FLUIDOS DE BASE AGUA

A mutation in the UCH-Ll gene has been described in a kindred of German descent

(Leroy et al., 1998). The role of UCH-Ll has been described in section 1.14.4. To

examine the importance of the Ile93Met mutation in the UCH-Ll gene, two types of study were performed. The first study involved sequencing an index case from families with 3 or more affecteds and a history of PD in either parent. The sequencing of UCH- L l was solely performed by Dr M Fairer and Dr SJ Lincoln, Jacksonville, (see

appendix 4). I was responsible for the clinical collection of seven of the eleven families. Disease segregation within each family was compatible with autosomal dominant transmission. The second study involved sequencing an index case from an affected sibling pair which had been collected as part of the GSPD study. Not all families could be sequenced for UCH-Ll due to resource and time restrictions, therefore the above analysis at 4pl4-16.1 was performed by myself to ensure that before UCH-Ll was sequenced in an affected case, segregation of a shared affected haplotype at PARK 4 and a marker linked to UCH-Ll was present in both affecteds from each individual family. UK 401 was screened for mutations in UCH-Ll before it was sequenced for Parkin. The clinical characteristics of all families are described below and the

sequencing results briefly summarised for discussion purposes. Appendix 4.1 includes a list of UK families in whom UCH-Ll was sequenced.

4.7.2 Sequencing study of UCH-Ll in an index case from 13 autosomal dominant PD families (study 1)

The clinical details of the eleven families with 3 or more affecteds and a history of PD in either parent are described below.None of these families had a mutation within the

SNCA (Fairer et al., 1998, Vaughan et a/.,1998a). UK families are coded in a standard

Family 3 (Lincoln et a l, 1999)

This family, of English/Irish descent, had 21 individuals in five generations affected with parkinsonism. Age of onset ranged from the third to the fifth decade, and was typically that of rigidity of a limb and/or resting tremor. L-dopa-responsiveness was usually excellent for approximately five years, after which severe "on/off fluctuations, dyskinesias, autonomic dysfunction, and marked gait freezing developed. Cognitive

dysfunctionwas variable. Lewy bodies in the substantia nigra were confirmed on

autopsy in an affected member.

Family 4 (Lincoln et a l, 1999)

The family was of African-American origin, and affected individuals include a brother and sister who developed parkinsonism in their 50s. The disease began in most individuals with resting tremor in an upper extremity and subsequent insidious progression of parkinsonism, including increasing bradykinesia and gait difficulty. Although L-dopa therapy was initially beneficial, dyskinesias developed after about 7 years.

Family UK 301

Members of this family presented with a L-dopa-responsive parkinsonian syndrome between the ages of 19 and 71 with age of onset lower in successive generations. All individuals presented with unilateral resting tremor of an upper extremity, with subsequent rapid progression to bilateral involvement. Subjects in later generations developed early dysarthria and upper limb rigidity in addition to the resting tremor.

UK 401

This kindred of Irish descent has 5 out of 10 siblings who developed L-dopa-responsive parkinsonian syndrome in the third and fourth decade. The index case presented with a stiff left leg at 32 years. He then became rapidly bradykinetic and suffered falls

secondary to poor balance. F-dopa PET studies on the proband revealed profound impairment of F-dopa re-uptake in the striatum.

UK 003

A total of 6 affected members, of Welsh descent, developed a parkinsonian syndrome

responsive to L-dopa between 50 and 63 years of age. At onset the common presenting symptom was a unilateral resting tremor. Progression of the syndrome was

characterised by increasing gait difficulty and later falls.

UK 402 (see section 5.3.2)

16 of 32 members of this English family developed a L-dopa-responsive parkinsonian syndrome. Age of onset ranged from 42-70 years. The usual mode of presentation was that of asymmetrical resting tremor. Dyskinesias typically developed after 5-7 years. Severely affected members of the kindred had motor fluctuations and gait disturbance.

Family UK 062

A total of 4 affected members were characterised in this family. The presenting feature was micrographia with subsequent development of a complete L-dopa-responsive parkinsonian syndrome.

F amity UK 074

A total of 6 individuals in this English family were were affected. The parkinsonian

syndrome was L-dopa-responsive. Progression was characterised by motor fluctuations and severe gait difficulties.

Family UK 305

This family, of English descent included three of four additional siblings with essential tremor. A total of 3 affected individuals in this family had a L-dopa-responsive

parkinsonian syndrome.

Family M I (Lincoln et a l, 1999)

This family of English/Dutch descent had a typical age of onset between 50 and 70 years. Manifestations in five affected members included resting tremor, rigidity, and postural instability. Initially carbidopa/L-dopa had excellent results, but wearing off and dyskinesias developed around eight years later. Three individuals separately suffered from essential tremor.

Family M N (Lincoln et ah, 1999)

This family, of Dutch/Norwegian descent, typically had an age of onset ranging from 60 to 75 years. A total of five individuals in two generations had PD. The findings on examination included resting tremor, micrographia, and later, gait difficulties. L-dopa responsiveness persisted throughout the typical course of 15 years, with some wearing off phenomena and dyskinesias. Dementia was not seen.

4.7.3 PARK4 analysis and sequencing study of UCH-Ll in an index case from 11 affected sibling pairs (study 2)

European Caucasian families with PD were included in the study. In all families at least 2 affected sibs in each family were present. PD was diagnosed using the rigorous criteria of idiopathic PD according to a similar study design as described elsewhere

(Maraganore et ah, 1991). All patients gave their informed consent according to the

declaration of Helsinki. As part of the ongoing total genome screen in families with PD, 96 affected families were tested for allele sharing on chromosome 4p by myself. The markers used to test for allele sharing on chromosome 4p were D4S230, D4S1609,

D4S391, D4S2397 and D4S405 (UCH-Ll), spanning 12.4cM telomeric to centromeric on the Genethon map.

4.7.4 Mutation analysis of UCH-Ll (study 1)

No mutations in the coding region of the UCH-Ll gene were found in 11 families with PD in which it was sequenced. However, one major coding polymorphism (S18Y) and several common, non-coding, promotor (-16(Y)/-24(R)) and intronic variants

(Ex2-i-6(Y) and +19(M)) were found in several affected individuals (these included one

Dutch and one Italian affected sibling) (Lincoln et aL, 1999). The frequency of the

S18Y allele was 23% from study 1, estimated from 110 individuals without documented movement disorder. It was lower in the small population of affected sibling pairs

screened (see study 2 below). This difference is probably a chance finding due to small sample size. The alternative explanation is that the observation is secondary to a genetic

background with different allele frequencies (Harhangi et aL, 1999).

4.7.5 Mutation analysis of UCH-Ll (study 2)

Twenty-nine out of 96 GSPD families showed a pattern of inheritance consistent with

autosomal dominant transmission (as in the original report (Leroy et aL, 1998)).

Mutation analysis (see appendix 2) was performed on an index case, by our collaborators at The Mayo Clinic, from those families in which 2 affected siblings shared a haplotype for all five markers (a total of 11 out of the remaining 29 families). The characteristics and country of origin of the individuals tested for mutations in UCH-Ll are listed in Table 4.13 for discussion purposes. In total 11 index cases were sequenced for mutations in UCH-Ll gene from GSPD affected sib pair families. In the

affected sibling pairs, the overall mean age at onset of PD was 55.2+1- 8.1 years with a

Table 4.13: Characteristics and origin of the individuals sequenced for the UCH-Ll gene

Origin No. of families Individuals

sequenced Mean age of onset years (SD) Mean duration of illness years (SD) French 4 4 57.0 (9.3) 12.8 (14.5) German 1 1 51.0 18.0 Italian 4 4 56.5 (7.3) 7.5 (5.8) Dutch 2 2 51.0(12.7) 10.5 (6.4)

4.8 DISCUSSION: GSPD COLLABORATIVE ANALYSIS OF THE SNCA, UCH-