markers on 13q, with higher scores under the recessive models. The maximum three-point LOD scores were obtained under the recessive-broad model: 3.92 at recombination fraction (theta).1 with D13S793, under homogeneity, and 4.42 with alpha=.65 and straight theta=0 with D13S793, under heterogeneity. Positive LOD scores were also obtained, under all models, for markers on 8p. Although a maximum two-point LOD score of 3.49 was obtained under the dominant-narrow model with D8S136 at straight theta=0.1, multipoint analysis with closely flanking markers reduced the maximum LOD score in this region to 2. 13. These results provide independent significant evidence of linkage of a schizophrenia-susceptibility locus to markers on 13q32 and support the presence of a second susceptibility locus on 8p21.

22q11 deletion syndrome in adults with schizophrenia

Genetic syndromes associated with deletions at chromosome 22q11 generally have been diagnosed during childhood based on a constellation of physical features. To investigate a reported association of velocardiofacial syndrome with psychotic disorders in adults, we assessed subjects with DSM-IV schizophrenia or schizoaffective disorder who were referred with two or more syndromal features (palatal, cardiac, facial, or other congenital anomalies, and/or learning difficulties). We report on 10 subjects (5 men and 5 women), mean age 27.2 (SD 6.0) years, who were found to have a 22q11 deletion at locus D22S75 using fluorescence in-situ hybridization (FISH). The mean age at onset of psychosis was 19.6 (SD 4.6) years. Symptoms and course of the psychotic illnesses were unremarkable, but additional signs such as temper outbursts were common. These adult subjects had significantly fewer major palatal (P = .0001) and conotruncal cardiac (P = .05) anomalies but the same high rate of learning difficulties as a sample with deletion 22q11 ascertained through a pediatric clinic [Lindsay et al. (1995): Am J Med Genet 57:514-522]. Minor congenital features and rate of transmitted cases were similar to those previously reported. These results replicate the association of a 22q11 deletion syndrome with schizophrenia and confirm the importance of ascertainment in influencing the phenotype found. The findings support a developmental gene in the 22q11 deletion region causing a complex phenotype which may include significant behavioral components that emerge over time. We support using the term "22q11 deletion syndrome (22DS)," which would encompass physical and psychiatric features, and could also be applied to describe a genetic subtype of schizophrenia.

Paternal transmission and anticipation in schizophrenia

Recent studies have observed anticipation (earlier age at onset (AAO) or increased disease severity in successive generations) in familial schizophrenia. In other disorders, where the molecular mechanism (repeat expansion) is known, anticipation varies in degree depending on the sex of the transmitting parent. We investigated parental sex effects on anticipation in schizophrenia, using a familial sample of affected two-generation pairs in which anticipation had previously been demonstrated using the median intergenerational difference (MID) in AAO. A Wilcoxon rank sum test for independent samples was used to determine whether MID in AAO was significantly different for paternal and maternal transmission. Results suggested that in a sample of 127 parent-offspring pairs, anticipation was greater with paternal than with maternal transmission (MID = 18 and 14 years, respectively, P = 0.05). Paternal effects were strongest in 39 parent-offspring pairs with early-onset offspring (< or = 21 years) (MID = 22 and 17 years, respectively, for paternal and maternal transmission, P = 0.01). However, assessment of the effect of possible selection biases suggests that preferential ascertainment of late-onset fathers may have exerted important effects. While the results support possible paternal effects, further studies are needed to draw firm conclusions about true parent-of-origin effects on anticipation in familial schizophrenia.

Use of a quantitative trait to map a locus associated with severity of positive symptoms in familial schizophrenia to chromosome 6p

A number of recent linkage studies have suggested the presence of a schizophrenia susceptibility locus on chromosome 6p. We evaluated 28 genetic markers, spanning chromosome 6, for linkage to schizophrenia in 10 moderately large Canadian families of Celtic ancestry. Parametric analyses of these families under autosomal dominant and recessive models, using broad and narrow definitions of schizophrenia, produced no significant evidence for linkage. A sib-pair analysis using categorical disease definitions also failed to produce significant evidence for linkage. We then conducted a separate sibpair analysis using scores on positive-symptom (psychotic), negative-symptom (deficit), and general psychopathology-symptom scales as quantitative traits. With the positive symptom-scale scores, the marker D6S1960 produced P = 1.2 x 10(-5) under two-point and P = 5.4 x 10(-6) under multipoint analyses. Using simulation studies, we determined that these nominal P values correspond to empirical P values of .034 and .0085, respectively. These results suggest that a schizophrenia susceptibility locus on chromosome 6p may be related to the severity of psychotic symptoms. Assessment of behavioral quantitative traits may provide increased power over categorical phenotype assignment for detection of linkage in complex psychiatric disorders.

The New York High-Risk Project. Prevalence and comorbidity of axis I disorders in offspring of schizophrenic parents at 25-year follow-up

BACKGROUND

The New York High-Risk Project is a study of offspring of patients with schizophrenia (HRSz group) or affective illness (HRAff group) and psychiatrically normal parents (NC group) observed prospectively from childhood to adulthood. We herein present lifetime prevalence and comorbidity rates of Axis I disorders in subjects and their siblings from sample A of the project.

METHODS

Schedule for Affective Disorders and Schizophrenia-Lifetime Version interviews conducted with the offspring in adulthood were used to obtain diagnoses of Axis I disorders.

RESULTS

Schizophrenia and unspecified psychoses occurred only in the HRSz group. However, schizoaffective and psychotic affective disorders occurred equally in the HRSz and HRAff groups. Total rates of psychosis in these groups were significantly higher than in the NC group. All groups had similar rates of nonpsychotic affective and substance abuse disorders. The HRAff group, however, had significantly more total affective illness than the NC group and tended to have more anxiety disorders than the other groups. Comorbidity rates in the HRSz and HRAff groups were nearly twice those of the NC group.

CONCLUSIONS

The familial liabilities to schizophrenia and affective disorders show specificities and commonalities, differing markedly from each other in their expression of some disorders and sharing others. Patterns of comorbidity are generally, although not entirely, similar to these liabilities.

A comprehensive method of assessing routine CT scans in schizophrenia

Morphological brain abnormalities are common in schizophrenia, although the aetiological and clinical significance of these findings is largely unknown. Substantial between-subject variability suggests that large samples are needed to study the full implications of brain pathomorphology. Computerized tomography (CT) is frequently used routinely in schizophrenia, and large numbers of scans are available for study. This article describes the development and statistical properties of a rapid and simple method of assessing CT scans. The CT Rating Scale for Schizophrenia (CTRSS) is minimally affected by variability in scanning procedures, is reliable, and accurately estimates area and volumetric measures of brain spaces. By promoting the comprehensive assessment of large numbers of routinely obtained scans, the CTRSS would allow the investigation of variables that may systematically affect results (e.g. gender and age) and variables with low prevalence. The CTRSS provides a useful adjunct to technologically more sophisticated methods of assessment such as magnetic resonance imaging (MRI).

Absence of linkage for schizophrenia on the short arm of chromosome 5 in multiplex Canadian families

A VNTR for the human dopamine transporter gene (DAT-1) has been localized to chromosome 5p15.3. Silverman et al. [1996] found evidence for genetic linkage of the D5S111 locus, located just centromeric to DAT-1, to schizophrenia and related disorders in a large Hispanic family. We evaluated five markers on 5p, including D5S111 and the DAT-1 VNTR, in five multiplex schizophrenic families, assuming autosomal dominant transmission (subjects assessed n = 122, DNAs available n = 96, individuals with schizophrenia and schizoaffective disorder n = 36, broader spectrum disorders n = 14). LOD scores were negative across all families for all markers tested, and overall LOD scores were strongly negative (<-2.0, theta = 0) across all five families for each of the markers typed. Thus, there is no evidence to support the linkage of markers in this region of chromosome 5 to schizophrenia in this sample of families.

Anticipation or ascertainment bias in schizophrenia? Penrose's familial mental illness sample

Several studies have observed anticipation (earlier age at onset [AAO] in successive generations) in familial schizophrenia. However, whether true anticipation or ascertainment bias is the principal originating mechanism remains unclear. In 1944 L. S. Penrose collected AAO data on a large, representative sample of familial mental illness, using a broad ascertainment strategy. These data allowed examination of anticipation and ascertainment biases in five two-generation samples of affected relative pairs. The median intergenerational difference (MID) in AAO was used to assess anticipation. Results showed significant anticipation in parent-offspring pairs with schizophrenia (n = 137 pairs; MID 15 years; P = .0001) and in a positive control sample with Huntington disease (n = 11; P = .01). Broadening the diagnosis of the schizophrenia sample suggested anticipation of severity of illness. However, other analyses provided evidence for ascertainment bias, especially in later-AAO parents, in parent-offspring pairs. Aunt/uncle-niece/nephew schizophrenia pairs showed anticipation (n = 111; P = .0001), but the MID was 8 years and aunts/uncles had earlier median AAO than parents. Anticipation effects were greatest in pairs with late-AAO parents but remained significant in a subgroup of schizophrenia pairs with early parental AAO (n = 31; P = .03). A small control sample of other diseases had MID of 5 years but no significant anticipation (n = 9; P = .38). These results suggest that, although ascertainment-bias effects were observed in parent-offspring pairs, true anticipation appears to be inherent in the transmission of familial schizophrenia. The findings support investigations of unstable mutations and other mechanisms that may contribute to true anticipation in schizophrenia.

NCAM and schizophrenia: genetic studies

The hypothesis of a neurodevelopmental dysfunction being involved in the etiology of schizophrenia is suggested by the observation of morphological alterations in the brains of schizophrenia patients. These alterations may be caused by defects in neural cell differentiation or migration, which could lead to disrupted neuronal circuitry and to the schizophrenia symptomatology. The neural cell adhesion molecule (NCAM) plays a major role in cell migration and axon outgrowth, and is involved in synaptic plasticity mechanisms implicated in adult cognitive functions. Altered levels of the NCAM polysialylated form, PSA-NCAM, in the brain of schizophrenia patients have been reported, and are supportive of a role for this molecule in the disorder. To investigate the possible involvement of the NCAM gene in schizophrenia, we conducted a comprehensive genetic study, which included linkage analysis and an association study employing the Haplotype Relative Risk (HRR) design in nuclear families. Our results indicate that structural alterations in the NCAM gene are unlikely to play a major role in schizophrenia, although a function for the NCAM molecule in the etiology of the disease remains an intriguing hypothesis.

Search for unstable DNA in schizophrenia families with evidence for genetic anticipation

Evidence for genetic anticipation has recently become an important subject of research in clinical psychiatric genetics. Renewed interest in anticipation was evoked by molecular genetic findings of a novel type of mutation termed "unstable DNA." The unstable DNA model can be construed as the "best fit" for schizophrenia twin and family epidemiological data. We have performed a large-scale Southern blot hybridization, asymmetrical PCR-based, and repeat expansion-detection screening for (CAG)n/(CTG)n and (CCG)n/(CGG)n expansions in eastern Canadian schizophrenia multiplex families demonstrating genetic anticipation. There were no differences in (CAG)n/(CTG)n and (CCG)n/(CGG)n pattern distribution either between affected and unaffected individuals or across generations. Our findings do not support the hypothesis that large (CAG)n/(CTG)n or (CCG)n/(CGG)n expansions are the major etiologic factor in schizophrenia. A separate set of experiments directed to the analysis of small (30-130 trinucleotides), Huntington disease-type expansions in individual genes is required in order to fully exclude the presence of (CAG)n/(CTG)n- or (CCG)n/(CGG)n-type unstable mutation.

Reproductive fitness in familial schizophrenia

BACKGROUND

Reproductive fitness is an important factor in understanding inheritance in genetic disorders. The purpose of this study was to determine whether fitness is reduced in familial schizophrenia (FS) and if fitness in siblings differs from the norm.

METHOD

The number of offspring in 36 subjects with RDC schizophrenia or schizoaffective disorder (SZ) and their 101 siblings from large FS families was compared with age-adjusted census figures.

RESULTS

Fitness in the SZ group was significantly reduced: 23% of expected in males and 51% of expected in females. Fitness of unaffected siblings was within census expectations. However, female siblings with schizophrenia spectrum features had increased fitness over census norms. Reduced fitness was correlated with low marital rates, poor functioning and positive symptoms.

CONCLUSIONS

These results indicate that reduced fitness is an important genetic force in FS and is likely inherent to the illness. Sex differences are important and would need to be considered when examining maternal and paternal transmission of schizophrenia. The results support a proposed high mutation rate for schizophrenia, consistent with a dynamic mutation mechanism.

Localization of the Darier disease gene to a 2-cM portion of 12q23-24.1

Positional cloning with microsatellite markers allowed further localization of the Darier disease gene to a 2-cM interval of chromosome 12, 12q23-24.1, between the polymorphic loci D12S234 and D12S129. A region this size is suitable for construction of a contig to identify the Darier disease gene. Use of a polymorphic intronic marker for nitric oxide synthetase 1 gene, which maps to the same chromosomal area as the Darier gene, allowed exclusion of that gene as the Darier disease gene.

Linkage analysis between schizophrenia and the Darier's disease region on 12q

There have been reports of an association between Darier's disease, an autosomal dominant genodermatosis, and psychiatric illness. Recently the gene causing Darier's disease has been mapped to an area on 12q, between D12S58 and D12S84. The findings of linkage analysis of 4 markers in the Darier's disease region on 12q in five families segregating schizophrenia are presented. They fail to support close linkage between schizophrenia and the Darier's disease region on 12q.

A case study of temporal lobe development in familial schizophrenia

Case studies of patients with familial schizophrenia may help to define the pathophysiology of this illness and indicate potential candidate genes for genetic linkage studies. In this regard, the clinical, radiological and pathological assessments of a 39-year-old affected man from a pedigree with familial schizophrenia are presented. Brain imaging with CT indicated moderate cortical atrophy, particularly of the temporal lobes. Neuropathological examination revealed granular ependymitis, indicating possible past ventricular pathology. Granular ependymitis was reported to occur in genetic developmental disorders with neuronal migration abnormalities. In the present case, heterotopic clusters of neurons were visualized in the entorhinal cortex, suggesting that temporal lobe development was not entirely normal. This case study suggests that genetic factors could be investigated further as one possible aetiology of certain neurodevelopmental abnormalities observed in schizophrenia.

The temporal lobes, reversed asymmetry and the genetics of schizophrenia

Mechanisms determining temporal lobe structural asymmetries may be involved in the pathogenesis of schizophrenia. To investigate the temporal lobes in familial schizophrenia, computed tomographic scans were obtained from 51 subjects (seven families). Enlargement of sylvian fissures and temporal lobe sulcal spaces was observed in family members with schizophrenia. The posterior one-third of the sylvian fissure was larger on the left side in subjects with schizophrenia, and larger on the right side in unaffected individuals. This disturbed pattern of posterior sylvian fissure asymmetry suggests that adjacent language regions may be affected in schizophrenia. An intermediate degree of disturbance in subjects who had schizophrenia-related illnesses or were obligate carriers suggests that genetic factors may be important determinants of temporal lobe asymmetries in familial schizophrenia.

The New York High-Risk Project. Psychoses and cluster A personality disorders in offspring of schizophrenic parents at 23 years of follow-up

BACKGROUND

We herein present lifetime prevalence rates of psychoses and DSM-III-R cluster A personality disorders in sample A of the New York High-Risk Project, a prospective study following offspring of parents with schizophrenia (HRSz subjects) and affective illness (HRAff subjects) and of psychiatrically normal parents (NC subjects) from midchildhood to adulthood.

METHODS

We interviewed the offspring in adulthood with the Schedule for Affective Disorders and Schizophrenia, Lifetime Version, for Axis I disorders and the Personality Disorder Examination for Axis II disorders.

RESULTS

Lifetime prevalence rates (+/- SE) of schizophrenia and unspecified psychosis were 11.1% +/- 4.3% and 5.6% +/- 3.1%, respectively, in the HRSz group and 0% in the HRAff and NC groups. Rates of schizoaffective disorder subclassified as mainly schizophrenic, however, were highest in the HRAff group. Rates of psychotic affective disorders did not differ between the HRSz and other groups. Age-corrected morbidity risks were similar to lifetime prevalence rates. Rates of the three cluster A personality disorders did not differ among the groups, but the combined rate was greater in the HRSz and HRAff groups than in the NC group.

CONCLUSIONS

Our data strongly support a specific familial liability to narrowly defined schizophrenia that is not shared by families of probands with affective disorder. Schizoaffective disorder and cluster A personality disorders, however, occur in families of both schizophrenic probands and probands with affective disorder. Psychotic affective disorders, which are not increased in HRSz subjects, do not appear to be an expression of the liability to schizophrenia.

Clinical use of clozapine in a major urban setting: one year experience

This paper examines the clinical and demographic data of patients in the Clozapine Distribution System in Metropolitan Toronto in the first year after its inception. One hundred and thirty-seven patients were approved for funding during the year. They tended to be young, chronically and markedly ill patients suffering from schizophrenia, primarily with treatment resistance as the reason for clozapine therapy. Only 55 patients completed at least six months of therapy; 15 patients discontinued clozapine before six months of treatment, mainly because of side-effects and/or patients' noncompliance with bloodwork. Three patients discontinued clozapine because of haematological compromise. Clozapine was efficacious for the majority of patients who took it for at least six months, with improvement in all six clinical dimensions examined in the study. Nevertheless, the number of early discontinuation patients significantly lowered the overall effectiveness of clozapine in actual clinical practice.

Genetic linkage for Darier disease (keratosis follicularis)

Darier disease is an autosomal dominant skin disorder characterized by abnormal keratinocyte adhesion. Recent data have provided evidence for linkage of the Darier disease locus to 12q23-24.1 in British families. We have carried out linkage analysis using the 12q markers D12S58, D12S84, D12S79, D12S86, PLA2, and D12S63 in 6 Canadian families. Pairwise linkage analysis generated positive lod scores at all 6 markers at various recombination fractions, and each family showed positive lod scores with more than one marker. The peak lod score in the multipoint analysis (Zmax) was 5.5 in the interval between markers D12S58 and D12S84. These positive lod scores in North American families of varied European ancestry confirm the location of the Darier disease gene, and suggest genetic homogeneity. The future identification and sequencing of the gene responsible for Darier disease should lead to improved understanding of the disease and of keratinocyte adhesion in general.