Juvenile-onset parkinsonism with pyramidal signs due to compound heterozygous mutations in the F-Box only protein 7 gene

Abstract

Background: Juvenile-onset parkinsonism is often caused by genetic factors. Mutations in several autosomal genes, including the F-box only protein 7 (FBXO7) gene, have been found in patients suffering from juvenile-onset parkinsonism with pyramidal signs. Only five types of FBXO7 mutations have been described. Here, we present a case report about a Chinese patient presenting with juvenile-onset parkinsonism likely caused by FBXO7 mutations.

Methods: The patient was a 32-year-old Chinese male. DNA samples were extracted from the patient and his parents. Exons in parkinsonism-related genes were amplified and sequenced.

Results: The patient began experiencing a progressive involuntary tremor in his left hand at 16 years of age, which was followed by the development of gait dysfunction, dysarthria, and rapid eye movement sleep behavior disorder. A neurological examination of the patient revealed cogwheel rigidity, bradykinesia, static and postural tremor and bilateral Babinski signs. The patient responded to dopaminergic therapies but was affected by psychiatric side effects. Further genetic analysis of the patient and his parents revealed compound heterozygous mutations of the FBXO7 gene (NM_012179.3) in the patient (a nonsense c.1408G > T (p.E470X) mutation and a missense c.152A > G (p.N51S) mutation coming from the patient's mother and father, respectively).

Conclusions: This is the first case harboring FBXO7 mutations that presented with juvenile-onset parkinsonism in the Chinese population.

Keywords: Chinese; FBXO7 gene; Juvenile-onset parkinsonism; PARK15.