Table 2.
KAT6B Sequence Variants in 19 Individuals Tested
| Individual | Mutation | Exon | Parents | Comments |
|---|---|---|---|---|
| 1 | NM_012330.2(KAT6B):c.4405dup (p.Ser1469Phefs∗18) | 18 | not tested | typical; case 322 |
| 2 | NM_012330.2(KAT6B):c.5370_5373dup (p.Ile1792GlnfsX12) | 18 | not tested | typical |
| 3 | NM_012330.2(KAT6B):c.3018del (p.Glu1007Argfs∗5) | 15 | negative | typical; also has 1q21.1 microdup |
| 4 | NM_012330.2(KAT6B):c.4069G>T (p.Glu1357∗) | 18 | negative | typical. Figure 3 in Day et al.6 |
| 5 | NM_012330.2(KAT6B):c.4205_4206del (p.Ser1402Cysfs∗5) | 18 | negative | typical |
| 6 | NM_012330.2(KAT6B):c.5734A>T (p.Arg1912∗) | 18 | not tested | typical case 222 |
| 7 | NM_012330.2(KAT6B):c.5030del (p.Thr1677Metfs∗38) | 18 | not tested | typical |
| 8 | NM_012330.2(KAT6B):c.5201_5210dup (p.Gln1737Hisfs∗41) | 18 | not tested | typical |
| 9 | NM_012330.2(KAT6B):c.5201_5210dup (p.Gln1737Hisfs∗41) | 18 | negative | typical |
| 10 | NM_012330.2(KAT6B):c.4205_4206del (p.Ser1402Cysfs∗5) | 18 | not tested | typical case 422 |
| 11 | NM_012330.2(KAT6B):c.527dup (p.Tyr176∗) | 3 | not tested | SBBYSS-like, not typical |
| 12 | NM_012330.2(KAT6B):c.4911_4921del (p.Val1638Alafs∗27) | 18 | negative | typical |
| 13 | NM_012330.2(KAT6B):c.5389C>T (p.Arg1797∗) | 18 | negative | typical |
| 14 | NM_012330.2(KAT6B):c.1078G>A (p.Glu360Lys) | 8 | not tested | milder phenotype |
| 15 | negative | atypical | ||
| 16 | negative | atypical | ||
| 17 | negative | atypical; has 1p36 microdeletion | ||
| 18 | negative | atypical | ||
| 19 | negative | atypical |
This table shows the Sanger sequencing results from the cohort of individuals tested. Individuals 1–4 are those where exome sequencing was carried out. Twelve of the individuals were judged to have a typical clinical presentation, and sequence variants predicted to cause protein truncation were identified in all of these. Eleven of these twelve variants were in exon 18. In addition, a truncating mutation was identified in exon 3 in a less typical individual and a missense variant was identified in exon 8 in an individual with a much milder phenotype. This boy had only a moderate learning disability and significantly less speech delay. This missense variant has subsequently been identified in a normal control and is now considered to be unrelated to the clinical presentation. The chance of finding a KAT6B mutation in our series of clinically typical individuals was therefore high.