PINK1-PD in Austronesian Population: Novel Mutation and Clinical Advantages of 7-Tesla MRI Versus DATSCAN-SPECT
Jaroslaw Dulski1, Erik Middlebrooks2, Zbigniew Wszolek1
1Department of Neurology, 2Department of Radiology, Mayo Clinic Florida
Objective:
To present a novel PINK1 mutation that may be characteristic of patients of Austronesian ancestry and the clinical advantages of 7-Tesla (T) MRI over DATSCAN-SPECT in neuroimaging of Parkinson’s disease (PD).
Background:
Most of the previous studies on the genetics of PD are pertinent to patients of European ancestry. Recently, a relatively high frequency of PD due to homozygous PINK1-PD p.Leu347Pro mutations was observed in patients of Austronesian ancestry, most likely due to the founder effect. However, as this region is understudied, other genetic variants may also be typical for Austronesian populations.
Design/Methods:
We present a case report of a patient of Filipino ancestry who developed early-onset PD (AOO: 38 years), of tremor-dominant subtype with symptoms more prominent on the right side, with neuropsychological features, slow progression, and good response to L-Dopa. The patient was assessed with DATSCAN SPECT, 3T and 7T brain MRI. Multigene genetic panel for PD was performed.
Results:
DATSCAN SPECT showed asymmetric tracer uptake, more affected in the right striatum. The 3T MRI was unrevealing. The 7T MRI demonstrated loss of neuromelanin signal and abnormal iron deposition, worse in the left substantia nigra. Genetic testing found PINK1 p.Leu347Pro and a novel PINK1 c.1252-1G>A (splicing variant). The latter mutation was indicated as pathogenic by in silico prediction models (CADD score of 34) and was not present in gnomAD.
Conclusions:
The patient is a compound heterozygote for the previously reported PINK1 p.Leu347Pro and the newly reported PINK1 c.1252-1G>A mutation. The former is characteristic of Austronesian populations; however, as the latter was not reported before, it may also be typical for this region. Findings on 7T MRI better correlated with clinical symptoms than DATSCAN-SPECT.