The instability of the BTB-KELCH protein Gigaxonin causes Giant Axonal Neuropathy and constitutes a new penetrant and specific diagnostic test

Table 1 Phenotypic data of patients

	F23	F24	F26	F27	F28	F29	F30
Country of origin	India	USA	USA	New Zealand	Northern Europe	Portugal	North Africa
Consanguinity	-	-	na	-	-	Same village	1 st
Gender	F	F	M	M	F	F	F
Onset (year)	4	2,5	2	3	2	11	4
Present age	10	9	10	22	7	38	20*
Muscle weakness/tone	+	+	+	+	+	+	+
Reduced MNCV^a	+	+	+	+	na	+	+
Loss of independence (year) or	8	3	3	10	na	-	na
Total loss of ambulation (year)	sa	sa	8	18	7	sa	8
Reduction of sensibility^b	S, D	S, D	S, D	S, D	S, D	S, D	S, D
Areflexia (lower limbs)	+	+	+	+	-	+	+
Vision^c	O, N	N	O, N	N	N	Normal	N
Dysarthria	+	+	+	-	+	-	+
Ataxia	+	+	+	-	+	-	+
Kinky hairs	+	+	+	-	+	-	+
Giant axon & NF aggregation	+	+	+	ni	ni	+	+
Suspicion of GAN	Severe	Severe	Severe	Mild	Severe	Mild	Severe
GAN mutation	c.724C > T	c.10-11del	c.146C > A	c.[971C > T]; [1391G > A]	-	-	C.994G > A
(Figure 2)	R242X		A49E	A324V/C464Y			G332R

*Deceased; na, not available; sa, still ambulant; ni, not investigated; -, absence.
1^st degree of consanguinity means that parents are first cousins.
^aMNCV, motor nerve conduction velocity; ^bS: Superficial sensitivity (light, touch temperature…); D: deep sensitivity (vibration, space…); ^cO: optic atrophy; N: nystagmus.
The clinical presentation of patients F23-F27 is further detailed in Roth et al., [22].

ISSN: 2051-5960