A Novel Mutation of Gene in a Patient with Early-onset Parkinson's Disease.

Between 3-5% of all patients with Parkinson's disease (PD) have onset before the age of 40 years, which is likely related to genetic causes. Parkin gene mutations are the most common mutations, which are associated with autosomal recessive early-onset PD. 
A 34-year-old Emirati female presented with complaints of limb and speech tremor. She had been having difficulties in initiating movement and speech during her job. These problems began two years ago and had become progressively worsened. Her medical history was significant for generalized seizures for the past three years, which was well controlled with prescription medications. She was unaware of any family members with Parkinson's or any genetic disorders. Her examination revealed a reduction in eyelid blinking movement and hypomimia facial appearance. She had severe bilateral upper and lower extremity rigidity, which was more evident on her right side. While resting, the patient exhibited bilateral pin-rolling tremors in both of her upper extremities. Her gait was shuffling in nature with reduced arm swing and abnormal retropulsion. All of her laboratory investigations were normal. Genetic analysis revealed a homozygous 1 base pair insertion in exon 5 of gene (c.601_602insA), resulting in a nonsense mutation causing a stop codon instead of a cysteine codon (p. Cys201X). The patient showed an excellent response to treatment. We described a case of early-onset PD in a female, who on genetic analysis, was found to have a previously undescribed homozygous mutation in the gene.