A molecular-genetics report dated June 2021 confirmed a heterozygous, de novo nonsense variant in ASH1L: NM_018489.3:c.3838C>T, p.(Arg1280*). The variant was present in her blood and was not found in either parent's blood.
The laboratory classified the variant as pathogenic, citing PVS1 (very strong), PS2 (moderate), and PM2 (supporting), although the report also used the term "likely pathogenic" elsewhere. It described the ASH1L-associated intellectual-disability diagnosis as molecularly confirmed. At the time, the variant was absent from the population database cited by the laboratory and had no entry in the disease databases it listed.
The change introduces a premature stop at amino acid 1280. It occurs well before several important C-terminal regions of the ASH1L protein and is predicted to cause loss of normal full-length protein function. This predicted effect has not been tested directly with RNA or protein studies.
Because neither parent carried the variant in blood, the laboratory estimated the recurrence chance for another pregnancy at less than 1%, while noting that parental germline mosaicism cannot be excluded completely by blood testing.
The 2021 report listed an IQ of 45, ventricular extrasystoles with repeated ablations, rigidity or myotonia-like episodes, and myalgias. It explicitly said that the relationship of the cardiac and muscular findings to ASH1L remained unclear. This distinction is important: the ASH1L diagnosis provides a strong molecular explanation for her lifelong neurodevelopmental condition, but it does not prove that every cardiac, auditory, muscular, immune, skin, sleep, hormonal, orthopedic, or adult cognitive feature has the same cause.
In March 2026, re-evaluation of the exome data originally generated in 2021 did not identify another clinically relevant genetic finding beyond the known ASH1L variant. The indication included repeated ablations, tachycardia, rigidity or myotonia-like episodes, myalgias, and newer dementia-like symptoms. The laboratory concluded that the known ASH1L finding did not explain the tachycardia or dementia-like development at that time. Their causes remained unresolved.
A July 2026 clinical-genetics assessment offered this interpretation:
- It records intellectual disability and autism-spectrum disorder and relates both to the pathogenic ASH1L variant. The letter does not specify how the autism diagnosis was established.
- It records memory difficulty for approximately two years, especially involving short-term memory, together with worsening cognitive performance.
- It confirms that no second clinically relevant exome finding was identified to explain the rhythm disorder, tic disorder, or cognitive worsening.
- It considers a relationship between the memory difficulty and ASH1L conceivable, but does not consider the presentation consistent with a primary neurodegenerative disease causing progressive loss of cognitive skills and visible cortical changes.
- It states that current evidence does not demonstrate increased dementia risk in people with pathogenic ASH1L variants, while emphasizing that the available evidence is limited.
- It notes that tic disorders can occur with ASH1L-associated intellectual disability, particularly with accompanying autism-spectrum features, and recommends continued neurologic involvement. A possible research connection with a neurodegenerative-disease center was also suggested.
- It notes research implicating ASH1L in aging processes within individual cells, but explicitly states that there is no evidence of generalized premature aging in people with ASH1L variants.
- It raises the possibility that the early cervical-spine degeneration might relate to the ASH1L variant and cellular-aging biology. The connection remains unproven.
- It states that the cause of the cardiac rhythm disorder remains unclear and gives the geneticist's opinion that it is probably not genetic.
- It recommends measurement of estrogen, LH, FSH, and testosterone, including assessment for possible primary ovarian insufficiency.
In July 2026, she and her parents enrolled in an international rare-disease genetics research project. No clinical findings from that research have been reported.