The G6055A (G2019S) mutation in LRRK2 is frequent in both early and late onset Parkinson's disease and originates from a common ancestor

BACKGROUND

Mutations in the gene Leucine-Rich Repeat Kinase 2 (LRRK2) were recently identified as the cause of PARK8 linked autosomal dominant Parkinson's disease.

OBJECTIVE

To study recurrent LRRK2 mutations in a large sample of patients from Italy, including early (<50 years) and late onset familial and sporadic Parkinson's disease.

RESULTS

Among 629 probands, 13 (2.1%) were heterozygous carriers of the G2019S mutation. The mutation frequency was higher among familial (5.1%, 9/177) than among sporadic probands (0.9%, 4/452) (p<0.002), and highest among probands with one affected parent (8.7%, 6/69) (p<0.001). There was no difference in the frequency of the G2019S mutation in probands with early v late onset disease. Among 600 probands, one heterozygous R1441C but no R1441G or Y1699C mutations were detected. None of the four mutations was found in Italian controls. Haplotype analysis in families from five countries suggested that the G2019S mutation originated from a single ancient founder. The G2019S mutation was associated with the classical Parkinson's disease phenotype and a broad range of onset age (34 to 73 years).

CONCLUSIONS

G2019S is the most common genetic determinant of Parkinson's disease identified so far. It is especially frequent among cases with familial Parkinson's disease of both early and late onset, but less common among sporadic cases. These findings have important implications for diagnosis and genetic counselling in Parkinson's disease.

Natural history and clinical features of progressive supranuclear palsy: a clinical study

Progressive supranuclear palsy (PSP or Steele-Richardson-Olszewski syndrome) is one of the most-common types of atypical parkinsonism. To characterize the natural history and the clinical features of PSP, we reviewed the records of 25 patients followed in our clinic since 1991, with a clinical diagnosis of PSP according to NINDS and Golbe criteria. Progressive onset of early bilateral bradykinesia and postural instability with falls during the 5th decade strongly support the diagnosis of PSP in our patients. Pseudobulbar symptoms are very common at onset and during the course of the illness.

Efficacy and tolerability of dopamine agonists in a parkinsonian population

A clinical retrospective study was carried out in a population of 366 Parkinson's disease (PD) outpatients, to analyse the efficacy and tolerability of nonergoline and ergoline dopamine agonist (DA), in monotherapy or in combination with L-dopa. Safety was comparable in both groups except for higher occurrence of gastrointestinal symptoms in ergoline group and somnolence in nonergoline group. No significant difference concerning efficacy and tolerability was found during DA monotherapy. Mean age at PD onset was slightly higher in patients withdrawing DA monotherapy for adverse events comparing to patients who needed the addition of L-dopa (60.36 +/- 7.53 versus 54.88 +/- 10.75; p<0.05), suggesting that older age at the onset of the disease increases the risk for adverse events during DA monotherapy. The follow-up of the remaining patients still in monotherapy with DA will allow a better evaluation of these aspects.