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Table 3 Electrophysiology and MRI findings

From: Autosomal recessive spastic ataxia of Charlevoix Saguenay (ARSACS): expanding the genetic, clinical and imaging spectrum

family No.

SACS variants

Sensory nerve conduction sural or radial nerve

Motor nerve conduction tibial or ulnar nerve

Motor evoked potentials

Cerebellar atrophy

Arachnoid cyst posterior fossa

T2 hypo-intensities pons

T2 hyper-intensities lateral pons/MCP

Thickening of MCP

Bilateral parietal atrophy

Thin corpus callosum (MRI)

patients with 2 likely pathogenic SACS variants

           

#1

p.[Leu3102Phefs*8];[Leu3102Phefs*8]

Sur: no SNAP Rad: no SNAP

Tib:reduced CMAP+MNCV Uln: reduced MNCV

prolonged UE+LE

+, vermal

+

+

+

+

+

+

#2

p.[Arg728*];[Phe4352Leufs*11]

Sur: no SNAP Rad: no SNAP

Tib: reduced MNCV Uln: reduced MNCV

prologned UE, not evoked LE

+, pancerebellar

+

+

+

+

+

+

#3

p.[Gly1257*];[Lys2862*]

Sur: no SNAP Rad: no SNAP

Tib: no MSAP Uln: reduced MNCV

prolonged UE, not evoked LE

+, pancerebellar

+

+

+

+

+

+

#4

p.[Ile3848del];[Ile3848del]

Sur: no SNAP Rad: reduced CMAP+SNCV

Tib: reduced MNCV Uln: reduced MNCV

prolonged UE, not evoked LE

-, only asymmetry of cerebellar hemispheres

+

+

+

+

-

+

#5

p.[Leu796Tyrfs*13];[L3995dup]

Sur: no SNAP Rad: reduced CMAP+SNCV

Tib: reduced CMAP+MNCV Uln: reduced MNCV

prolonged UE, not evoked LE

+, vermal

+

+

+

+

-

+

#6

p.[Arg3875His]; [Leu549_Leu552del]; [Ser4513Asn]

Sur: reduced CMAP+SNCV Rad: reduced CMAP+SNCV

Tib: reduced CMAP+MNCV Uln: reduced MNCV

prolonged UE, not evoked LE

+, vermal

+

+

+

+

+

-

#7

p.[Val1849Serfs*48]; [Tyr4201*]

Sur: reduced CMAP+SNCV

Tib: reduced CMAP+MNCV

not evoked LE

+, pancerebellar

n.a.

n.a.

n.a.

n.a.

n.a.

n.a.

#8

p.[Arg2426Pro]; [Tyr2975Phefs*29]

Sur: normal

Tib: normal

not done

+, vermal

-

+

+

+

-

-

#9

p.[Gln1652*]; [Gln1709*]

Sur: no SNAP Rad: reduced SNAP+SNCV

Tib: reduced CMAP+MNCV Uln: reduced MNCV

not evoked LE

+, pancerebellar

-

+

+

+

+

-

patients with 2 SACS variants of unknown significance

           

#10

p.[Thr458Ile]; [Thr458Ile]

Sur: normal

Tib: normal

normal UE+LE

slight vermal atrophy, herniation of tonsils

+

-

-

-

-

+

#11

p.[Thr458Ile]; [Val995Phe]

Sur: red SNAP Rad: red SNAP

Tib: red CMAP

prolonged UE+LE

+, pancerebellar

-

-

-

-

+

+

  1. Sur=sural; rad= radial; Tib= tibial, Uln=ulnar; SNAP=sensory nerve action potential; SNCV=sensory nerve conduction velocity; CMAP=compound muscle action potential; MNCV=motor nerve conduction velocity; UE=upper extremity, LE= lower extremity; MCP=middle cerebellar peduncles; n.a.= not available.