Mapping the gene for autosomal dominant restless legs syndrome in an Irish family

Restless Legs Syndrome (RLS) is a common neurological disorder affecting nearly 15% of the general population. Ironically, RLS can be described as the most common condition one has never heard of. It is usually characterised by uncomfortable, unpleasant sensations in the lower limbs inducing an uncontrollable desire to move the legs. RLS exhibits a circadian pattern with symptoms present predominantly in the evening or at night, thus leading to sleep disruption and daytime somnolence. RLS is generally classified into primary (idiopathic) and secondary (symptomatic) forms. Primary RLS includes sporadic and familial cases of which the age of onset is usually less than 45 years and progresses slowly with a female to male ratio of 2:1. Secondary forms often occur as a complication of another health condition, such as iron deficiency or thyroid dysfunction. The age of onset is usually over 45 years, with an equal male to female ratio and more rapid progression. Ekbom described the familial component of the disorder in 1945 and since then many studies have been published on the familial forms of the disorder. Molecular genetic studies have so far identified ten loci (5q, 12q, 14p, 9p, 20p, 16p, 19p, 4q, 17p). No specific gene within these loci has been identified thus far. Association mapping has highlighted a further five areas of interest. RLS6 has been found to be associated with SNPs in the BTBD9 gene. Four other variants were found within intronic and intergenic regions of MEIS1, MAP2K5/LBXCOR1, PTPRD and NOS1. The pathophysiology of RLS is complex and remains to be fully elucidated. Conditions associated with secondary RLS, such as pregnancy or end-stage renal disease, are characterised by iron deficiency, which suggests that disturbed iron homeostasis plays a role. Dopaminergic dysfunction in subcortical systems also appears to play a central role. An ongoing study within the Department of Pathology (University College Cork) is investigating the genetic characteristics of RLS in Irish families. A three generation RLS pedigree RLS3002 consisting of 11 affected and 7 unaffected living family members was recruited. The family had been examined for four of the known loci (5q, 12q, 14p and 9p) (Abdulrahim 2008). The aim of this study was to continue examining this Irish RLS pedigree for possible linkage to the previously described loci and associated regions. Using informative microsatellite markers linkage was excluded to the loci on 5q, 12q, 14p, 9p, 20p, 16p, 19p, 4q, 17p and also within the regions reported to be associated with RLS. This suggested the presence of a new unidentified locus. A genome-wide scan was performed using two microsatellite marker screening sets (Research Genetics Inc. Mapping set and the Applied Biosystems Linkage mapping set version 2.5). Linkage analysis was conducted under an autosomal dominant model with a penetrance of 95% and an allele frequency of 0.01. A maximum LOD score of 3.59 at θ=0.00 for marker D19S878 indicated significant linkage on chromosome 19p. Haplotype analysis defined a genetic region of 6.57 cM on chromosome 19p13.3, corresponding to 2.5 Mb. There are approximately 100 genes annotated within the critical region. Sequencing of two candidate genes, KLF16 and GAMT, selected on the assumed pathophysiology of RLS, did not identify any sequence variant. This study provides evidence of a novel RLS locus in an Irish pedigree, thus supporting the picture of RLS as a genetically heterogeneous trait.

Victimisation of street children in Addis Ababa: factors of resilience and susceptibility

Cross-cultural variations in conceptions of childhood are discussed, particularly with regard to child abuse and child labour. Regardless of cultural background, a universal minimum standard of child rearing is required. The street child literature is reviewed, culminating in an analysis of Ethiopian street children. Theoretically this work is informed by victimology. Concepts shared by victimology and rational choice perspective are discussed, after Fattah (1993a). Victim surveys are described, highlighting their accuracy of crime estimates. Juvenile prostitution, runaways and rape are examined, particularly with regard to their relevance in Addis Ababa. Fifty five male and 135 female street children were interviewed. Interviews with boys focused on delinquency. An age-related pattern emerged, with younger boys less likely to drink, chew khat, steal or be sexually active. Interviews with street girls focused on the differences between girls living on the streets (girls of the street), girls working on the streets (girls on the street) and a sample of homebased girls. Girls of the street come to the street come to the streets for many reasons. Conflicts with a parent or guardian account for almost 50%. They are highly vulnerable to sexual assaults, particularly those 43% who have worked as prostitutes. Girls on the street experience considerably less victimisation. Urban poor girls live in socio-economic circumstances akin to girls on the street but enjoy almost universal protection from victimisation because they do not spend time on the streets. Unprotected by the stability which a family provides, girls of the street experience high victimisation levels. Such victimisation is often the result of reliance on types of work, such as prostitution, which brings the girls into contact with exploitative adults. Resistance to such victimisation is provided by a secure place to sleep, companions, and relatively safe types of work. Such protective factors are more readily available to family based children as compared to those living independently.