Table 1.

Genetic and Clinical Findings in Individuals with TRMT5 Variants

ID	Sex	TRMT5 Variantsa	OXPHOS Activities in Skeletal Muscle					Clinical Features
Respiratory-Chain Complex	Enzyme Activity	Absolute Values	Reference Range (Mean ± SD [range])	Histo-chemical COX Defect	Age at Onset	Clinical Course	Other Features
73901b	female	c.[312_315del;872G>A], p.[Ile105Serfs∗4;Arg291His]	I	59%	2.9	4.9 ± 0.9 (3.1–6.7)	>95% COX-deficient fibers	childhood	died at 55 years of age	life-long exercise intolerance, dyspnea, lactic acidosis, pancreatic disorder, spasticity/peripheral neuropathy, muscular weakness, renal tubulopathy, cirrhosis
II	138%	2.9	11.2 ± 2.7 (5.8 −16.6)
II+III	47%	5.3	2.1 ± 0.6 (0.9–3.4)
IV	36%	1.4	3.9 ± 1.3 (1.3–6.6)
65205c	male	c.[312_315del;1156A>G], p.[Ile105Serfs∗4;Met386Val]	I	32%	88	272 ± 115 (84–559)	none	birth	alive, 7 years old	premature delivery, failure to thrive, growth retardation, intestinal pseudo-obstruction, hypertrophic non-obstructive cardiomyopathy, muscular hypotonia, demyelinating neuropathy, global developmental delay, lactic acidosis
II	ND	ND	ND
II+III	136%	154	110 ± 70 (37–285)
IV	27%	315	1150 ± 400 (520–2080)

Abbreviation is as follows: ND, no data.

^acDNA (GenBank: NM_020810.3), protein (GenBank: NP_065861.3).

^bFor subject 73901, enzyme activities are expressed as percentage of control enzyme activity. Absolute values of residual enzyme activities are expressed as U/min/g wet weight, and the reference range (mean ± SD [range]) is shown for 46 control subjects.

^cFor subject 65205, percentages of residual enzyme activities are normalized to citrate synthase activity. Absolute values are expressed as mU/U citrate synthase activity, and the reference range is shown for 52 (complex I) and 27 (complex II+III and IV) control subjects.