The Association Between Mitochondrial tRNA^Glu Variants and Hearing Loss: A Case-Control Study

Figures & data

Figure 1 One Han Chinese family with NSHL, arrow indicated the proband.

Table 1 Molecular Characterization of Deafness-Associated Mt-tRNA^Glu Mutations

tRNA Species	Position	Alternation	Homoplasmy/Heteroplasmy	Location	Numbering in tRNA^Glu	CI (%)	Numbers of 180 Deaf Patients (%)	Numbers of 100 Controls (%)
tRNA^Glu	14,709	T to C	Heteroplasmy	Anticodon stem	37	100	2 (1.11)	0
tRNA^Glu	14,692	A to G	Homoplasmy	TψC loop	54	100	1 (0.56)	0
tRNA^Glu	14,693	A to G	Homoplasmy	TψC loop	55	100	4 (2.22)	0
tRNA^Glu	14,683	A to G	Homoplasmy	TψC loop	64	100	1 (0.56)	0

Abbreviation: CI, conservation index.

Figure 2 PCR amplification of mt-tRNA^Glu gene in subjects with NSHL, arrow indicated the PCR product, which was 1050-bp.

Figure 3 Sequence alignment of mt-tRNA^Glu gene from different species, arrows indicated the positions of 37, 54, 55 and 64, corresponding to the m.T14709C, m.A14693G, m.A14692G and m.A14683G variants.

Figure 4 Cloverleaf structure of mt-tRNA^Glu gene, arrows indicated the positions of m.T14709C, m.A14693G, m.A14692G and m.A14683G variants.

Table 2 Summary of Clinical and Molecular Data for Several Members of the Chinese Family

Subject	Gender	Audiometric Configuration	Age at Test (Year)	Age at Onset (Year)	Use of Aminoglycoside	PTA (dB) Right Ear	PTA (dB) Left Ear	Level of Hearing Loss
II-1	Male	Slope	78	69	No	103	99	Profound
II-6	Female	Rising	60	55	No	110	118	Profound
III-6	Female	Valley	30	28	No	40	35	Mild
IV-3	Female	Slope	2	1	No	105	116	Profound

Abbreviations: PTA, pure-tone audiometry; dB, decibels.

Figure 5 Audiological examination of matrilineal relatives of one pedigree with NSHL, (X) left ear; (O) right ear.

Table 3 mtDNA Variants in One Chinese Family with Hearing Impairment

Gene	Position	Nucleotide Change	Amino Acid Change	rCRS^a	Conservation (H/B/M/X)^b	Previously Reported^c
D-loop	73	A to G		A		Yes
	263	A to G		A		Yes
	310	T to TCC		T		Yes
	524	delC		C		Yes
	16,093	T to C		T		Yes
	16,189	T to C		T		Yes
	16,223	C to T		C		Yes
	16,519	T to C		T		Yes
12S rRNA	750	A to G		A	A/A/A/-	Yes
	1438	A to G		A	A/A/A/G	Yes
16S rRNA	2706	A to G		A	A/G/A/A	Yes
	3010	G to A		G	G/G/A/A	Yes
	3107	delN		N		Yes
ND1	3970	C to T		C		Yes
ND2	4769	A to G		A		Yes
	4833	C to T		C		Yes
	5178	C to A	Leu to Met	C	L/T/T/T	Yes
CO1	7028	C to T		C		Yes
CO1/tRNA^Ser(UCN)	7444	G to A	Ter to Lys	G	G/G/G/G	Yes
A6	8701	A to G	Thr to Ala	A	T/S/L/Q	Yes
	8860	A to G	Thr to Ala	A	T/A/A/T	Yes
CO3	9540	T to C		T		Yes
ND3	10,398	A to G	Thr to Ala	A	T/T/T/A	Yes
	10,400	C to T		C		Yes
ND4	11,719	G to A		G	G/G/G/G	Yes
	11,914	G to A		G		Yes
ND5	12,361	A to G		A		Yes
	12,705	C to T		C		Yes
ND6	14,668	C to T		C		Yes
tRNA^Glu	14,692	A to G		A	A/A/A/A	Yes
Cytb	14,766	C to T	Thr to Ile	C	T/S/T/S	Yes
	15,301	G to A		G		Yes
	15,326	A to G	Thr to Ala	A	T/M/I/I	Yes
	15,784	T to C		T		Yes

Notes: ^arCRS: revised Cambridge Reference Sequences. ^bConservation assessment in human, bovine, mouse and Xenopus laevis. ^cPlease see online databases: mitomap (www.mitomap.org) or mtDB (http://www.genpat.uu.se/mtDB).

Figure 6 Identification of m.A14692G and m.G7444A variants by direct sequencing analysis.

Figure 7 Location of deafness-associated variants in tRNA^Ser(UCN) and adjacent CO1. Arrow indicated the m.G7444A variant in the precursor of this tRNA and adjacent sequence of CO1 from wild-type (WT) and mutant (MT).

Figure 8 Analysis of mtDNA copy number in matrilineal relatives of the pedigree with NSHL. (A) mtDNA copy number; (B) ATP content; (C) ROS qualifications.

Data Sharing Statement

The datasets generated and/or analyzed during the current study are available from the corresponding author upon reasonable request (Yu Ding: [email protected]).