Table 1. Clinical data of patients and functional consequences of C × 47 mutations.
| Patient/sex | Age at disease onset, month | Age at last examination | Score of best motor functiona (age at walking, year) | Speech (age>1 year) | Education (age>5 year) | Course | Age at onset of motor degradation, year | Age at onset of speech deterioration, year | Mutation at nucleotide level | Mutation at protein level | Mutant alleles | Localization of C × 47 | Functional defect of C × 47 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| mt3548/M | 9 | 7 | 1 | + (D) | Special school | S | — | — | c.1193C>T | p.T398I | Het | PM | Dysfunction |
| G218/M | 12 | 6 | 4 (2) | + (D) | Regular school | SD | 5 | — | c.1193C>T | p.T398I | Het | PM | Dysfunction |
| G344/M | 3 | 1 | 2 | SI | — | — | c.445G>A | p.G149S | Het | ER, PM | Loss of function | ||
| mt3550/M | 9 | 5 | 2 | + | Special school | S | — | — | c.292_293 insGTA | p.A98G_V99 insT | Het | ER | Loss of function |
| G330/F | 1 | 17 | 4 (3.5) | + (D) | Regular school | SD | 8 (wcb 10) | 11 | c.793A>G | p.T265A | Hom | ER | Loss of function |
| G193/M | 12 | 14 | 2 | + (D; BD) | Special school | SD | 4 | 12 | c.706G>C | p.G236R | Hom | ND | Loss of function |
Mutations and clinical data previously described and published by our group.7 Mutation nomenclature is based on GJA12/GJC2 cDNA sequence (RefSeq NM_020435.2), +1 corresponds to the A of the first ATG.
a
Disease forms according to a development score (best motor function acquired): 0=no motor achievement; 1=head control; 2=sitting without aid; 3=walking with aid; 4=walking independently.
BD, buccofacial dyspraxia; D, dysarthria; ER, endoplasmatic reticulum; F, female; M, male; Het, heterozygous; Hom, homozygous; ND, not detectable; PM, plasma membrane; S, stable; SD, slow degradation; SI, slow improvement; wcb, wheelchair bound.