Comparison of patients with isolated SETD1B variants and SETD1B microdeletion
| De novo SETD1B variants | SETD1B microdeletions | All patients | |
| De novo inheritance | 8/8 | 3/4* | 11/12 |
| Sex (male) | 5/8 | 3/7 | 8/15 |
| Development | |||
| Speech impairment | 6/7 | 4/4 | 10/11 |
| Global developmental delay | 8/8 | 5/5 | 13/13 |
| Intellectual disability | 8/8 | 2/2 | 9/10 |
| Neurology | |||
| Seizures | 8/8 | 3/3 | 11/11 |
| Average age of onset (years) | 4.1† | 4.2‡ | 4.1 |
| Multiple seizure types | 6/8 | 3/3 | 9/11 |
| EEG abnormalities | 7/7 | 3/3 | 10/10 |
| Findings on brain imaging | 2/7 | 2/2 | 4/9 |
| Autism | 6/8 | 2/2 | 9/10 |
In total, there are 12 previously reported patients with either variants in SETD1B or microdeletions encompassing SETD1B.
Given that not all clinical reports commented on the presence of the same features (eg, not all reports comment on the presence of speech impairments), these values reflect the presence of reported features where available.
*Of previously reported patients with SETD1B microdeletions, only four families underwent parental genetic testing. In one, the microdeletion was inherited from an unaffected father.8
†One patient with onset reported by parents at age 12 years, and seven of eight patients with onset prior to 4 years.
‡Seizures only reported in three patients.