Co-occurrence of affective and schizophrenia spectrum disorders with PINK1 mutations

Objective

To investigate a possible association of mutations in the PTEN‐induced putative kinase 1 (PINK1) gene with psychiatric disorders in a large family with monogenic parkinsonism.

Method

20 members of a family (4 homozygous, 11 heterozygous and 5 non‐mutation carriers) were investigated for the presence of psychiatric disorders using the structured clinical interview for Diagnostic and Statistical Manual of Mental Disorders, 4^th edition (DSM‐IV); information on three additional heterozygous mutation carriers was obtained according to the family history research diagnostic criteria.

Results

We found predominantly affective and schizophrenia spectrum disorders in 11 (61%) of the 18 mutation carriers and in 1 (20%) of the 5 mutation‐negative cases.

Conclusions

First, affective and psychotic symptoms may be part of the phenotypic spectrum or even the sole manifestation of PINK1 mutations. Second, patients with familial movement disorders associated with psychiatric conditions may serve as a valuable study population to explore (genetic) causes of neuropsychiatric disease.In patients with Parkinson''s disease (PD), a wide range of psychiatric disorders has been described including depression (20–50%),¹ psychosis (15–40%),^2,3 anxiety disorder (20–40%) and cognitive impairment (20%).² Psychiatric disorders may be the first or even the only manifestation in carriers of Parkin gene mutations, the most‐frequent known cause of early‐onset parkinsonism (EOP).⁴ Likewise, psychiatric problems have been reported in patients and their motor‐asymptomatic relatives with mutations in the recently detected PTEN‐induced kinase 1 (PINK1) gene, the second‐commonest cause of EOP.^5,6,7,8,9Two homozygous mutations in the PINK1 gene were initially described in three consanguineous families with EOP.⁶ The frequency of PINK1 mutations ranges from 1% to 8% in patients with PD of different ethnicities who are often selected for young age of onset and for family history (for review see Klein and Schlossmacher¹⁰). Most of the currently described mutations are localised near or within the functional serine/threonine kinase domain of PINK1 and are expected to result in a loss‐of‐function effect in vivo. Wild‐type PINK1 functions as a protein kinase that is mainly located within the mitochondria.Although PINK1‐associated parkinsonism is generally considered an autosomal recessive condition, a growing body of evidence has been accumulating that supports the notion of a single heterozygous mutation conferring disease susceptibility in at least a subset of patients.^6,8,9,10,11Currently, no studies have systematically assessed psychiatric symptoms in monogenic EOP. To investigate this possible association, we evaluated a large family with EOP with PINK1 mutations for the presence of psychiatric disorders.