Amyotrophic lateral sclerosis/frontotemporal dementia with predominant manifestations of obsessive–compulsive disorder associated to GGGGCC expansion of the c9orf72 gene

Abstract

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease involving upper and lower motor neurons. Up to 50 % of ALS cases have cognitive and/or behavioral impairment falling into the spectrum of frontotemporal dementia (FTD) [1]. Approximately 10 % of cases are familial (FALS), while the others are considered sporadic, as their occurrence seems to be random throughout the population. Recently, a GGGGCC hexanucleotide repeat expansion in the first intron of c9orf72 gene on chromosome 9p21 has been related to familial and sporadic cases with ALS, ALS-FTD, or FTD. [2–4]. We describe a 52-year-old man carrying the GGGGCC expansion in the c9orf72 gene. At 50, he developed muscle weakness and wasting at the right hand. Soon after he developed intrusive thoughts of urine loss, not supported by clinical evidence. After a pantoclastic episode characterized by aggressiveness towards objects and auditory hallucinations due to an obsessive impulse to urinary stimuli, he was admitted to our hospital. He had muscle weakness and atrophy of upper limbs (predominantly right) and spasticity of upper and lower limbs, hyperactive deep tendon reflexes, hyperactive jaw jerk, and fasciculations at limbs and trunk muscles. Bulbar and respiratory muscles were spared. Needle EMG showed a diffuse pattern of chronic and active denervation, with normal nerve conduction studies. Motor-evoked potentials demonstrated increased central motor conduction time. Psychiatric evaluation was consistent with obsessive–compulsive disorder (OCD) with predominantly Obsessional Thoughts or Rumination (ICD-10 code F42.0), with psychotic manifestations. The patient’s father died at 42 years old from spinal amyotrophic lateral sclerosis (ALS); he had no cognitive or behavioral impairment. The patient’s sister and a paternal uncle had a depressive disorder. The patient was found to carry a hexanucleotide repeat expansion in c9orf72 gene ([50 repeats); no other mutations of major ALS-FTD related genes were found. Magnetic resonance imaging (MRI) revealed bilateral reduction of fractional anisotropy along the corticospinal tract (predominantly right). Brain positron emission tomography (PET) with FDG presented reduced hypometabolism in the motor cortex bilaterally, in the fronto-mesial cortex bilaterally between the anterior and the middle cingulate gyrus (predominantly right) and in the postero-lateral occipital cortex bilaterally (Fig. 1). The neuropsychological assessment was consistent with a diagnosis of behavioral FTD, associated to OCD, hallucinations, and depressive mood disorder. In the following months, the patient developed dysarthria, dysphagia, tongue atrophy with fasciculations, lower limb weakness and hypotrophy, and worsening of spasticity at the upper and lower limbs. A. Calvo (&) C. Moglia A. Canosa A. Ilardi E. Bersano D. Bertuzzo A. Chio Department of Neuroscience, University of Turin, via Cherasco 15, 10126 Turin, Italy e-mail: andreacalvo@hotmail.com