Exome Sequencing: Mutilating Sensory Neuropathy with Spastic Paraplegia due to a Mutation in FAM134B Gene

Table 1

Summary of the clinical and neurophysiological findings.

Individual as indicated in Figures 1(a) and 1(b)	Sex / Age	Silent Clinical Features	Motor Study	Sensory Study	Comment
Family 1: IV-1	F/10	Delayed walking, spastic gait, foot ulcers	Median nerve CMAP/AMP = 9.2 (N 8 mV); Median nerve CMAP/CV = 46 (N 45 m/s); Peroneal nerve CMAP/AMP = 3.3 (N 3.0 mV); Peroneal nerve CMAP/CV = 46 (N 42 m/s)	Median nerve SNAP/AMP = 10.2 (N 9.5 mV); Median nerve SNAP/CV = 55 (N 53 m/s); Sural nerve SNAP/AMP = 8.5 (N 6 mV); Sural nerve SNAP/CV = 45 (N 48 m/s)	Low normal; Normal autonomic studies (beat to beat variation and sympathetic skin response)
Family 1: IV-1; (Repeated study)	F/28	Multiple foot and leg ulcers with mutilating acropathy	Median nerve CMAP/AMP = 6.1 (N 8 mV); Median nerve CMAP/CV = 42 (N 45 m/s); Peroneal nerve CMAP/AMP = 2.5 (N 3.0 mV); Peroneal nerve CMAP/CV = 35 (N 42 m/s)	Median nerve SNAP/AMP = 3.0 (N 9.5 mV); Median nerve SNAP/CV = 45 (N 53 m/s); Sural nerve SNAP/AMP = 0.5 (N 6 mV); Sural nerve SNAP/CV = 37 (N 48 m/s)	Repeated study confirmed severe sensory axonal polyneuropathy in length dependent fashion
Family 1: IV-2	M/23	Delayed walking, spastic gait, repeated falls, foot and hand ulcers	Ulnar nerve CMAP/AMP = 6 (N 7 mV); Ulnar nerve CMAP/CV = 42 (N 45 m/s); Peroneal nerve CMAP/AMP = 3.2 (N 3.0 mV); Peroneal nerve CMAP/CV = 46 (N 42 m/s)	Ulnar nerve SNAP/AMP = 2.1 (N 9.5 mV); Ulnar nerve SNAP/CV = 46 (N 55 m/s); Sural nerve SNAP/AMP = absent (N 6 mV); Sural nerve SNAP/CV = absent (N 48 m/s)	Axonal sensory more than motor polyneuropathy
Family 2: IV-1	M/10	Repeated falls, spastic gait and multiple foot ulcers started at age 5	Median nerve CMAP/AMP = 10.2 (N 8 mV); Median nerve CMAP/CV = 55 (N 45 m/s); Peroneal nerve CMAP/AMP = 3.2 (N 3.0 mV); Peroneal nerve CMAP/CV = 47 (N 42 m/s)	Median nerve SNAP/AMP = 9.4 (N 9.5 mV); Median nerve SNAP/CV = 55 (N 53 m/s); Sural nerve SNAP/AMP = 7.5 (N 6 mV); Sural nerve SNAP/CV = 50 (N 48 m/s)	Low normal; Normal autonomic studies (beat to beat variation and sympathetic skin response)

CMAP = compound muscle action potential; AMP = amplitude; CV = conduction velocity; SNAP = sensory nerve action potential; mV = millivolt; μV = microvolt; m/s = meter per second.