Assessment & Research

Shorter Telomeres and Faster Telomere Attrition in Individuals With Five Syndromic Forms of Intellectual Disability: A Systematic Review and Meta-Analysis.

Hanley et al. (2025) · Journal of intellectual disability research : JIDR 2025
★ The Verdict

People with syndromic ID have shorter, faster-fading telomeres, signaling earlier biological aging.

✓ Read this if BCBAs working with teens or adults who have Down, Fragile X, Rett, Angelman or similar syndromic ID.
✗ Skip if Clinicians serving only ASD or non-syndromic ID — the data do not speak to those groups.

01Research in Context

01

What this study did

The team pooled every paper that measured telomeres in people with five genetic syndromes that cause intellectual disability.

They compared the length and yearly loss of these protective chromosome caps with data from people without ID.

Down syndrome was the biggest group, but Fragile X, Rett, Angelman and two others were also counted.

02

What they found

Across all studies, people with these syndromes had clearly shorter telomeres and lost them faster.

Shorter telomeres are a red flag for faster biological aging, even when the person is still young.

03

How this fits with other research

Lin et al. (2015) already showed that early aging signs like frail eyes and poor memory predict weaker daily-living skills in teens and adults with Down syndrome. Whaling et al. (2025) now gives the cell-level proof that this aging starts sooner.

Gastelum Guerrero et al. (2024) found worse lipid profiles in Down syndrome, another early-aging marker. The new review adds telomere loss to the same picture: the body ages faster on several fronts.

Ye et al. (2024) saw no simple telomere difference in adults with ASD. That looks like a clash, but their group had ID plus ASD, not syndromic ID alone. Different diagnoses, different biology — no real contradiction.

04

Why it matters

Your learners with Down syndrome or other syndromic ID are on a faster biological clock. Plan early for skills that must last: strengthen fitness, teach self-care routines and schedule health screens sooner. Track adaptive scores yearly so you spot decline before it blocks learning.

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02At a glance

Intervention
not applicable
Design
systematic review
Sample size
847
Population
intellectual disability, down syndrome
Finding
not reported

03Original abstract

BACKGROUND: People with intellectual disability suffer complex challenges due to adaptive functioning limitations, high rates of chronic diseases and shortened lifespans compared with the general population. Telomere shortening is a hallmark of ageing, and short telomeres are linked to neurological disorders. The main objective of this systematic review and meta-analysis was to identify any differences in telomere length and the rate of telomere attrition in leukocytes and fibroblasts from people with intellectual disability and controls. METHODS: PubMed, Scopus and ScienceDirect were searched. Articles that compared telomere length in individuals with intellectual disability to apparently healthy age-matched controls were included. Risk of bias was assessed using the AXIS tool and data were analysed using CMA. RESULTS: Fifteen studies comprised of 17 comparisons provided data and were included in meta-analyses. Compared with healthy controls (N = 481), people with intellectual disability (N = 366) from a known genetic syndrome (Cri du chat, Down, Hoyeraal-Hreidarsson, Williams or Nicolaides-Baraitser) possessed shorter leukocyte telomeres (SMD: -0.853 [95% CI: -1.622 to -0.084], p = 0.03). Similarly, relative to controls (N = 16), people with syndromic intellectual disability (N = 21) possessed shorter fibroblast telomeres (-1.389 [-2.179 to -0.599], p = 0.001). Furthermore, people with syndromic forms of intellectual disability also demonstrated a faster rate (2.09-fold) of telomere shortening. CONCLUSIONS: Consistent with epidemiological findings on mortality and morbidity risk, people with syndromic intellectual disability appear to undergo a faster rate of biological ageing compared to the general population. These findings emphasise the need for healthy ageing lifestyle (i.e., exercise and stress management) and therapeutic interventions for people with syndromic intellectual disability.

Journal of intellectual disability research : JIDR, 2025 · doi:10.1111/jir.13244