Introduction 

Fragile X syndrome (FXS) is a genetic condition caused by a change to one of the genes on the X chromosome, where genetic material (DNA) is stored. FXS affects both people assigned male and female at birth and causes a range of physical, developmental and behavioural challenges.¹ It affects around 1 in 3600 men and between 1 in 4000-6000 women. FXS is also linked to features of autistic spectrum disorder.² There has been much attention surrounding the impact FXS has on cognitive and social development, but understanding its implications for reproductive health is equally important. In this article we will be exploring what Fragile X syndrome is, how it affects reproductive health, and considerations for individuals and families affected by the condition. 

What is Fragile X syndrome?

• Fragile X syndrome is caused by a mutation in the FMR1 gene that is located on the X chromosome³
• This mutation leads to a lack of protein Fragile X mental retardation protein (FMRP) production, which is essential for normal brain development³
• Without enough of this protein, individuals with FXS experience developmental challenges
• While FXS presents differently in every patient, some individuals may experience mild symptoms while others experience severe impairments³

Symptoms and causes of Fragile X syndrome

Fragile X syndrome can cause a range of physical, developmental, behavioural, and emotional difficulties in patients. 

Intellectual issues 

• Low IQ 
• Development delay which includes speech and communication difficulties
• Intellectual disability and learning difficulties
• Sensory difficulties 
• Language processing issues

Mental health disorders 

• Anxiety
• Depression 
• Obsessive-compulsive behaviours 

Physical features 

• Large prominent forehead 
• Narrow long face 
• Crossed eyes
• Large ears
• Flat feet
• Low muscle tone
• Large testicles in patients assigned male at birth

Behavioural issues 

• Attention Deficit Hyperactivity Disorder (ADHD)
• Behaviours similar to that of autistic spectrum disorder
• Poor eye contact
• Social anxiety 
• Shyness 

Causes of Fragile X syndrome 

• FXS is not a common disorder, affecting 1 in 3600 men and between 1 in 4000-6000 women ⁴
• It is estimated that 1 in 150 women and 1 in 800 men are carriers of this gene⁴
• While these individuals are only ‘Fragile X premutation carriers’ and don't have symptoms, they are at risk of passing on the changed FMR1 gene to their children⁵
• People who are Fragile X premutation carriers are at risk of developing health problems later in life. 
• Around 20% of female Fragile X premutation carriers experience reduced fertility or early menopause. This is called Fragile X-associated Primary Ovarian Insufficiency, or FXPOI⁶

Reproductive health implications 

A critical aspect of FXS concerning reproductive health is its inheritance pattern. The FRM1 genes are located on the X chromosome. Females have two X chromosomes (XX), while men only have one X chromosome (XY). The impact of FXS in females is usually less, due to the presence of the second X chromosome.

Fragile X-associated primary ovarian insufficiency

• Fragile X-associated primary ovarian insufficiency (FXPOI) affects women, leading to reduced ovarian function⁷
• Symptoms include irregular menstrual cycles, early menopause, infertility, and elevated levels of follicle-stimulating hormone (FSH)
• FSH regulates the development of reproductive cells in both males and females⁷
• Elevated FSH levels in younger women may indicate early menopause and fertility issues.
• FXPOI severity varies; some have overt primary ovarian insufficiency (POI) with irregular periods and elevated FSH before age 40, often causing infertility⁷
• Others have occult POI, with normal periods but reduced fertility and possibly elevated FSH levels⁸
• Reduced ovarian function due to FXPOI leads to low oestrogen levels, resulting in menopausal symptoms like hot flashes, insomnia, and osteoporosis⁸
• Women with FXPOI experience menopause around 5 years earlier than those without the condition⁸

Reproductive options and family planning 

Given the nature of FXS, individuals and families affected by the condition often face important decisions regarding family planning. Here are some things to consider:

Genetic testing

Genetic testing can be done to determine whether an individual is a carrier of the mutation FMR1 gene. This test provides valuable information for family planning and provides insight into the likelihood of passing FXS to future generations.⁹

Preimplantation genetic diagnosis 

Preimplantation genetic diagnosis (PGD) is a reproductive technology that allows embryos to be tested for genetic conditions before implantation during in-vitro fertilisation (IVF).¹⁰ Couples or individuals who are carriers of FXS can opt for PGD to select embryos that do not carry the mutated genes. 

Prenatal testing 

Couples who are already pregnant and at risk of having a child with FXS can conduct prenatal testing like chorionic villus sampling (CVS). This is where a healthcare provider takes a sample of cells from the placenta for testing, which can be used to detect the presence of the mutation in the foetus.¹¹

Adoption 

Couples or individuals may wish to find alternative ways to start a family. Adoption is a way around this, which means they cannot pass on the FXS gene to their children. 

Support and resources 

Getting diagnosed with FXS can be very overwhelming for individuals and families. It's important to remember that there are support groups, networks, and resources available to navigate the challenges associated with the condition.

Genetic counselling 

Genetic counsellors are trained professionals who can provide information and support regarding the inheritance and implications of FXS. They can assist individuals and families in understanding their options for family planning and reproductive health.¹²

Early intervention services 

There are early intervention programs that offer support and services to children experiencing developmental delays or disabilities, including children with FXS. These services can help children reach their full potential by addressing their developmental needs as early as possible.¹

Special education services 

Individuals who have FXS can benefit from special education services that are tailored to their specific needs. These services include individualised education plans (IEPs) and access to speech and occupational therapy.¹²

Support groups 

Navigating FXS can be quite hard. It's important to seek advice and support from loved ones and support groups that can provide a sense of community and understanding.¹ 

Summary

Fragile X syndrome presents unique challenges, including implications for reproductive health and family planning. Understanding the genetic basis of the condition and available options for testing and intervention is essential for individuals and families affected by Fragile X syndrome. By accessing support and resources, individuals with Fragile X syndrome can lead fulfilling lives, and families can make informed decisions about their reproductive health journey.