Table 1
Main clinical features of the affected individuals with biallelic variants in MED27
| Category/clinical feature | n (percentage) |
|---|---|
| Sex | 28 males, 29 females |
| Consanguinity | 21/30 (70%) |
| Mean age at the most recent follow-up, years | 17 ± 12.4 (range 0.1–45) |
| Abnormal prenatal and perinatal history | 6/55 (11%), NA 2 |
| Mortality | 9/57 (16%) |
| Failure-to-thrive | 11/47 (24%), NA 10 |
| Microcephaly | 24/39 (62%), NA 18 |
| Cognitive impairment/ID | 54/55 (98%), NA 2 |
| Severity of ID | 38% mild; 30% moderate-to-severe; 21% severe-to-profound; 10% NA |
| Hypotonia in infancy | 32/43 (74%), NA 14 |
| Motor delay | 48/53 (91%), NA 4 |
| No acquisition of independent gait | 23/52 (44%), NA 5 |
| Speech delay/non-verbal | 53/53 (100%), NA 4 |
| Able to perform ADLs | 17/49 (35%), NA 8 |
| Regression | 19/52 (37%), NA 5 |
| Progressive course | 20/47 (43%), NA 10 |
| Dysmorphic features | 20/52 (38%), NA 5 |
| Bilateral cataracts | 49/55 (89%), NA 2 |
| Seizures | 27/54 (50%), NA 3 |
| Mean age of seizure onset, years | 6.2 ± 2.3 (range 0.1–10) |
| Dysarthria | 19/29 (66%), NA 28 |
| Hypotonia at follow-up | 28/51 (55%), NA 9 |
| Spasticity | 26/51 (51%), NA 6 |
| Cerebellar ataxia | 20/62 (63%), NA2 5 |
| Dystonia/dyskinesia | 30/49 (61%), NA 8 |
| Joint contractures | 20/52 (38%), NA 5 |
| Cerebellar atrophy | 36/36 (100%); NA 21; mild 22/36 (61%); moderate-to-severe 14/36 (39%) |
| Pontine hypoplasia | 17/36 (47%) |
| Basal ganglia abnormalities | 32/36 (89%) |
ADL = activities of daily living; ID = intellectual disability; NA = not available or not applicable/unable to assess.