ADNP missense variant p.C687R disrupts chromatin regulation and GABAergic differentiation in Helsmoortel-Van der Aa syndrome.
Qi Chen, Xixi Liu, Mengnan Wu and 12 others
PMID 41943166WHAT IT FOUND
A single child's ADNP missense variant made the protein bind different places on the genome, and in her own reprogrammed cells it switched on genes that push developing neurons toward a GABAergic fate.
No treatment was tested.
Key findings
01Among people with a confirmed diagnosis, most ADNP variants were nonsense or frameshift changes, while in undiagnosed cases missense changes were the most common type and most were classified as variants of uncertain significance.
02The missense variant p.C687R changed the protein's behaviour in cells: instead of forming the small nuclear puncta seen with the normal protein, it spread diffusely through the nucleus, and in mouse embryos neurons carrying it stayed in the deep cortical layers instead of migrating into the cortical plate.
03In cells derived from the patient, the variant changed bivalent chromatin marks at hundreds of genes that were not yet being expressed differently, and a large share of those genes became active once the cells were pushed toward a GABAergic fate, including GABAergic genes such as NKX2-1 and GAD2.
STILL TO COME
How it was doneWhat they found
Read the rest of this summary
You get three full summaries a month, free, and we do not ask for a card. Search, the TL;DRs and your library stay unlimited either way.
What it does not show
All of the patient-derived work comes from one girl, using a single iPSC clone and compared with a single healthy control. The control was broadly matched for age but not for sex, and the authors say the one-to-one comparison should be read with caution. In a real patient one mutant copy of ADNP sits alongside a normal copy, and the study did not compare loss-of-function and gain-of-function effects in the same cells, so the mutant may be doing both at once. Much of the evidence comes from overexpressing the mutant protein in a kidney cell line that is not a neuron, at levels far above what a child would have. No mouse carrying the variant itself was made; the experiments delivered human ADNP genes into normal mouse embryos, so the physiological and behavioural consequences are unknown. Only one missense variant was studied in detail, and whether other ADNP missense variants behave the same way is not known. No treatment or clinical outcome was measured at any point.
Declared interests
The work was funded by the Natural Science Foundation of Anhui Province, the academic leaders development program of Children's Hospital of Fudan University, STI2030-Major Projects, the National Natural Science Foundation of China, and the Fundamental and Interdisciplinary Disciplines Breakthrough Plan of the Ministry of Education of China. The supplied text contains no competing-interest declaration and does not name any company that sells a treatment.
The easy way to misread this
Do not read this as proof that over-active GABAergic gene programmes cause ADNP syndrome, and do not read it as a treatment target. Almost all of the evidence comes from overexpressing the mutant protein in a kidney cell line and from mouse embryos, the patient-derived data come from one girl and one control, and the authors themselves say a gain-of-function reading is uncertain in a real patient who still carries one normal copy of the gene.
Summarised by AI from the full paper, without a clinician reviewing it. Check it against the source before it changes what you do. Read it on PubMed →