Table 2.

Salient features of subjects with GLRA2 variants

Subject	1	2	3	4	5	6	7	8	9	10	11	12	13
GLRA2 variant (hg19, NM_001118886.1)	c.887C>T, p.Thr296Met	c.887C>T, p.Thr296Met	c.887C>T, p.Thr296Met	c.887C>T, p.Thr296Met	c.887C>T, p.Thr296Met	c.887C>T, p.Thr296Met	c.140T>C, p.Phe47Ser	c.777C>G, p.Ile259Met	c.754C>T, p.Arg252Cys	c.862G>A, p.Ala288Thr	c.1186C>A, p.Pro396Thr	c.1199C>T, p.Pro400Leu	c.1334G>A, p.Arg445Gln
Inheritance	de novo	de novo	de novo	de novo	de novo	de novo	de novo	de novo	maternal	maternal	maternal	maternal	maternal
CADD score	27	27	27	27	27	27	27.8	23.4	31	27.2	20.9	22.3	33
Gender	female	female	female	female	female	female	female	female	male	male	male	male	male
Age at most recent evaluation (years)	6.7	6.5	5.5	0.5	5.4	0.8	6.7	5	0.9	7	34	15	5.9
Developmental delay/intellectual disability	yes	yes	yes	yes	yes	yes	yes	yes	yes	yes, with regression	yes	yes	yes
Hypotonia/incoordination	no	no	yes, ataxic gait	yes	no	no	no	yes, incoordination	yes	yes, ataxia	yes	no	yes, impaired fine motor coordination
Autism spectrum disorder	no	yes	no	NA	no	NA	no	no, diagnosis of child psychosis	NA	yes	yes	yes	suspected
Inattention/hyperactivity	yes	yes	no	NA	yes	NA	yes	no	NA	no	no	yes	yes
Sleep disturbance	no	yes	no	no	no	NA	yes	yes	yes	no	no	no	yes
Microcephaly	no	yes	yes	yes	yes	borderline	no	no	no	no	no	no	no
Ocular features	myopia, astigmatism, and nystagmus (improved with age)	nystagmus (improved with age)	alternating exotropia, borderline opsoclonus	none	oculomotor apraxia, ptosis	upbeat nystagmus (starting 6 weeks after birth)	strabismus, nystagmus (improved with age)	none	strabismus	myopia	myopia, astigmatism	none	reduced visual acuity
Epilepsy	no	yes	no	yes	no	yes	yes	no	no	yes	no	yes	yes
EEG findings	slow background suggestive of mild encephalopathy	bilateral synchronized high-amplitude spikes, epileptic potentials	normal	slow background, infantile spasms, multifocal spikes during sleep	not performed	intermittent hypsarrythmic pattern, infantile spasms	infantile spasms and then normal interictal EEG	left fronto-temporal spike waves focus, which diffuses in the right frontal region, activated by sleep	not performed	generalized slowing and generalized epileptiform discharges associated with myoclonic jerks	not performed	right temporal focus of high and polymorphic alfa spike-wave complexes, with ipsilateral propagation	left and right posterior and right frontal intermittent slowing, bilateral polyspikes during sleep, and excessive beta-activity (with medications)
Brain MRI findings	normal	delayed myelination, a small arachnoid cyst	mild cortical atrophy, thinning of corpus callosum	normal	normal	normal	cortical and white-matter atrophy, including vermian atrophy	increased signal intensity in FLAIR of the subcortical white matter of the frontal region	not performed	minimally increased T2 signal intensity on the occipital lobes	normal	increased signal intensity in FLAIR of the cortical matter of the parietal	normal

CADD, combined annotation-dependent depletion; EEG, electroencephalography; MRI, magnetic resonance imaging.