Table 2.

Summary of the main clinical features in individuals with POLR3-related disorders

	POLR3A+POLR3B [5, 10, 12, 17, 21]	POLR1C [18]	POLR3K [20]	POLR3GL
Number of individuals	n = 147	n = 8	n = 2	n = 3
Intellectual disability	13/42	6/8	2/2	0/3
Motor delay	58/116	7/8	2/2	3/3
Cerebellar signs (ataxia, dysmetria)	142/147	8/8	8/8	0/3
Endosteal hyperostosis	U	U	U	3/3
Myopia	87/121	3/8	1/1	0/3
Oligo-/hypodontia	86/131	3/8	1/2	3/3
Hypogonadotropic hypogonadism/Delayed puberty	53/69	0/2	1/2	2/3
Short stature	54/126	U	2/2	3/3
Diffuse white matter abnormalities/Hypomyelination	100/126	8/8	2/2	U

U unknown

Not all phenotypic characteristics have been explicitly specified or examined for each of the individuals described in literature and this may lead to an under- or over appreciation of some phenotypic characteristics in the spectrum of POLR3-related disorders. The clinical presentation of cohorts of individuals with POLR3A and POLR3B variants are frequently discussed together in literature and therefore the data for these two genes are merged in the table. More detailed information can be found in Table S1