Overview

 Chromosomal abnormalities are defined as either a deviation from the normal number of chromosomes (a deletion or extra copy) or structure (when a part of a chromosome is deleted, duplicated, inverted or translocated causing a structural change).¹

One such numerical chromosomal abnormality is Klinefelter syndrome. It is one of the most commonly occurring abnormalities (1 in 500 to 1000 babies who are assigned male at birth (AMAB)). Klinefelter syndrome can cause multiple issues related to physical, developmental, behavioural and reproductive features.² Read on to know more about the details of causes, symptoms and management options for individuals with Klinefelter syndrome.

What is klinefelter syndrome? 

Klinefelter syndrome is a genetic condition that occurs when an AMAB baby is born with an extra X chromosome. Normally, AMAB individuals will have 46 chromosomes (44 autosomes + 2 sex chromosomes (XY)), but individuals with Klinefelter syndrome have 47 due to an additional X chromosome. Therefore their genotype is not XY as normal, but instead XXY.³ 

This genetic condition is not inherited from parents; instead, it occurs as a random error during the process of formation of reproductive cells (eggs and sperm) called meiosis^.4 As a result, an extra X chromosome is present in all or most of the cells of the body.

Affected individuals usually have a male reproductive anatomy and genitalia despite the presence of an extra X chromosome. However, the typical characteristic symptom associated with Klinefelter syndrome is infertility due to underdeveloped testes and subsequently reduced testosterone production.⁵ Therefore, these individuals are categorised as intersex; having characteristics of both sexes.

Symptoms of klinefelter syndrome in children

Many individuals with Klinefelter syndrome do not present any major or prominent symptoms until later in life when they are diagnosed with infertility and undergo DNA karyotyping. Individuals without problematic symptoms or infertility may never receive a diagnosis. 

Below are some common physical, developmental and behavioural symptoms developed in children with Klinefelter syndrome. However, we should keep in mind that not all children exhibit all symptoms and the degree of severity can vary from infancy to adolescence and also among children. Children are likely to present symptoms more apparent during puberty and adolescence due to hormonal changes.

Physical symptoms^6,7

• Growth abnormalities - tall stature during childhood and adolescence
• Disproportionate body  - e.g., long limbs and short torso
• Gynecomastia - the development of breast tissue in boys during puberty due to elevated oestrogen and reduced testosterone 
• Small testes that may not descend or develop fully and that produce lower levels of testosterone
• Delayed puberty and late onset of secondary sexual features - sparse facial hair growth, female pattern of pubic hair growth, and no deepening of the voice
• Infertility due to underdeveloped testes and reduced testosterone production may require assisted reproductive technologies if they desire  children in the future
• Reduced muscle mass and strength 
• Skeletal abnormalities such as reduced bone density or joint problems
• Distinct facial structures such as a round face, narrow chin, and prominent forehead

Developmental delays

• Speech and language delays - difficulties in expressing feelings, reading, and comprehension
• Motor skill difficulties - delays in performing both gross (walking, running, and jumping) and fine (writing, buttoning clothes, and using utensils) motor skills
• Cognitive challenges - attention, concentration, memory, problem-solving skills, planning, decision-making, and self-regulation
• Learning disabilities - difficulties with reading, writing, maths, processing information, and execution
• Difficulty performing everyday tasks independently - dressing, grooming and hygiene, time management, and organisational skills

Behavioural and emotional symptoms

• Social difficulties - struggling to interpret social cues, maintain relationships, peer rejection, and loneliness
• Anxiety disorders - excessive worry, fear, and nervousness
• Depression - persistently feeling sad, hopeless and having low levels of motivation
• Behavioural problems - hyperactivity, attention deficit, trouble being organised and following instructions
• Emotional sensitivity - being emotionally reactive and prone to emotional outbursts, frustration, or mood swings
• Self-esteem issues - issues related to self-confidence due to physical appearance, academic performance, and social interactions

Diagnosis of klinefelter syndrome in children

A comprehensive evaluation plays a significant role in providing an accurate diagnosis of Klinefelter syndrome and differentiating it from other chromosomal abnormalities that may present with similar symptoms. The diagnosis process of Klinefelter syndrome involves clinical evaluation, genetic testing, hormonal screening and imaging as follows:

Clinical evaluation 

The first thing to do when any symptom shows up is generally to visit a healthcare provider or paediatrician. They will thoroughly review the child's medical history, conduct a physical examination, and assess the signs and symptoms to see if they align with those seen in Klinefelter syndrome such as tall stature, gynecomastia, small testes, and developmental delays.¹⁰

Genetic testing

If the primary clinical evaluation is suggestive of Klinefelter syndrome, the next step is to perform genetic testing to provide a definitive diagnosis. Genetic testing involves karyotyping, which is the analysis of the number and structure of chromosomes from the child's blood or tissue sample. In the case of a positive result, the test will reveal the karyotype to be XXY.¹¹

Hormonal evaluation and imaging

Hormonal testing of children involves measuring levels of testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and other hormones involved in reproductive function. Furthermore, ultrasound imaging may be performed to determine the size and structure of the testes in children. Small testes, low testosterone, and high LH and FSH levels are common in children with Klinefelter syndrome due to testicular dysfunction.¹² 

Psychological assessment

It is important to evaluate the cognitive abilities, behavioural functioning, and social-emotional development of children with suspected Klinefelter syndrome.¹³ This assessment can help in the early identification of any developmental delays, learning disabilities, or behavioural challenges that require tailored intervention.

It is crucial to identify the syndrome at the earliest opportunity to address the developmental challenges appropriately. This helps to tailor the required interventions to the child. This also prevents complications and maximises the potential for social, emotional, and academic outcomes in children.

Treatment and management

Currently, there is no cure available, however, there are plenty of treatment and management options which are beneficial for children growing up with Klinefelter syndrome. 

Hormone replacement therapy

Hormone replacement therapy is often recommended in children through injections, topical gels, or patches to compensate for the low testosterone levels. This supplemented testosterone aids in developing muscle mass, bone density, and the masculine changes associated with puberty.¹⁴ 

Educational and behavioural interventions

Academic performance can have a heavy impact on children's confidence and self-esteem. Individualised education plans and special accommodations in the classroom to support their unique learning needs may significantly improve the outcome in children with Klinefelter syndrome. 

Similarly, behavioural interventions and social skills training can help the affected children who face attention-deficit problems and improve self-regulation, interpersonal skills, and emotional well-being.¹¹

Fertility options and reproductive counselling

Children with Klinefelter syndrome will face infertility during adulthood. Therefore, during adolescence, fertility counselling may be provided to inform the patient of the currently available options for sperm retrieval and assissted reproduction.¹⁵

Speech and occupational therapy

Many children with speech delays can benefit from speech therapy interventions. Individualised speech therapy sessions tailored to the child's communicating ability help to promote their expressive language, interpreting skills, and overall communication.

In addition to speech therapy, occupational therapy can help to develop fine motor skills in affected children and improve coordination which will eventually make them independent in day-to-day self-care activities.

Psychological and social support

Psychological counselling can help both the children with Klinefelter syndrome and their families to deal with any difficult emotions and understand how to manage and diagnose. It also helps to address the underlying concerns, anxiety and social adjustment issues in the family.

Enrolling the affected children for regular medical follow-ups will aid in monitoring their progress over time. This includes regular reviews of the child’s physical growth, development, and hormone levels and allows for early identification of any potential complications. Collaborating with relevant support groups creates opportunities to meet people with similar challenges and can help with insecurities and feelings of loneliness.

Overall, appropriate care and support mean that children with Klinefelter syndrome can lead long, healthy, and fulfilling lives.

Summary

Klinefelter syndrome is a chromosomal abnormality that occurs when a baby assigned as male is born with an extra X chromosome (karyotype = 47, XXY). Affected children may exhibit a range of physical, developmental, cognitive, behavioural and emotional symptoms, of which delayed puberty and infertility are the most typical. Early identification and a multidisciplinary approach to medical treatment and psychological management can help improve outcomes and quality of life for children with Klinefelter syndrome.