Background: Several studies have shown that 13 to 33% of patients with Parkinson's disease (PD) exhibit a positive familial history. The goals of this work were to identify patients with familial PD and to analyse whether there existed distinctive features between familial and sporadic cases.
Patients and method: 402 patients with PD from the Hospital Clínic i Universitari of Barcelona were evaluated prospectively. Clinical assessment was done using different scales in 169 patients. The disease was classified as tremorigenic, rigid or mixed according to the predominant symptoms.
Results: The frequency of familial PD was 13%. The age at onset was not different between familial and sporadic cases but it was significantly higher in females (57.4 [13] years) than in males (54.8 [11.4] years) (p < 0.05). The tremorigenic type of PD was more common in familial cases (35.5%) (p < 0.05). In familial PD cases, the age at onset was lower in descendents (53 [13] years) than in parents (68 [7.8] years) (p = 0.001).
Conclusions: Genetic factors may play an important role in the development of PD and gender-associated factors may modulate the age at onset. Familial PD cases differ from sporadic cases in the higher frequency of predominantly tremorigenic forms. The lower age at onset in descendents than in parents suggests the existence of a genetic anticipation phenomenon in familial PD.