Supplementary Table 1. FUS sequence variations not predicting aminoacid changes identified in ALS patients and/or controls

Nucleotide change / Patients / Controls
intronic / c.38+11delT / 1/338 / nt
c.190+32A>C / 1/338 / nt
c.335 -15delTTTT / 0/338 / 1/621
c.524-21T>C / 2/1009 / 2/793
c.833-29C>T
(rs72550862) / 1/338 / nt
c.1168+51A>C / 1/338 / nt
c.1542-8T>C / 0/1009 / 1/538
synonymous / c.153C>T
(rs61733962) / 1/338 / nt
c.675C>T / 0/1009 / 1/793
c.1464C>T / 2/1009 / 1/500
c.1566G>A / 8 /1009 / 5/538
3’UTR / c.*41G>A / 29/1009 / 17/538

Only rare variations (Minor Allele Frequency <0.05) are shown. Two further more common variations (rs741810 and rs1052352) were observed in ALS patients with a frequency similar to those reported in the Single Nucleotide Polymorphism database (dbSNP:

Numbering of FUS variants reflects cDNA numbering with +1 corresponding to the A of the ATG translation initiation codon in the GeneBank reference sequence NM_004960.2. The initiation codon is codon 1

nt: not tested

Supplementary Clinical Information

Patient 330

Patient 330 did not have a positive family history for motor neuron diseases. The proband developed unilateral scapular girdle and proximal upper limb muscle weakness at age 34, and in the subsequent few months (7 months) developed weakness of the controlateral upper girdle side and of the neck flexor/extensor muscles. He started to complain of fasciculations and cramps in the same regions. At the first examination, non bulbar involvement has been demonstrated but weakness of the neck flexor/extensor muscles. The proximal muscles of both arms showed symmetrical, marked atrophy and weakness. No pathological abnormalities could be detected distally in the hands and in the lower limbs. Reflexes were weak in the upper and brisk in the lower limbs (patellar normal, ankle jerk brisk).Motor and sensory nerve conduction studies were within normal range, while needle EMG showed fibrillation potentials and positive sharp waves in the infraspinatus, deltoid and brachial triceps bilaterally, as well as long-duration, high amplitude, polyphasic motor unit potentials in the upper limbs, sternocleidomastoideus, trapezious, and thoracic muscles. CK was slightly increased and CSF normal. TMS was normal and MRI of both the spinal cord and brain were normal (specifically, corticospinal tract (CST) hyperintensities on T2-weighted, proton density-weighted images were not found). Muscle biopsy has been performed with evidence of neurogenic atrophy. No cognitive defects were detected at neuropsychological tests. No further survival data are available.

Patient 1799

The proband is a 54-year-old Italian female with a probable family history of motor neuron disease (her mother died of a disease with similar features to ALS). She showed first clinical signs at the age of 51 with neck flexor-extensor muscles weakness, decreased strength of the scapular girdle and of the proximal upper limbs muscles; left side of the body was more seriously affected with remarkable atrophy signs. During the course of the disease the patient experienced progressive pelvic girdle muscles weakness with difficulty in the deambulation because of atrophy and severe proximal weakness of the lower left limb. No bulbar impairment neither pathological abnormalities distally in the hands or in the lower limbs were detected on ALS onset but after just an year she required a non invasive ventilatory support during night time that became continuative in the following six months. She developed also disphagia with rapid loss of weight. Tendon reflexes were weak in the upper limbs and brisk in the right lower one; no spasticity or extensor plantar response was observed bilaterally. EMG revealed neurogenic chronic signs with fibrillation and fasciculation potentials indicating an active denervation, more involving the proximal muscle of the left arm; no conduction blocks were detected. Brain MRI showed no abnormalities whereas cervical spinal cord imaging revealed bulging intervertebral disk at C5-C6 level. Lumbosacral TC revealed protrusions of discal material affected L4-L5 and L5-S1 levels. CSF and CPK were normal such as other routine parameters. No cognitive defects were detected at neuropsychological tests.