Mitochondrial Diabetes is Associated with tRNA^Leu(UUR) A3243G and ND6 T14502C Mutations

Figures & data

Figure 1 Two Han Chinese pedigrees with maternally transmitted T2DM, arrows indicate the probands.

Table 1 Clinical and Molecular Characterizations of Some Members in Two Chinese Pedigrees with T2DM

Subjects	Gender	BMI (kg/m^2)	Age at Onset (Year)	Age at Test (Year)	Fasting Glucose (mmol/L)	Fasting Insulin (μU/ mL)	HOMA-IR	HbA1c (%)	Ketoacidosis	Visual Acuity Right/Left Eye	Level of Vision Loss	PTA (dB) Right/Left Ear	Level of Hearing Loss	Clinical Presentations	Functional mtDNA Mutations
DM1: II-1	Female	25.5	51	55	16.3	13.2	9.56	7.6	No	0.5/0.4	Normal	24/24	Normal	T2DM; IR	m.A3243G
DM1: II-10	Male	26.4	58	61	15.0	11.1	7.4	6.9	No	0.2/0.1	Mild	55/30	Moderate	T2DM; IR; myopia; hearing loss	m.A3243G
DM1: III-7	Female	27.0	36	38	8.80	16.8	6.57	7.4	Yes	0.4/0.3	Normal	20/25	Normal	T2DM; IR	m.A3243G
DM2: II-2	Male	23.5	60	68	8.14	6.9	2.49	7.2	No	0.1/0.1	Moderate	90/100	Profound	T2DM; myopia; hearing loss	m.A3243G and m.T14502C
DM2: II-4	Male	27.8	62	70	7.95	17.9	6.32	7.0	No	0.05/0.05	Severe	90/90	Profound	T2DM; IR; myopia; hearing loss	m.A3243G and m.T14502C
DM2: III-4	Male	28.5	39	39	7.21	11.0	3.52	6.8	Yes	0.2/0.2	Mild	60/70	Severe	T2DM; IR; myopia; hearing loss	m.A3243G and m.T14502C
DM2: III-6	Male	26.0	40	41	7.33	10.5	3.42	6.6	Yes	0.1/0.2	Moderate	85/80	Severe	T2DM; IR; myopia; hearing loss	m.A3243G and m.T14502C
DM1: III-1	Female	21.3	/	30	5.5	6.6	1.61	5.0	No	0.5/0.5	Normal	20/16	Normal	Normal	None
DM1: III-2	Female	22.8	/	28	5.2	5.4	1.25	5.3	No	0.6/0.8	Normal	17/21	Normal	Normal	None
DM1: III-3	Male	23.5	/	29	5.0	7.0	1.55	5.7	No	0.6/0.6	Normal	15/15	Normal	Normal	None

Abbreviations: BMI, body mass index; HOMA-IR, homeostasis model assessment of insulin resistance; PTA, pure-tone audiometry; dB, decibel; T2DM, type 2 diabetes mellitus; IR, insulin resistance.

Table 2 mtDNA Variants in Two Pedigrees with T2DM

Gene	Position	Sequence Variant	Amino Acid Change	Conservation (H/B/M/X)^a	DM1	DM2	rCRS^b	Previously Reported^c
D-loop	73	A to G			G	G	A	Yes
	146	T to C			C		T	Yes
	195	T to C			C	C	T	Yes
	310	T to CTC			CTC		T	Yes
	524	delC				delC	C	Yes
	16,051	A to G			G	G	A	Yes
	16,111	C to T				T	C	Yes
	16,182	A to C			C		A	Yes
	16,189	T to C			C	C	T	Yes
	16,274	G to A			A	A	G	Yes
	16,311	T to C			C		T	Yes
	16,519	T to C			C	C	T	Yes
	16,569	T to C				C	T	Yes
12S rRNA	709	G to A		G/G/A/-	A		G	Yes
	750	A to G		A/A/A/-	G	G	A	Yes
	1041	T to C		A/T/T/T		C	T	Yes
	1438	A to G		A/A/A/G	G	G	A	Yes
16S rRNA	2706	A to G		A/G/A/A	G	G	A	Yes
	3107	delN			delN	delN	N	Yes
tRNA^Leu(UUR)	3243	A to G		A/A/A/A	G	G	A	Yes
ND1	3483	G to A				A	G	Yes
	3970	C to T				T	C	Yes
	4071	C to T			T		C	Yes
	4161	C to T				T	C	Yes
ND2	4491	G to A	Val to Ile	V/I/I/V	A	A	G	Yes
	4769	A to G			G	G	A	Yes
	4883	C to T				T	C	Yes
	4895	A to G			G		A	Yes
CO1	6392	T to C				C	T	Yes
	7028	C to T			T	T	C	Yes
CO2	7785	T to C			C		T	Yes
	8020	G to A			A		G	Yes
NC7	8271–79	del 9-bp				9-bp del	9-bp	Yes
A8	8414	C to T	Leu to Phe	L/F/M/W	T		C	Yes
A6	8584	G to A	Ala to Thr	A/V/V/I	A	A	G	Yes
	8701	A to G	Thr to Ala	T/S/L/Q	G	G	A	Yes
	8856	G to A				A	G	Yes
	8860	A to G	Thr to Ala	T/A/A/T	G		A	Yes
CO3	9540	T to C			C		T	Yes
	10,136	A to G				G	A	Yes
ND4	10,873	T to C				C	T	Yes
	11,719	G to A			A	A	G	Yes
	12,091	T to C				C	T	Yes
ND5	12,361	A to G				G	A	Yes
	12,705	C to T			T	T	C	Yes
	13,401	T to C			C		T	Yes
	13,563	A to G				G	A	Yes
ND6	14,256	T to C	Ile to Val	I/M/I/V	C		T	Yes
	14,502	T to C	Ile to Val	I/I/I/I		C	T	Yes
Cytb	14,766	C to T	Thr to Ile	T/S/T/S	T	T	C	Yes
	14,783	T to C			C	C	T	Yes
	15,043	G to A			A		G	Yes
	15,301	G to A			A	A	G	Yes
	15,326	A to G	Thr to Ala	T/M/I/I	G	G	A	Yes
	15,346	G to A			A		G	Yes
	15,784	T to C			C		T	Yes
	15,850	T to C				C	T	Yes

Notes: ^aConservation of amino acid for polypeptides or nucleotide for RNAs in human (H), bovine (B), mouse (M), and Xenopus laevis (X). ^brCRS: reversed Cambridge Reference Sequence. ^cSee online mitochondrial genome databases http://www.mitomap.org.

Figure 2 Identification of tRNA^Leu(UUR) A3243G and ND6 T14502C mutations by direct sequencing.

Abbreviations: WT, wild type; MT, mutant.

Figure 3 Analysis of ATP levels in three patients with the m.A3243G and m.T14502C mutations, three patients with the only m.A3243G mutation and three controls without these mtDNA mutations.

Figure 4 Analysis of ROS production in three patients with the m.A3243G and m.T14502C mutations, three patients with the only m.A3243G mutation and three controls without these mtDNA mutations.

Table 3 Summary of Clinical and Molecular Data for 19 DM Pedigrees Carrying tRNA^Leu(UUR) A3243G Mutation

Family Number	Country	Number of Matrilineal Relatives	Number of Affected Relatives	Penetrance of DM (%)	Other Functional mtDNA Mutations	References
1	China	11	3	27.2	None	This study
2	China	10	4	40	ND6 T14502C mutation	This study
3	Italy	9	3	33.3	10.4-kb deletion	[61]
4	Tunisia	9	5	55.5	1.0-kb deletion	[62]
5	Taiwan	5	1	20	None	[63]
6	Taiwan	18	6	33.3	None	[64]
7	China	9	3	33.3	None	[65]
8	USA	11	3	27.2	None	[66]
9	USA	13	4	30.7	None	[67]
10	Japan	10	3	30	None	[68]
11	Japan	5	2	40	None	[69]
12	Japan	11	2	18.2	None	[70]
13	Sweden	23	6	26.1	None	[71]
14	Sweden	22	6	27.2	None	[72]
15	Netherlands	25	11	44	None	[73]
16	Portugal	11	3	27.2	None	[74]
17	Switzerland	16	6	37.5	None	[75]
18	Norway	38	7	18.4	None	[76]
19	Germany	7	2	28.6	None	[77]

Abbreviations: DM, diabetes mellitus; mtDNA, mitochondrial DNA.

Table 4 Overview of Clinical Presentation of Mitochondrial ND6 T14502C Mutation

Number	Age	Gender	Clinical Features	Family History	References
1	17	Female	LHON	Yes	[78]
2	4	Male	LHON	Yes	[78]
3	40	Female	LHON	Yes	[78]
4	30	Male	LHON	Yes	[79]
5	38	Female	LHON	Yes	[80]
6	24	Male	LHON	Yes	[80]
7	26	Female	LHON	Yes	[80]
8	19	Male	LHON	Yes	[80]
9	32	Female	LHON	Yes	[81]
10	43	Male	Hypertrophic Cardiomyopathy	No	[82]

Abbreviation: LHON, Leber’s hereditary optic neuropathy.

Rigoli L, Salpietro DC, Caruso RA, et al. Mitochondrial DNA mutation at np 3243 in a family with maternally inherited diabetes mellitus. Acta Diabetol. 1999;36(3):163–167. doi:10.1007/s005920050161

 Web of Science ®Google Scholar

Tabebi M, Safi W, Felhi R, et al. The first concurrent detection of mitochondrial DNA m.3243A>G mutation, deletion, and depletion in a family with mitochondrial diabetes. Mol Genet Genomic Med. 2020;8(7):e1292. doi:10.1002/mgg3.1292

 PubMed Web of Science ®Google Scholar

Chen YN, Liou CW, Huang CC, et al. Maternally inherited diabetes and deafness (MIDD) syndrome: a clinical and molecular genetic study of a Taiwanese family. Chang Gung Med J. 2004;27(1):66–73.

 Google Scholar

Lien LM, Lee HC, Wang KL, et al. Involvement of nervous system in maternally inherited diabetes and deafness (MIDD) with the A3243G mutation of mitochondrial DNA. Acta Neurol Scand. 2001;103(3):159–165. doi:10.1034/j.1600-0404.2001.103003159.x

 Web of Science ®Google Scholar

Lu J, Wang D, Li R, et al. Maternally transmitted diabetes mellitus associated with the mitochondrial tRNA(Leu(UUR)) A3243G mutation in a four-generation Han Chinese family. Biochem Biophys Res Commun. 2006;348(1):115–119. doi:10.1016/j.bbrc.2006.07.010

 PubMed Web of Science ®Google Scholar

Harrison TJ, Boles RG, Johnson DR, et al. Macular pattern retinal dystrophy, adult-onset diabetes, and deafness: a family study of A3243G mitochondrial heteroplasmy. Am J Ophthalmol. 1997;124(2):217–221. doi:10.1016/s0002-9394(14)70787-1

 PubMed Web of Science ®Google Scholar

Vivero RJ, Ouyang X, Kim YG, et al. Audiologic and genetic features of the A3243G mtDNA mutation. Genet Test Mol Biomarkers. 2013;17(5):383–389. doi:10.1089/gtmb.2012.0403

 Web of Science ®Google Scholar

Fukao T, Kondo M, Yamamoto T, et al. Comparison of mitochondrial A3243G mutation loads in easily accessible samples from a family with maternally inherited diabetes and deafness. Mol Med Rep. 2009;2(1):69–72. doi:10.3892/mmr_00000063

 PubMed Web of Science ®Google Scholar

Hotta O, Inoue CN, Miyabayashi S, et al. Clinical and pathologic features of focal segmental glomerulosclerosis with mitochondrial tRNALeu(UUR) gene mutation. Kidney Int. 2001;59(4):1236–1243. doi:10.1046/j.1523-1755.2001.0590041236.x

 Web of Science ®Google Scholar

Morovvati S, Nakagawa M, Sato Y, et al. Phenotypes and mitochondrial DNA substitutions in families with A3243G mutation. Acta Neurol Scand. 2002;106(2):104–108. doi:10.1034/j.1600-0404.2002.01172.x

 Web of Science ®Google Scholar

Cervin C, Liljeström B, Tuomi T, et al. Cosegregation of MIDD and MODY in a pedigree: functional and clinical consequences. Diabetes. 2004;53(7):1894–1899. doi:10.2337/diabetes.53.7.1894

 Web of Science ®Google Scholar

Lehto M, Wipemo C, Ivarsson SA, et al. High frequency of mutations in MODY and mitochondrial genes in Scandinavian patients with familial early-onset diabetes. Diabetologia. 1999;42(9):1131–1137. doi:10.1007/s001250051281

 Web of Science ®Google Scholar

van den Ouweland JM, Lemkes HH, Ruitenbeek W, et al. Mutation in mitochondrial tRNA(Leu)(UUR) gene in a large pedigree with maternally transmitted type II diabetes mellitus and deafness. Nat Genet. 1992;1(5):368–371. doi:10.1038/ng0892-368

 PubMed Web of Science ®Google Scholar

Alves D, Calmeiro ME, Macário C, et al. Family phenotypic heterogeneity caused by mitochondrial DNA mutation A3243G. Acta Med Port. 2017;30(7–8):581–585. doi:10.20344/amp.8638

 Web of Science ®Google Scholar

Gerber B, Manser C, Wiesli P, et al. A family with diabetes and heart failure. BMJ Case Rep. 2010;2010:bcr0120102613. doi:10.1136/bcr.01.2010.2613

 Google Scholar

Akbari M, Skjelbred C, Følling I, et al. A gel electrophoresis method for detection of mitochondrial DNA mutation (3243 tRNA(Leu (UUR))) applied to a Norwegian family with diabetes mellitus and hearing loss. Scand J Clin Lab Invest. 2004;64(2):86–92. doi:10.1080/00365510410004209

 Web of Science ®Google Scholar

Thorns C, Widjaja A, Boeck N, et al. Maternally-inherited diabetes and deafness: report of two affected German families with the A3243G mitochondrial DNA mutation. Exp Clin Endocrinol Diabetes. 1998;106(5):384–388. doi:10.1055/s-0029-1212003

 Web of Science ®Google Scholar

Zhao F, Guan M, Zhou X, et al. Leber’s hereditary optic neuropathy is associated with mitochondrial ND6 T14502C mutation. Biochem Biophys Res Commun. 2009;389(3):466–472. doi:10.1016/j.bbrc.2009.08.168

 PubMed Web of Science ®Google Scholar

Zhang S, Wang L, Hao Y, et al. T14484C and T14502C in the mitochondrial ND6 gene are associated with Leber’s hereditary optic neuropathy in a Chinese family. Mitochondrion. 2008;8(3):205–210. doi:10.1016/j.mito.2008.02.003

 PubMed Web of Science ®Google Scholar

Zhang J, Zhou X, Zhou J, et al. Mitochondrial ND6 T14502C variant may modulate the phenotypic expression of LHON-associated G11778A mutation in four Chinese families. Biochem Biophys Res Commun. 2010;399(4):647–653. doi:10.1016/j.bbrc.2010.07.135

 PubMed Web of Science ®Google Scholar

Vandeputte J, Van Heetvelde M, Van Cauwenbergh C, et al. Mild Leber hereditary optic neuropathy (LHON) in a Western European family due to the rare Asian m.14502T>C variant in the MT-ND6 gene. Ophthalmic Genet. 2021;42(4):440–445. doi:10.1080/13816810.2021.1913611

 PubMed Web of Science ®Google Scholar

Ozawa T, Tanaka M, Sugiyama S, et al. Patients with idiopathic cardiomyopathy belong to the same mitochondrial DNA gene family of Parkinson’s disease and mitochondrial encephalomyopathy. Biochem Biophys Res Commun. 1991;177(1):518–525. doi:10.1016/0006-291x(91)92014-b

 PubMed Web of Science ®Google Scholar