Table 1.
Summary of the clinical and genetic information of the analyzed cohort
| Individual 1 (family 1) | Individual 2 (family 1) | Individual 3 (family 2) | Individual 4 (family 3) | Individual 5 (family 4) | Individual 6 (family 5) | Individual 7 (family 6) | Individual 8 (family 7) | Individual 9 (family 8) | Individual 10 (Yoon et al., 201721) | |
|---|---|---|---|---|---|---|---|---|---|---|
| Variant GenBank: NM_018245 | c.2554C>G (p.Pro852Ala) | c.2554C>G (p.Pro852Ala) | c.2018G>A (p.Arg673Gln); c.1464T>C (p.Val488Val) | c.2201T>C (p.Phe734Ser); c.980C>T (p.Ala327Val) | c.660G>C (p.Trp220Cys); c.1472A>T (p.Asp491Val) | c.730C>T (p.Arg244Trp) | c.1658delG (p.Cys553Leufs∗16) | c.895A>G (p.Arg299Gly) | c.1318C>T (p.Arg440Ter) | c.2333C>T (p.Ser778Leu) |
| Inheritance | hom. | hom. | com. het. | com. het. | com. het. | hom. | hom. | hom. | hom. | hom. |
| AoO | birth | 1 year | 8 years | 6 years | 6 months | 5 months | 3 months | 3–4 months | 2 months | 1 year |
| DD/ID | mild DD | mild DD | mild DD | no | global DD | global DD and ID | mild ID | moderate to severe ID | global DD and ID | severe DD and ID |
| Seizures (onset) | 1X TC | no | no | abs., MA, TC, SE (N/A) | IS, TC (6 months) | focal-motor, TC (2 years) | no | no | yes (12 months) | no |
| Neurologic examination | mild GA | mild GA | GA, axonal neuropathy, spasticity | normal | hyp., no walking | spastic, quadriplegic, no walking | normal | hyp., walk with help | hyp., GA, walk with help | hyp., hypertonicity, spasticity, GA |
| EEG features | N/A | N/A | normal | N/A | hypsarrhytmia, multifocal/gen. spikes | diffuse spikes, slowed background activity | N/A | mild slowed background | T-R spikes | N/A |
| Hearing involvement | profound bi. | profound bi. | profound | no | no | no | no | no | bi. hearing deficit | no |
| Ophthalmological involvement | VI | no | retinopathy | no | VI, nystagmus | bi. optic atrophy | no | mild nystagmus | poor vision | no |
| Dys. features | no | no | hypomimia, scoliosis, pes cavus | no | bi. hip dysplasia, clonus with extension of right foot | high arched palate, scoliosis, microcephaly | scaphocephaly | no | bi. ptosis, highly arched palate, down slanting of eyes | some synophrys, large mouth, microcephaly |
| MRI | N/A | N/A | bi. unspecific T2 lesions | normal | global atrophy, diffuse T2 hyperintens., focus frontal | periv. leukomalacia, corpus callosum hypoplasia | R-F glioma | normal | normal | hypo plastic corpus callosum, global atrophy |
| Main phenotype | hearing deficit | hearing deficit | dysmorphic features | DEE | DEE | DEE | ID | ID | hearing and vision deficit, DEE | dysmorphic features, ID |
abs., absence; AoO, age of onset; bi., bilateral; com. het., compound heterozygous; DD, developmental delay; GA, gait ataxia; hom., homozygous, hyp., hypotonia; hyperintense., hyperintensity; ID, intellectual disability; IS, infantile spasms; MA, myoclonic-atonic; DEE, developmental and epileptic encephalopathy; N/A not available; periv., periventricular; R-F, right frontal; SE, status epilepticus; TC, tonic-clonic; VI, visual impairment.