PARK2 Microduplication: Clinical and Molecular Characterization of a Further Case and Review of the Literature

We report on a patient with psychomotor deficits, language delay, dyspraxia, skeletal anomalies, and facial dysmorphisms (hirsutism, right palpebral ptosis, a bulbous nasal tip with enlarged and anteverted nares, and a mild prominent antihelix stem). Using high-resolution SNP array analysis, we identified a 0.49-Mb microduplication in chromosome 6q26 inherited from the mother involving the PARK2 gene: arr[hg19] 6q26(162,672,821-163,163,143)×3 mat. To the best of our knowledge, this is the third patient to date described in whom a 6q26 microduplication encompassing only the PARK2 gene has been reported in medical literature. The PARK2 gene is a neurodevelopmental gene that was initially discovered as one of the causes of autosomal recessive juvenile Parkinson disease and subsequently reported to be linked to autism spectrum disorders and attention-deficit hyperactivity disorders. We provide an overview of the literature on PARK2 microduplications and further delineate the associated phenotype. Taken together, our findings confirm the involvement of this gene in neurodevelopmental disorders and are useful to strengthen the hypothesis that, although with variable expressivity and incomplete penetrance, the PARK2 microduplication is associated with a new emerging neurodevelopmental delay syndrome. However, clinical and molecular evaluations of more patients with the microduplication are needed for full delineation of this syndrome.