DOI : 10. 1111/ jn s. 12245 Journal of the Peripheral Nervous System 23:29–35 (2018)
Established and novel measures of upper limb
impairment in children with Charcot-Marie-tooth
disease type 1A and riboﬂavin transporter deﬁciency
Kayla M.D. Cornett
, Manoj P. Menezes
, Paula Bray
, Mark Halaki
, and Joshua Burns
Sydney Children’s Hospitals Network (Randwick and Westmead);
Faculty of Medicine and Sydney Children’s Hospital
Sydney Children’s Hospitals Network (Randwick and Westmead); and
Faculty of Health Sciences, The University of Sydney,
Sydney, New South Wales, Australia
Hand function is a problem in patients with Charcot-Marie-Tooth disease type
1A (CMT1A) and Riboﬂavin Transporter Deﬁciency type 2 (RTD2). However, a detailed
understanding of upper limb involvement in these conditions is lacking. The aim of this
pilot study was to compare hand and upper limb function between children with CMT1A,
RTD2 and healthy controls using established and novel outcome measures. Three age-and
sex-matched groups of four children (5–15 years, 1 male/group) with CMT1A, RTD2, and
healthy controls were assessed for function, strength, and sensation. Fatigue and muscle
activity of the FDI was also assessed using a submaximal contraction at 40% of the
participants’ maximal voluntary contraction. Functional measures were most affected in
children with RTD2 followed by children with CMT1A, compared to healthy controls.
Strength was similarly impaired in CMT1A and RTD2 compared to controls (p < 0.05).
Sensation was signiﬁcantly impaired in RTD2 compared to CMT1A and controls (p = 0.008).
While time to fatigue did not differ between groups, a decline in muscle activity while
force remained constant showed that controls compensated with other muscles during
the fatigue task while children with CMT1A and RTD2 did not have this compensatory
ability. Children with CMT1A and RTD2 exhibited marked hand/upper limb impairment.
These results suggest the upper limb should be a focus of rehabilitative therapy in affected
children using sensitive outcome measures of strength and sensation, as well as functional
activities of daily living, which are most relevant to the patient.
Key words: Charcot-Marie-Tooth disease, EMG, paediatric, riboﬂavin transporter deﬁciency
type 2upper limb, strength
Charcot-Marie-Tooth disease (CMT) is the most
common inherited peripheral neuropathy with CMT
Address correspondence to: Kayla M.D. Cornett, BHK, MSc,
Sydney Children’s Hospitals Network, The University of Syd-
ney, Locked Bag 4001, Westmead, New South Wales 2145,
Australia. Tel: +61-2-9845-3036; Fax: +61-2-9845-1317; E-mail:
type 1A (CMT1A), the most common form of CMT.
Hand weakness was recently reported to affect 42%
of children aged 3–20 years with CMT (Cornett et al.,
2016) but the extent of these are not known.
Riboﬂavin Transporter Deﬁciency type 2 (RTD2)
is a progressive neurodegenerative condition due to
defects in riboﬂavin transporter type 2 secondary to
mutations in the SLC52A2 gene. RTD2 is a gener-
alised sensory neuropathy with upper limb predomi-
nant motor neuropathy, auditory neuropathy, muscle
© 2017 Peripheral Nerve Society