Abstract

Introduction:

Carriers of the FMR1 gene premutation (PM) are at increased risk for Fragile X-associated PM Conditions (FXPAC). Some clinically significant symptoms can be further classified as Fragile X-associated Neuropsychiatric Disorders (FXAND). Many FXAND-related cases may go underrated and untreated. This study aimed to investigate the rates of FXAND-related symptoms among female PM carriers.

Methods:

The study was conducted at the Belgrade Fragile X Clinic on a clinical sample of 35 women with the PM and 35 controls using an adapted version of the Symptom Impact Questionnaire and the Fatigue Assessment Scale. The survey was designed to collect data on FXAND symptoms, including chronic pain, fatigue, anxiety, and depressive symptoms. Each symptom was self-rated by participants on a scale from 0 to 10. Data were analyzed using appropriate statistical methods.

Results:

Women with the PM (mean age: 44.51 ± 12.90 y.; 90.51 ± 22.04 CGG repeats) had statistically significant higher frequency and severity of chronic pain (p = 0.03; p = 0.02) and fatigue (p = 0.001 for both) in contrast to age-matched controls. Although the prevalence of anxiety symptoms was not significantly different between groups, the severity of anxiety symptoms were significantly higher in the PM group (p < 0.001), and was positively correlated with chronic fatigue (p = 0.003 vs. p = 0.27 in controls). Depressive symptom frequency and severity did not differ between groups (p = 0.47; p = 0.55), but there were a significant positive correlation between anxiety and depressive symptoms in the PM group (p = 0.003). Depressive symptoms were also positively correlated with chronic fatigue in the PM group (p = 0.02), but not in controls (p = 0.58). Compared to controls, PM carriers reported more frequently lower energy, poorer sleep, greater memory issues, cognitive difficulties, balance problems, and increased sensory sensitivity (p ≤ 0.001, all).

Conclusion:

Female PM carriers experience significantly higher frequency and severity of FXAND-related symptoms. Our findings of an association between fatigue, anxiety, and depressive symptoms highlight the need for comprehensive screening and underscore the importance of recognizing and treating individuals with FXAND.

1 Introduction

The FMR1 (Fragile X Messenger Ribonucleoprotein 1) gene, located on the X chromosome at position Xq27.3, encodes the FMR1 protein (FMRP), an RNA-binding protein essential for proper synaptic development and plasticity (Richter and Zhao, 2021). The FMR1 gene contains between 5 and 44 CGG trinucleotide repeats in its 5′ untranslated region (UTR), with 29 and 30 repeats being the most common (Richter and Zhao, 2021). However, when CGG repeats undergo abnormal expansion, different classes of expanded alleles are recognized: (i) intermediate or gray zone (45–54 CGG repeats) with unclear clinical significance, (ii) premutation (PM) with 55–200 CGG repeats, and (iii) full mutation (FM) with ≥ 200 CGG repeats (Maddalena et al., 2001; Wheeler et al., 2014). The methylation of the FM and other epigenetic modifications leads to the silencing of the FMR1 gene, resulting in the loss of FMRP production. Clinically, this condition is recognized as fragile X syndrome (FXS) (Maddalena et al., 2001; Wheeler et al., 2014). The absence of FMRP impairs synaptic plasticity, leading to abnormalities such as delayed dendritic spine maturation and altered synapse structure—hallmarks of FXS (Crawford et al., 2020). FXS is a rare genetic disorder, occurring in approximately 1 in 4,000 males and 1 in 8,000 females, and it is the most common cause of inherited intellectual disability (ID) and autism spectrum disorder (ASD) (Hunter et al., 2014). In contrast, the PM of the FMR1 gene is relatively common in the general population, and its prevalence varies across studies (Seltzer et al., 2012a; Tassone et al., 2013; Hunter et al., 2014; Hnoonual et al., 2024). Combining data from previously published studies, the estimated prevalence of the PM in the general population ranges from 1 in 250 to 1 in 850 males and 1 in 110 to 1 in 300 females (Seltzer et al., 2012a; Tassone et al., 2013; Hunter et al., 2014; Hagerman et al., 2017; Hnoonual et al., 2024).

While PM carriers do not develop FXS, some of them experience symptoms or conditions related to the PM (Tassanakijpanich et al., 2021; Tassone et al., 2023). The condition’s complexity, ranging from no symptoms to neuropsychiatric or physical issues, makes it challenging to find terminology that accurately reflects everyone’s experience without causing confusion or exclusion. Terms like “mutation” or “disorder” can carry negative connotations or imply illness, which many in the community find stigmatizing or misleading, especially for those who do not experience significant symptoms (Tassone et al., 2023). On the other hand, a carrier can suggest that a person is unaffected by the PM, even when they may experience symptoms (Tassone et al., 2023). Clinicians and researchers prioritize scientific precision, while individuals and families seek terms that are accessible and non-discriminatory. Terminology also evolves, which can lead to inconsistency. Nowadays, the most used term for such a group of conditions is the “Fragile X PM-associated conditions” (FXPAC) as an umbrella term that encompasses the range of involvement from the PM (Johnson et al., 2020; Tassone et al., 2023).

FXPAC encompasses several clinical entities: FXTAS (Fragile X-associated Tremor/Ataxia Syndrome)—a neurodegenerative disorder characterized by tremors and ataxia in older men and some women; FXPOI (Fragile X-associated Primary Ovarian Insufficiency)—premature ovarian insufficiency in women; and FXAND (Fragile X-associated Neuropsychiatric Disorders)—a group of neuropsychiatric disorders that can occur in the PM carriers of all ages (Tassone et al., 2023). The pathophysiological mechanisms underlying FXPAC involve the toxic effects of elevated levels of FMR1 mRNA, which positively correlate with the CGG repeats in the PM range, as well as mitochondrial dysfunction (Tassone et al., 2007; Giulivi et al., 2016).

FXAND represents a relatively under-recognized clinical category within the FXPAC spectrum, encompassing a wide range of symptoms, including anxiety, depression, attention disorders (e.g., ADHD), autistic traits, obsessive-compulsive symptoms, sleep disturbances, chronic pain, chronic fatigue, etc. (Hagerman et al., 2018; Aishworiya et al., 2022). These manifestations may be present in children, adolescents, and adults carrying the PM, regardless of gender (Hagerman et al., 2018; Aishworiya et al., 2022). In clinical practice, FXAND symptoms are often underdiagnosed or misattributed to other neuropsychiatric conditions, highlighting the need for a better understanding and their timely identification (Tassone et al., 2023).

Although awareness of FXAND has increased in recent years, systematic data on chronic pain, fatigue, and emotional distress in female PM carriers remain limited and under-integrated into clinical practice. By focusing on these frequently overlooked yet clinically impactful symptom domains, the present study aims to expand the current understanding of the FXAND phenotype in female PM carriers. Improved characterization of these features has the potential to inform earlier identification, refine screening strategies, and support more comprehensive counseling and clinical management approaches tailored to women with the PM. Specifically, this study aimed to investigate the presence, severity, and interrelationship of FXAND-related symptoms such as chronic pain, fatigue, anxiety, and depressive symptoms among female PM carriers.

2 Materials and methods2.1 Participants

The prospective study enrolled adult females who were divided into two groups: (i) the PM group, which included 35 unrelated female PM carriers (CGG repeat size 55–200), and (ii) the control group, which included 35 age-matched females who had a number of CGG repeats in the FMR1 gene within the normal range. The number of CGG repeats in the FMR1 gene in all participants was determined via PCR approaches using AmplideX® PCR/CE FMR1 Kit (Asuragen, Austin, TX, United States) (Chen et al., 2010; Filipovic-Sadic et al., 2010). Females, both PM carriers and controls, were enrolled after genetic testing, which was conducted as part of cascade screening following genetic counseling for a child or sibling diagnosed with FXS. Specifically, control females were members of families with fragile X, but they tested negative for the FMR1 mutation and did not have children with ID and/or ASD. Exclusion criteria included FXTAS.

Ethical approval for the study was obtained from the IRB at the Special Hospital for Cerebral Palsy and Developmental Neurology (SHCPDN) in Belgrade, Serbia, where the Fragile X Clinic is established (No. 221; 691).

2.2 Data collection

During this observational study, data were collected through structured, in-person interviews by a clinician-researcher with expertise in the field of fragile X, with participant responses recorded anonymously. The interviewer was aware of the participant group’s status during the assessment. The structured, in-person interviews were based on a questionnaire that was developed using two instruments: the Symptom Impact Questionnaire (SIQR), the version of the Revised Fibromyalgia Impact Questionnaire (FIQR), and the Fatigue Assessment Scale (FAS) (Michielsen et al., 2003; Bennett et al., 2009). These instruments were selected for their strong psychometric properties, quick completion time (under 2 min), and ease of scoring. For this study, SIQR was used with permission of Mapi Research Trust (license No. 120280).1 In addition, the use of the FAS was permitted by the “ild care foundation”.2 Finally, the SIQR and FAS were combined into a single questionnaire, supplemented with basic socio-demographic items and self-assessment of the symptoms’ presence (symptoms of chronic pain, chronic fatigue, anxiety, and depression), and administered to all study participants. The final form of the questionnaire was conducted in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines (Cuschieri, 2019).

Specifically, the data on chronic pain and related symptoms were collected by SIQR, which is commonly used in non-fibromyalgia patients and which does not use the word “fibromyalgia” (Bennett et al., 2009). The 2-page SIQR in English is freely available through the scientific article published in 2009 by Bennett et al. (2009). The SIQR comprises three domains. The domain 1 (function) measures the level of difficulty participants have experienced in performing activities over the past 7 days. Nine items were included in the domain 1, evaluating participants’ ability to brush or comb their hair (which is associated with shoulder girdle pain), walk continuously for 20 min, prepare a homemade meal, vacuum/scrub/sweep floors, lift and carry groceries, climb one flight of stairs, change bed sheets, sit in a chair for 45 min, and go grocery shopping. Domain 2 (overall impact): includes two items that assess the overall impact of any medical problems over the past 7 days—specifically, the perceived impact of medical problems on weekly goal accomplishment and the sense of being overwhelmed by medical problems and pain. Domain 3 (symptoms): 10 items were used to measure the severity of common pain-related symptoms, including pain, fatigue, stiffness, sleep quality, depression, memory issues, anxiety, tenderness, balance problems, and sensory sensitivities. Responses were recorded on a 0–10 numeric rating scale, in line with the original SIQR format, where 0 indicates no difficulty or symptom severity and 10 represents the worst possible difficulty or severity. Individual domain scores and a total SIQR score were calculated for each participant (Bennett et al., 2009).

Alongside the SIQR, the items from the FAS were incorporated to evaluate the presence and type of fatigue specifically (Michielsen et al., 2003). The FAS consists of 10 statements measuring both physical and mental fatigue. Participants rated their agreement with statements such as “I am bothered by fatigue,” “Physically, I feel exhausted,” “I have problems thinking clearly,” and “Mentally, I feel exhausted,” using a five-point Likert scale ranging from 1 (“never”) to 5 (“always”). Two positively phrased items: “I have enough energy for everyday life” and “When I am doing something, I can concentrate quite well”, were reverse scored to ensure consistent directionality, so that higher scores uniformly indicate greater fatigue. Sub-scores for total fatigue, mental fatigue, and physical fatigue were calculated according to the standard FAS scoring guidelines (Michielsen et al., 2003).

2.3 Statistical analyses

Descriptive statistics, including medians and ranges (min–max), were calculated for individual items, domain scores, and total scores. Chi-square tests were applied for frequency comparisons, while the independent t-test and Mann–Whitney U test were used for comparing continuous variables, depending on the normality of distribution. Specifically, multiple symptom domains were analyzed using separate Mann–Whitney U tests. No formal correction for multiple comparisons was applied to avoid an increased risk of Type II error given the small sample size and the correlated nature of the outcomes (VanderWeele and Mathur, 2018). Therefore, the possibility of Type I error should be considered when interpreting the results. Spearman’s rank correlation was used to assess relationships between variables. All analyses were performed using IBM SPSS Statistics, with a significance level at p < 0.05.

3 Results3.1 Participants

This prospective study included 35 female participants aged from 23 to 75 years (mean age: 44.51 ± 12.90 y.; median 42 y.) who are carriers of the PM in the FMR1 gene (PM group) and 35 age-matched females in the same age range who are non-carriers (mean age: 44.54 ± 12.91 y.; median 42 y.) as a control group. Among the women in the PM group, 22 (62.86%) had a child diagnosed with FXS. As expected, the number of CGG repeats in the FMR1 gene was statistically significantly higher (p < 0.001) in the PM group (90.51 ± 22.04; median 85; range: 59–160) than in the control group (29.26 ± 3.15; median 30; range 21–35). There was also a statistically significant difference in body mass index (BMI) between groups, and PM carriers had a higher mean BMI compared to the control group (27.49 ± 5.30 in PM group vs. 23.55 ± 3.55 in control group; p = 0.001).

Chronic pain and chronic fatigue were statistically significantly more frequently self-reported in the PM group compared with the control group (PM group: 51.4% vs. control group: 25.7%; p = 0.027 for chronic pain; and PM group: 51.4% vs. control group: 11.4%; p = 0.001 for chronic fatigue). PM carriers more frequently reported anxiety symptoms than controls, but without statistical significance (PM group: 80.0% vs. control group: 62.9% p = 0.190). There was no statistically significant difference in the self-reported frequency of depressive symptoms between groups (PM group: 51.4% vs. control group: 62.9%; p = 0.469).

Demographic characteristics and self-reported symptom frequencies are presented in Table 1.

Participant characteristicsPM groupControl grouppN = 35N = 35Age (mean ± SD)44.51 ± 12.9044.54 ± 12.910.993CGG repeats (mean ± SD)90.51 ± 22.0429.26 ± 3.15<0.001CGG median (range)85 (59–160)30; (21–35)<0.001Having a child with FXS, N (%)22 (62.86)0 (0)/BMI (mean ± SD)27.49 ± 5.3023.55 ± 3.550.001Chronic pain, N (%)18 (51.4)9 (25.7)0.027Chronic fatigue, N (%)18 (51.4)4 (11.4)0.001Anxiety symptoms, N (%)28 (80.0)22 (62.9)0.185Depressive symptoms, N (%)18 (51.4)22 (62.9)0.469

Demographic characteristics and self-reported symptom frequencies of the study participants.

PM, premutation in the FMR1 gene, FXS, fragile X syndrome; N, number; BMI, body mass index. Bold: statistically significant p ≤ 0.05.

3.2 Manifestations of chronic pain and its impact on PM carriers’ functioning

In the present study, PM carriers reported statistically significantly higher pain levels than controls (median: 3, range: 0–10 in PM group vs. median: 1, range: 0–5 in control group; p = 0.021). Spearman correlation analysis revealed a moderate positive correlation between pain level and age in the PM group (ρ = 0.407, p = 0.002), while no such correlation was found in the control group (ρ = 0.040, p = 0.819). BMI was not significantly correlated with pain level in either the PM group (ρ = 0.188, p = 0.280) or the control group (ρ = 0.118, p = 0.500). In the PM group, pain level was not significantly correlated with CGG repeat number (ρ = −0.216, p = 0.213), nor was it significantly associated with having a child with FXS (p = 0.63). Pain levels did not significantly differ between PM carriers who have a child with FXS (median: 3, range: 0–10) and those without (median: 3.5, range: 0–10; p = 0.78).

In addition, there were no statistically significant differences between groups in terms of the reported impact of pain on weekly goal accomplishment or feelings of being overwhelmed by symptoms (median impact level: 0 in both groups; range: 0–10 in PM group and 0–3 in control group; p = 0.34 for both comparisons). A statistically significant difference in levels of pain-related limitations between groups was found for brushing or combing hair (PM group: median 0, range 0–10 vs. control: median 0, range 0–0; p = 0.006), whereas other activities did not show significant group differences. Detailed comparisons are presented in Table 2.

Symptom Impact Questionnaire (SIQR) itemsPM groupControl grouppN = 35N = 35median (min-max)median (min-max)Domain 11. Difficulty brushing or combing hair0 (0–10)0 (0–0)0.0062. Difficulty walking continuously for 20 min0 (0–10)0 (0–4)0.1063. Difficulty preparing a homemade meal0 (0–10)0 (0–2)0.5474. Difficulty vacuuming, scrubbing, sweeping floors0 (0–10)0 (0–4)0.245. Difficulty lifting and carrying a bag full of groceries1 (0–10)0 (0–3)0.0596. Difficulty climbing one flight of stairs0 (0–10)0 (0–4)0.0977. Difficulty changing bed sheets0 (0–10)0 (0–3)0.7518. Difficulty sitting in a chair for 45 min0 (0–10)0 (0–3)0.529. Difficulty going shopping for groceries0 (0–10)0 (0–5)0.979Domain 21. Being able to accomplish most set goals for week0 (0–10)0 (0–3)0.342. Overwhelmed by medical problems0 (0–10)0 (0–4)0.328Domain 31. Pain level/severity3 (0–10)1 (0–5)0.0212. Energy level5 (0–10)3 (0–5)<0.0013. Level of stiffness1 (0–7)0 (0–4)0.14. Quality of sleep5 (0–10)2 (0–5)0.0015. Level of depression1 (0–9)1 (0–6)0.5526. Level of memory problems3 (0–10)0 (0–3)<0.0017. Level of anxiety4 (0–9)1 (0–4)<0.0018. Level of tenderness to touch3 (0–9)0 (0–5)0.0929. Level of balance problems2 (0–8)0 (0–3)<0.00110. Level of sensitivity to loud noises, bright lights, odors, and cold3 (0–10)1 (0–5)0.001

Summary of symptom impact questionnaire (SIQR) results of the study participants.

PM, premutation in the FMR1 gene; N, number. Bold: statistically significant p-value ≤ 0.05.

3.3 Manifestations of chronic fatigue and its impacts on PM carriers’ functioning

The overall fatigue levels were statistically significantly higher in the PM group (median: 23, range: 11–49) compared to the control group (median: 17, range: 10–24; p = 0.001). Correlation analyses showed no significant relationship between fatigue level and age in the PM and control groups (PM group: ρ = 0.065, p = 0.713; control group ρ = −0.334, p = 0.060). BMI was not significantly correlated with fatigue in either group (PM group: ρ = 0.099, p = 0.571; control: ρ = −0.238, p = 0.168). In the PM group, fatigue level was not significantly correlated with CGG repeat number (ρ = −0.057, p = 0.713), nor was it associated with having a child with FXS (p = 0.83). Fatigue scores did not significantly differ between PM participants with (median: 26, range: 13–49) and without (median: 21.5, range: 11–36) a child with FXS (p = 0.41).

Specifically, the PM carriers reported being statistically significantly more affected by fatigue (p = 0.002), becoming tired more easily (p = 0.006), and feeling physically exhausted more frequently (p = 0.001) (PM group: median score 2, range 1–5 vs. control group: median score 2, range 1–3, for all parameters). The PM group also scored statistically significantly higher on both the mental fatigue (median: 9, range: 5–25 in PM group vs. 8, range: 5–12 in control group; p = 0.034) and physical fatigue subscales (median: 11, range: 6–24 in PM group vs. 9, range: 5–14 in control group; p < 0.001). Furthermore, PM carriers reported having sufficient energy for daily life less frequently than controls (p = 0.005). Detailed comparisons are presented in Table 3.

Fatigue Assessment Scale (FAS) itemsPM groupControl grouppN = 35N = 35median (min-max)median (min-max)1. Being bothered by fatigue2 (1–5)2 (1–3)0.0022. Getting tired very quickly2 (1–5)2 (1–3)0.0063. Doing little during the day2 (1–5)2 (1–3)0.7264. Having enough energy for everyday life2 (1–5)2 (1–3)0.0055. Feeling physically exhausted2 (1–5)2 (1–3)0.0016. Having problems starting things2 (1–5)2 (1–3)0.0817. Having problems thinking clearly2 (1–5)1 (1–2)0.0018. Feeling no desire to do anything2 (1–5)2 (1–3)0.3499. Feeling mentally exhausted2 (1–5)2 (1–3)0.05710. Being able to concentrate quite well when doing something2 (1–4)2 (1–2)0.068Score fatigue23 (11–49)17 (10–24)0.001Score mental fatigue9 (5–25)8 (5–12)0.034Score physical fatigue11 (6–24)9 (5–14)<0.001

Summary of fatigue assessment scale results of the study participants.

PM, premutation in the FMR1 gene; N, number. Bold: statistically significant p ≤ 0.05.

Finally, fatigue and pain levels were statistically significantly positively correlated in the control group (ρ = 0.557, p = 0.001), but not in the PM group (ρ = 0.321, p = 0.060).

3.4 Manifestations of anxiety symptoms and their impacts on PM carriers’ functioning

The severity of anxiety symptoms was statistically significantly higher in the PM group (median: 4, range: 0–9) compared to controls (median: 1, range: 0–4; p < 0.001) (Table 2). The severity of anxiety symptoms was not significantly correlated with age in the PM group (ρ = −0.257, p = 0.163). Interestingly a statistically significant moderate negative correlation was found in the control group (ρ = −0.631, p < 0.001). BMI was not significantly associated with anxiety symptoms in either group (PM group: ρ = −0.128, p = 0.462; control group: ρ = −0.213, p = 0.219). In the PM group, the severity of anxiety symptoms was not significantly correlated with CGG repeat number (ρ = 0.106, p = 0.543), nor was the presence of anxiety symptoms significantly associated with having a child with FXS (p = 0.38). The level of anxiety symptoms did not differ significantly between PM participants with a child with FXS (median: 4, range: 0–8) and those without (median: 4.5, range: 0–9; p = 0.72).

The presence of anxiety symptoms was not significantly associated with chronic pain in either the PM (p = 0.69) or control group (p = 0.78), and there was no significant correlation between the severity of anxiety symptoms and pain levels in either group (PM: ρ = 0.191, p = 0.273; control: ρ = 0.088, p = 0.613). In contrast, the presence of anxiety symptoms was statistically significantly associated with chronic fatigue in the PM group (p = 0.003) but not in the control group (p = 0.27). The severity of anxiety symptoms was positively correlated with fatigue levels in both groups (PM: ρ = 0.689, p < 0.001; control: ρ = 0.508, p = 0.002).

3.5 Manifestations of depressive symptoms and their impacts on PM carriers’ functioning

There was no statistically significant difference in the severity of depressive symptoms (median: 1, range: 0–9 vs. median: 1, range: 0–6; p = 0.55) (Table 2).

The severity of depressive symptoms was not significantly correlated with age in either group (PM: ρ = −0.162, p = 0.351; control: ρ = −0.188, p = 0.279). BMI was also not significantly associated with the severity of depressive symptoms (PM group: ρ = −0.044, p = 0.804; control group: ρ = 0.209, p = 0.869). In the PM group, the severity of depressive symptoms was not significantly correlated with CGG repeat number (ρ = −0.082, p = 0.639), nor was it significantly associated with having a child with FXS (p = 0.36). The severity of depressive symptoms did not differ significantly between PM carriers with a child with FXS (median: 2, range: 0–9) and those without (median: 0, range: 0–9; p = 0.45).

To assess symptoms commonly associated with depression, such as reduced motivation and cognitive difficulties, participants were asked about their motivation, ability to concentrate, and sense of accomplishment in daily life. Individuals with PM often reported feeling no desire to do anything, feeling mentally exhausted, feeling like they accomplish little in a day, and having more difficulty starting an activity more frequently than the control group, but none of these differences were statistically significant (PM group: median 2, range 1–5 vs. control group: median 2, range 1–3; all comparisons and p = 0.349; p = 0.057; p = 0.726; p = 0.081 respectively) (Table 3). Additionally, the PM group reported being able to concentrate well when engaged in an activity slightly less frequently than the control group, though this difference was also not statistically significant (median 2, range 1–4 vs. median 2, range 1–2; p = 0.068) (Table 3). There was a significant positive correlation between anxiety and depressive symptoms in both groups (PM: p = 0.003; control: p < 0.001), and the severity of depressive symptoms was statistically significantly positively correlated with anxiety levels in both PM (ρ = 0.697, p < 0.001) and control (ρ = 0.452, p = 0.006) groups.

The presence of depressive symptoms was not significantly associated with chronic pain in either group (PM: p = 0.74; control: p = 0.78). Depressive symptoms were statistically significantly associated with chronic fatigue in the PM group (p = 0.018), but not in the control group (p = 0.58). The severity of depressive symptoms was statistically significantly positively correlated with fatigue levels in both groups (PM: ρ = 0.505, p = 0.002; control: ρ = 0.697, p < 0.001).

3.6 Other FXAND-associated manifestations

As presented in Table 2, PM group also reported lower energy levels (PM group: median score 5, range 0–10 vs. control group: median score 3, range 0–5; p < 0.001), poorer sleep quality (PM group: median score 5, range 0–10 vs. control group: median score 2, range 0–5; p = 0.001), more pronounced balance issues (PM group: median score 2, range 0–8 vs. control group: median score 0, range 0–3; p < 0.001), and greater sensory sensitivity to loud sounds, smells, and cold (PM group: median score 3, range 0–10 vs. control group: median score 1, range 0–5; p = 0.001) (Table 2). On the other hand, there was no statistically significant difference between the two groups in terms of stiffness severity (PM group: median score 1, range 0–7 vs. control group: median score 0, range 0–4; p = 0.10), or tenderness to touch (PM group: median score 3, range 0–9 vs. control group: median score 0, range 0–5; p = 0.09) (Table 2).

Additionally, the PM group exhibited significantly greater memory difficulties (PM group: median score 3, range 0–10 vs. control group: median score 0, range 0–3; p < 0.001), significantly more frequent difficulty thinking clearly (PM group: median score 2, range 1–5 vs. control group: median score 1, range 1–2; p = 0.001) (Table 3) and significant balance problems compared to controls (PM group: median score 2, range 0–8 vs. control group: median score 0, range 0–3; p < 0.001) (Table 2).

4 Discussion

This study underscores the importance of monitoring FXAND-related symptoms in carriers of the FMR1 PM. Although there is ongoing scientific debate concerning the clinical relevance of FXAND in this population, our findings suggest that structured anamnesis and targeted questioning are crucial for its accurate detection. In other words, these symptoms can be identified only if data are collected carefully and systematically during clinical visits. Otherwise, retrospective data collection under less controlled conditions often leads to a loss of essential information on FXAND manifestations, thereby significantly underestimating their true prevalence.

This study, which relied on prospective data collection through a structured interview, revealed that female PM carriers frequently experience FXAND-related symptoms, including chronic pain, chronic fatigue, anxiety, and depressive symptoms. Regarding chronic pain, shoulder girdle pain is more prevalent among female carriers. Moreover, our findings demonstrated a clear association between anxiety/depressive symptoms and chronic fatigue. Notably, although no official diagnoses of anxiety, depression, chronic pain syndrome, unspecified chronic fatigue, or fibromyalgia were recorded among study participants, PM carriers nonetheless reported symptoms consistent with each of these conditions. The very absence of formal diagnoses among participants should serve as a strong incentive for clinicians to collect clinical data more carefully, as a warning sign that insufficient attention is currently being paid to this spectrum of PM-related conditions (Klausner et al., 2025; Montanaro et al., 2025).

Our findings demonstrate that chronic pain is significantly more prevalent among PM carriers than in the control group, with over half of PM carriers reporting chronic pain compared to only quarter of controls. In addition to higher prevalence, PM carriers also reported significantly greater pain intensity, particularly for activities such as brushing or combing hair. Moreover, pain levels in the PM group tended to increase with age. These findings are consistent with previous research demonstrating increased pain sensitivity and higher rates of chronic pain conditions such as fibromyalgia in PM carriers (reviewed in Tassone et al., 2023). Coffey et al. (2008) identified increased rates of fibromyalgia in PM carriers with definite or probable FXTAS, while those without FXTAS exhibited higher rates of muscle pain, defined as injury-unrelated myalgia lasting longer than 2 months (Coffey et al., 2008). Similarly,