Table 1.

Clinical, neurophysiological, pathological and genetic features in our series (n=5)

Patient	1	2	3	4	5
Sex/age (years)	F/40	M/34	F/15	M/53	M/76
NEFL mutation	N98S	N98S	N98S	P8R	L311P
Inheritance*	De novo	De novo	De novo	n/a	n/a
Ethnicity	British	British/Irish	Austrian/Russian	British	British
Age of onset	<1 year	<1 year	<2 years	Second decade	Sixth decade
Initial symptoms	Delayed motor milestones, finger contractures	Delayed motor milestones, hypotonia	Delayed motor milestones, optic nerve hypoplasia	Unsteadygait, tremor in hands restless legs	Unsteady gait, tremor in hands
Muscle atrophy UL	Distal	Distal	Distal	Hands	Hands
Muscle atrophy LL	Distal and proximal	Distal and proximal	Distal	Distal	Distal
Muscle weakness UL	Hands 0–2, forearms 1–4, proximal 4–5	Hands 3, forearms 4–5	Hands 4–5	Hands 3–4	Hands 4–5
Muscle weakness LL	Distal 0, proximal 2–5	Distal 1, proximal 4–5	Distal 3–5	Distal 0–1	Distal 3–4
Deep tendon reflexes	Absent	Absent	Absent	Absent	Absent
Pinprick sensation	Reduced to mid-forearms/above knees	Reduced to mid-forearms/above knees	Normal	Reduced to wrists/knees	Reduced to above ankles
Vibration sense	Reduced to left shoulder/costal margins	Reduced to shoulders/sternum	Reduced to elbows/ankles	Reduced to elbows/costal margins	Reduced to the knees
Position sense	Reduced to the ankles	Reduced to the ankle and knee	Normal	Normal	Reduced to the ankles
Limb ataxia	UL/LL, marked, worse with eyes closed	UL/LL, mild, only with eyes closed	No	No	No
Pyramidal signs	No	No	No	No	No
Romberg’s test	Positive	Positive	Positive	Positive	Positive
Gait pattern	Steppage, ataxic	Steppage, proximal LL weakness	Steppage, ataxic	Steppage	Stamping, ataxic
Pes cavus	Yes	Yes	Yes	Yes	No
SNHL	Since age 5, hearing aids	Since age 8, hearing aids	Since age 8, hearing aids	Subclinical, high frequency	n/a
Other features	Dysarthria, mild head tremor, broken-up smooth pursuits, tongue hemiatrophy, mild scoliosis, scapular winging	Dysarthria, mild head tremor, broken-up smooth pursuits, scapular winging	Mild tremor in hands, muscle cramps, urinary incontinence	Mild head tremor, mild tremor in UL, mild broken-up smooth pursuits, RLS, PLMS	Mild head tremor tremor in hands, thickened ulnar nerves
NCS	Demyelinating neuropathy	Demyelinating neuropathy	Demyelinating neuropathy	Neuropathy with axonal and demyelinating features	Neuropathy with axonal and demyelinating features
CMTES	24	22	9	18	n/a
CSF protein (g/L)	n/a	0.55	n/a	0.39	0.76
BAEPs	Absent	Absent right, abnormal left	Absent	Normal	n/a
Brain MRI	Mild cerebellar and medullary volume loss	Normal	n/a	Normal	Normal
Spinal cord MRI	Mild cervical cord volume loss	Mild cervical cord volume loss	n/a	Normal	Normal
Nerve pathology	n/a	Loss or large myelinated fibres, irregularly shaped fibres, thin myelin sheaths, onion bulbs	n/a	Loss of large myelinated fibres, irregularly shaped fibres, regeneration clusters	n/a
Muscle pathology	Neurogenic changes	Neurogenic changes	n/a	n/a	n/a

^*Based on cosegregation analysis.

BAEPs, brainstem auditory evoked potentials; CMTES, Charcot-Marie-Tooth examination score; CK, plasma creatine kinase; distal, muscle groups below elbow/knee; F, female; LL, lower limbs; M, male; NCS, nerve conduction studies; PLMS, periodic limb movements disorder; proximal, muscle groups above elbow/knee; RLS, restless legs syndrome; SNHL, sensorineural hearing loss, UL = upper limbs