Aideen McInerney-Leo

Midbrain dopamine and prefrontal function in humans: interaction and modulation by COMT genotype

Using multimodal neuroimaging in humans, we demonstrate specific interactions between prefrontal activity and midbrain dopaminergic synthesis. A common V(108/158)M substitution in the gene for catecholamine-O-methyltransferase (COMT), an important enzyme regulating prefrontal dopamine turnover, predicted reduced dopamine synthesis in midbrain and qualitatively affected the interaction with prefrontal cortex. These data implicate a dopaminergic tuning mechanism in prefrontal cortex and suggest a systems-level mechanism for cognitive and neuropsychiatric associations with COMT.

Parkinsonism among Gaucher disease carriers

An association between Gaucher disease and Parkinson disease has been demonstrated by the concurrence of Gaucher disease and parkinsonism in rare patients and the identification of glucocerebrosidase mutations in probands with sporadic Parkinson disease. Using a different and complementary approach, we describe 10 unrelated families of subjects with Gaucher disease where obligate or confirmed carriers of glucocerebrosidase mutations developed parkinsonism. These observations indicate that mutant glucocerebrosidase, even in heterozygotes, may be a risk factor for the development of parkinsonism. Understanding the relationship between altered glucocerebrosidase and the development of parkinsonian manifestations will provide insights into the genetics, pathogenesis, and treatment of Parkinson disease.

Defects in the IFT-B Component IFT172 Cause Jeune and Mainzer-Saldino Syndromes in Humans

Intraflagellar transport (IFT) depends on two evolutionarily conserved modules, subcomplexes A (IFT-A) and B (IFT-B), to drive ciliary assembly and maintenance. All six IFT-A components and their motor protein, DYNC2H1, have been linked to human skeletal ciliopathies, including asphyxiating thoracic dystrophy (ATD; also known as Jeune syndrome), Sensenbrenner syndrome, and Mainzer-Saldino syndrome (MZSDS). Conversely, the 14 subunits in the IFT-B module, with the exception of IFT80, have unknown roles in human disease. To identify additional IFT-B components defective in ciliopathies, we independently performed different mutation analyses: candidate-based sequencing of all IFT-B-encoding genes in 1,467 individuals with a nephronophthisis-related ciliopathy or whole-exome resequencing in 63 individuals with ATD. We thereby detected biallelic mutations in the IFT-B-encoding gene IFT172 in 12 families. All affected individuals displayed abnormalities of the thorax and/or long bones, as well as renal, hepatic, or retinal involvement, consistent with the diagnosis of ATD or MZSDS. Additionally, cerebellar aplasia or hypoplasia characteristic of Joubert syndrome was present in 2 out of 12 families. Fibroblasts from affected individuals showed disturbed ciliary composition, suggesting alteration of ciliary transport and signaling. Knockdown of ift172 in zebrafish recapitulated the human phenotype and demonstrated a genetic interaction between ift172 and ift80. In summary, we have identified defects in IFT172 as a cause of complex ATD and MZSDS. Our findings link the group of skeletal ciliopathies to an additional IFT-B component, IFT172, similar to what has been shown for IFT-A.

Clinical and positron emission tomography of Parkinson's disease caused by LRRK2

We have recently identified mutations in a gene leucine‐rich repeat kinase–2 (LRRK2), which cause autosomal dominant Parkinsons disease. Here, we describe two families with autosomal dominant Parkinsons disease caused by a LRRK2 G2019S mutation. We present here a clinical description of patients, including 6‐18F‐fluoro‐L‐dopa positron emission tomography and discuss the potential implications of this mutation, which alters a conserved residue in a domain required for kinase activation. Ann Neurol 2005;57:453–456

Short-Rib Polydactyly and Jeune Syndromes Are Caused by Mutations in WDR60

Short-rib polydactyly syndromes (SRPS I-V) are a group of lethal congenital disorders characterized by shortening of the ribs and long bones, polydactyly, and a range of extraskeletal phenotypes. A number of other disorders in this grouping, including Jeune and Ellis-van Creveld syndromes, have an overlapping but generally milder phenotype. Collectively, these short-rib dysplasias (with or without polydactyly) share a common underlying defect in primary cilium function and form a subset of the ciliopathy disease spectrum. By using whole-exome capture and massive parallel sequencing of DNA from an affected Australian individual with SRPS type III, we detected two novel heterozygous mutations in WDR60, a relatively uncharacterized gene. These mutations segregated appropriately in the unaffected parents and another affected family member, confirming compound heterozygosity, and both were predicted to have a damaging effect on the protein. Analysis of an additional 54 skeletal ciliopathy exomes identified compound heterozygous mutations in WDR60 in a Spanish individual with Jeune syndrome of relatively mild presentation. Of note, these two families share one novel WDR60 missense mutation, although haplotype analysis suggested no shared ancestry. We further show that WDR60 localizes at the base of the primary cilium in wild-type human chondrocytes, and analysis of fibroblasts from affected individuals revealed a defect in ciliogenesis and aberrant accumulation of the GLI2 transcription factor at the centrosome or basal body in the absence of an obvious axoneme. These findings show that WDR60 mutations can cause skeletal ciliopathies and suggest a role for WDR60 in ciliogenesis.

Turner Syndrome: Four Challenges Across the Lifespan

Turner syndrome (TS) is a sex chromosome condition that occurs in approximately 1/2,500 live female births. Despite the prevalence of this chromosomal condition, the challenges these women face throughout their lives are not fully understood. This qualitative research study aimed to characterize the subjective experiences of individuals with TS throughout their lifespan, to investigate their concerns and obstacles, and to offer insight into the strengths and weaknesses of health care delivery, as they perceived them. Ninety‐seven girls and women with TS and 21 parents consented to participate in this interview study. Interviews were semi‐structured and open‐ended in design. Questions sought to elicit responses relating to existing concerns associated with their condition and positive and negative health care experiences. Participants were divided into four age categories (childhood, adolescence, adulthood, and mature adulthood) to facilitate a comparative analysis across the age spectrum. Regardless of age, infertility was the most frequently cited concern followed closely by short stature. Sexual development and function and general health were also viewed as challenges by a number of participants in each age group. Although the relative weight of these four concerns tended to shift based upon the individuals age and life experiences, all four issues remained significant throughout the lifespan. Enhanced awareness of the evolving physical and psychological challenges faced by girls and women with TS may help health care providers (HCPs) improve the quality of life for these individuals. Published 2005 Wiley‐Liss, Inc.

Genetic testing in Parkinson's disease.

Parkinsons disease (PD) is a common neurodegenerative disorder of adulthood characterized clinically by rigidity, bradykinesia, resting tremor, and postural instability. The annual incidence of PD ranges between 16 and 19 individuals per 100,000 (Twelves et al., Mov Disord 2003;18:19-31). Historically, PD has been commonly viewed as an idiopathic or environmentally triggered condition. However, as is true with most common conditions, there have been several families reported with PD who demonstrate a classic Mendelian pattern of inheritance. To date, nine genetic loci have been reported and four pathogenic genes have been identified: alpha-synuclein, parkin, DJ1, and PINK1. Families with alterations in these genes or linked sites demonstrate either recessive or dominant inheritance patterns and may have typical and/or atypical symptoms, with an age of onset extending from the second to the sixth decade. Commercial tests for parkin and alpha-synuclein mutations are now available. We predict that physicians, particularly neurologists, increasingly will be approached for information and referrals regarding genetic testing. To assist patients and their families, physicians will not only need to know when such testing is likely to yield a meaningful result but also be aware of the possible social and emotional consequences of testing. The following is a review of what is currently known about the genetics of PD within this context. We discuss what is known about genetic testing for Huntingtons disease, a well-described model for genetic testing in a neurodegenerative disorder. We explore the utility, appropriateness, and possible implications of genetic testing for diagnostic and presymptomatic purposes.

BRCA1/2 testing in hereditary breast and ovarian cancer families II: Impact on relationships†

Members of hereditary breast and ovarian cancer (HBOC) families often express concern during genetic counseling about the impact of BRCA1/2 testing on close relatives. Yet whether there are likely to be adverse effects of either the decision to undergo genetic testing or the results of testing on family relationships is unknown. One purpose of this study was to assess the impact on close family relationships. Within a randomized trial of breast cancer genetic counseling methods, members of 13 HBOC families were offered BRCA1/2 testing for a known family mutation. The Family Relationship Index (FRI) of the Family Environment Scale (FES) was used to measure perceived family cohesion, conflict, and expressiveness at baseline and again 6–9 months following the receipt of test results, or at the equivalent time for those who declined testing. Participants (n = 212) completed baseline and follow‐up questionnaires. Comparisons were made between testers and non‐testers as well as between those who tested positive and negative for the family mutation. One hundred eighty‐one participants elected to undergo genetic testing (85%) and 47 (26%) were identified to have a mutation. After adjusting for baseline family relationship scores, counseling intervention, gender and marital status, non‐testers reported a greater increase in expressiveness (P = 0.006) and cohesion (P = 0.04) than testers. Individuals who tested positive reported a decrease in expressiveness (P = 0.07), although as a trend. Regardless of test decision or test result, those who were randomized to a client‐centered counseling intervention reported a decrease in conflict (P = 0.006). Overall, study results suggest that undergoing genetic testing and learning ones BRCA1/2 status may affect family relationships. Those individuals who declined testing reported feeling closer to family members and more encouraged to express emotions to other family members demonstrating potential benefit from the offer of testing. Since those who tested positive reported feeling less encouraged to express their emotions within the family, we recommend helping clients to identify others with whom they feel comfortable sharing their thoughts and feelings about their positive gene status and increased cancer risk. Published 2005 Wiley‐Liss, Inc.

Genetic testing in Parkinson's disease: Genetic Testing in Parkinson's Disease

Parkinsons disease (PD) is a common neurodegenerative disorder of adulthood characterized clinically by rigidity, bradykinesia, resting tremor, and postural instability. The annual incidence of PD ranges between 16 and 19 individuals per 100,000 (Twelves et al., Mov Disord 2003;18:19–31). Historically, PD has been commonly viewed as an idiopathic or environmentally triggered condition. However, as is true with most common conditions, there have been several families reported with PD who demonstrate a classic Mendelian pattern of inheritance. To date, nine genetic loci have been reported and four pathogenic genes have been identified: α‐synuclein, parkin, DJ1, and PINK1. Families with alterations in these genes or linked sites demonstrate either recessive or dominant inheritance patterns and may have typical and/or atypical symptoms, with an age of onset extending from the second to the sixth decade. Commercial tests for parkin and α‐synuclein mutations are now available. We predict that physicians, particularly neurologists, increasingly will be approached for information and referrals regarding genetic testing. To assist patients and their families, physicians will not only need to know when such testing is likely to yield a meaningful result but also be aware of the possible social and emotional consequences of testing. The following is a review of what is currently known about the genetics of PD within this context. We discuss what is known about genetic testing for Huntingtons disease, a well‐described model for genetic testing in a neurodegenerative disorder. We explore the utility, appropriateness, and possible implications of genetic testing for diagnostic and presymptomatic purposes. Published 2004 John Wiley & Sons

BRCA1/2 testing in hereditary breast and ovarian cancer families: Effectiveness of problem‐solving training as a counseling intervention

It remains uncertain whether members of hereditary breast and ovarian cancer (HBOC) families experience psychological distress with genetic testing and whether pre‐test counseling can have a moderating effect on client well‐being. One purpose of this study was to assess change in psychological well‐being from baseline to 6–9 months follow‐up and the effect of a problem‐solving training (PST) intervention on psychological well‐being. Two hundred and twelve members of 13 HBOC families were offered BRCA1/2 testing for a previously identified family mutation. Participants received education and were randomized to one of two counseling interventions; PST or client‐centered counseling. Psychological well‐being was assessed at baseline and again at 6–9 months following the receipt of test results, or at the equivalent time for those participants who chose not to undergo testing. Well‐being was assessed using measures of depressive symptoms (CESD), intrusive thoughts (IES), cancer worries, and self‐esteem. Comparisons were made between those who chose testing and those who did not as well as between those who received positive and negative test results. One hundred eighty one participants elected to undergo genetic testing (85%) and 47 of these (26%) were identified as BRCA1/2 mutation carriers. Breast and ovarian cancer worries decreased significantly (p = 0.007 and 0.008, respectively) in those who tested negative while there was no appreciable change in psychological well‐being from baseline to follow‐up in either those who tested positive or in non‐testers. Among all participants, particularly testers, those randomized to PST had a greater reduction in depressive symptoms than those randomized to client‐centered counseling (p < 0.05 and p = 0.02, respectively). Regardless of the decision to test, individuals with a personal history of cancer (n = 22) were more likely to have an increase in breast cancer worries compared to those who had never been diagnosed with cancer (p < 0.001). Results suggest that a problem‐solving counseling intervention may help to enhance psychological well‐being following testing and that a personal history of cancer may increase psychological distress associated with genetic testing. Published 2004 Wiley‐Liss, Inc.