Fragile X Syndrome

A Guide for Teachers

Suzanne Saunders

• Publisher: David Fulton Publishers
• Year: 2013
• eBook ISBN: 9781134102297
• Edition: 1
• Topic: Education
• Subtopic: Education General

Fragile X Syndrome is thought to be the most common inherited cause of learning difficulties. However many people have never heard of it and those who have, including many of the professionals who work with those affected by it, have little knowledge or understanding of the condition. This book brings up to date research with information and advice from teachers who are discovering, first hand, the best ways of educating children with Fragile X. It is much needed support and advice that will help teachers to understand the child with Fragile X and encourage maximum educational progress.
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While the book is aimed at teachers, it is also an excellent resource for parents, therapists and any professional working with a child who has Fragile X.

Chapter 1
What is Fragile X Syndrome?

Introduction

In the first chapter the medical aspects of fragile X are discussed in order to give the reader some background information that will help to understand the condition.

In reality the medical aspects of fragile X are extremely complex and the condition is not yet fully understood. Research continues across the world to discover what happens within the body when a person has fragile X, and knowledge is growing every year. The following information attempts to present current knowledge in a simplified way that will give the non-specialist a clear and understandable overview of the condition.

What causes fragile X syndrome?

It has been stated that fragile X is caused by a fragile site or partial breakage on the tip of the long arm of the X chromosome. In fact, at this point of the chromosome the coils of DNA which make up the genes have become unwrapped but this is so fine that it cannot be seen with an ordinary microscope. So why does this cause a problem? The reasons are actually very complex and still not fully understood. This explanation provides a simplified picture of what happens within the faulty gene.

In 1991, Verkerk et al. located the actual gene responsible for fragile X syndrome. They determined that the abnormal appearance of the tip of the chromosome occurs at the site of the gene Fragile X Mental Retardation – 1 (FMR-1). The FMR-1 gene has what may be called a ‘housekeeping function, helping other genes to organise their activity. It does this by producing a particular protein that helps other genes in their organisation. Thus it is thought to be a protein carrier and crucial for normal brain development (Freund, 1994). A study by Reiss et al. (1991) using magnetic resonance imaging found selective atrophy of a specific brain area in people with fragile X compared to the general population. It was thought that this was the result of the protein deficiency.

In individuals with fragile X, a change exists in the FMR 1 gene. In everybody, the gene contains a repeating chemical sequence of three bases. This is called the CGG repeat. In most people in the population, without fragile X, the gene contains up to approximately 50 repeats. In a person who suffers from fragile X, there are many more repeats of this sequence, possibly thousands. This causes a chemical change within the gene which effectively switches it off. Therefore, the gene no longer performs its usual function of producing a protein, and lack of this protein prevents normal brain development. Thus, fragile X is a condition of a deficiency of the protein coded for by the FMR 1 gene.

The number of CGG repeats also explains why some people obviously carry the fragile X faulty gene but do not suffer from learning disabilities. It has been found that if the number of repeats is between approximately 50 and 200, the individual will be a carrier for the condition and capable of passing it on to their children. They are said to have a pre-mutation. It is only when the number of repeats exceeds approximately 200 that the gene is inactivated and the person suffers the full consequences of the condition.

Inheritance and transmission of fragile X syndrome

It is known that fragile X is an inherited condition and that it can affect many members and generations of a family. However, while it is classified as following a pattern of X-linked inheritance as the mutation occurs on the X chromosome, it is clear that fragile X has an unusual pattern of inheritance and there are anomalies or unusual features of its transmission that are not all fully understood yet.

It is useful to begin, to review some of the basic facts of genetics that explain how most diseases are inherited.

Every individual inherits 46 chromosomes from their parents. These chromosomes are made from genetic material called DNA. The chromosomes are organised into 23 pairs and one of each pair comes from the mother and one from the father. Twenty two of the pairs are called autosomes, and one pair comprises the sex chromosomes. In females, the sex chromosomes consist of two Xs, and in males there is one X and one Y chromosome.

As females have only X chromosomes, they can only pass X chromosomes to their offspring. Males however, having an X and a Y chromosome, can pass on either of these. If they pass on their X chromosome, the resultant child will have two X chromosomes and will be female. If they pass on their Y chromosome, the child will have one X and one Y chromosome and will be male. Therefore it is the male who dictates whether the child is a boy or a girl.

If a mutation occurs on the X chromosome, the resulting condition is said to be X-linked. The fragile X mutation, as we have already seen, occurs on the X chromosome.

Under the normal conditions of X-linked inheritance certain occurrences may be expected:

• A female carrier will not usually display the symptoms of the condition because she will carry it on only one of her X chromosomes and the other ‘good’ chromosome will cover its effects. She will however be capable of passing it to her children.
• The condition cannot be passed from a man to his son, as he does not pass his X chromosome to him. He will however, pass it to all his daughters as he only has one X chromosome, the affected one, to pass on.
• A female who carries the condition will risk passing it to 50 per cent of her male children, while the other 50 per cent will be unaffected. She will risk 50 per cent of her female children being carriers whilst 50 per cent will be non-carriers.

As we have stated previously, while fragile X conforms broadly to the usual pattern of X-linked inheritance, there are also some unusual features.

The first anomaly concerns the fact that some males may not be affected by fragile X even when it has been passed on to them, but although they may be unaffected themselves, they are still capable of passing carrier status to their daughters.

The second concerns the fact that some women who carry the gene are affected by it themselves. They may experience learning, social and behavioural difficulties though the degree to which they are affected varies and they are not usually affected to the same degree as males. Thirdly, the condition tends to get more frequent in families and more severe with the passing of the generations. Finally, while considering the inheritance of fragile X, it is possible for the condition to appear in a family that had no knowledge of its existence in their genes. It is possible for it to be carried through many generations without anyone being aware of it and only when a child displays significant difficulties are tests carried out and the condition diagnosed. This can come as a complete surprise and shock to the family Genetic counselling following diagnosis is important.

Diagnosing fragile X

In the past, the only method of diagnosing fragile X was by cytogenetic analysis, i.e. examining a persons chromosomes under a microscope. This was fraught with difficulty for several reasons.

It was a major breakthrough therefore when, after the discovery of the gene, a new method of testing was developed. This involves testing a persons DNA and is done from a simple blood test. DNA testing is more sensitive, less time-consuming and more cost-effective than chromosome analysis.

Recent advances which are currently still at a research stage or in their infancy include:

• the development of a test using cells from the cheek, thus avoiding the need to withdraw blood;
• a test involving a prick on the thumb which could produce a few drops of blood to be smeared on a slide and stained to reveal the presence or absence of the protein that is normally made by the FMR 1 gene.

Testing for fragile X can also be done pre-natally by chorionic villus biopsy.

Given that testing for fragile X is now relatively accurate, quick and painless, and that fragile X is known a relatively common inherited cause of learning difficulties, it raises the question of whether some form of screening for the condition should be considered. Modell (1992) describes the findings of a Mencap medical advisory panel workshop which considered the possibility of large scale screening for fragile X. However, Modell states that it was not considered feasible or ethical at that time and that resources should be concentrated on diagnosing children currently known to be at high risk of having the condition, ie. those with learning difficulties, and offering counselling to their families. Slaney et al., (1995), suggested that special school registers could be used to define a population for testing, or a register of all children with Statements of Special Educational Needs. However as greater numbers of children with learning difficulties are being included in mainstream schools, either with or without Statements, these may not be sufficient. Slaneys study in Oxford showed that screening a selection of special school children with learning difficulties in one county was technically feasible, identified previously unidentified cases and was acceptable to families.

To diagnose or not to diagnose?

Some people hold the view that it is almost irrelevant, in educational terms anyway, to spend a lot of time and effort finding out ‘what’ a child has, when the emphasis should be on looking at the individual with his particular characteristics and helping him to develop the skills and abilities to lead as happy, fulfilling and productive life as possible.

Other people would take the view that knowing exactly what has caused a child to have the difficulties that he experiences is important, not least because this knowledge can enable parents to accept and understand their child’s limitations, and can enable professionals to offer the right help in the right way. Needless to say this is not a clear-cut argument and there are no right or wrong answers.

The following points outline the major advantages and possible disadvantages of diagnosis in the case of children with fragile X.

Advantages

• Parents and other family members are often very anxious to know why their child experiences the problems that he does. A diagnosis can bring them this understanding and help them to accept the problems that the child and the rest of the family have to live with.
• Some parents, especially those whose children are mildly affected, may have been told by doctors that there is nothing wrong with their child. To a parent who knows that there is, apart from being very frustrating, this can lead to the parents feeling that they are the problem and that it is their ‘bad’ parenting skills that have caused their child to be the way he is. A diagnosis can be a tremendous relief in these circumstances.
• From the child’s point of view, he can know that his difficulties stem from a genetic defect that he has acquired through no fault of his own. This may be of immense help to a child who struggles with difficulties without knowing why he experiences them or to the child who erroneously thinks that his problems are somehow his own ‘fault’.
• With a diagnosis, many parents feel released to grieve for the child they have not had, and through this, to come to terms with their child as he is. While they have no diagnosis, they live with the hope that the child may be ‘cured’ or grow out of his problems. Though the diagnosis may cause a loss of that hope, it can lead ultimately to acceptance of the truth and to their concentrating on helping their child with the life that he has.
• Once the child has a diagnosis, knowledge relating to that condition can be offered to the family and to other professionals who work with the child. This might relate to common characteristics of the condition, knowledge about what to expect in the future and knowledge based on experience about the best ways to treat or help or teach the child. In the case of fragile X, knowledge relating to the inheritance aspects of the condition can also be given.
• From the child’s point of view, it is good that parents and teachers have access to information that will enable them to be more understanding of the difficulties that he faces in his everyday life.
• Knowledge about the inherited nature of fragile X may lead to other family members being tested and found to have the condition. This may be of particular help to those who only experience mild symptoms, yet nevertheless have struggled with difficulties all their lives without knowing why. This may apply particularly to girls.
• Awareness of the inherited nature of the condition means that family members can have genetic counselling to give them knowledge and support regarding their reproductive options. They can have the advantage of knowing their own status as regards being a carrier of the faulty gene, likely transmission of the condition, and prenatal screening techniques. They can then have professional counselling as they make some of the most difficult and emotionally charged decisions of their lives and live through the consequences of these decisions. While this may not seem like an advantage for those who have to face the horror of making the decisions, they at least have the chance to make informed choices.
• Many support groups or parent groups, formed by people who have personal experience of a specific condition, exist to offer knowledge and support to parents. They can provide the one thing that no other group can offer, namely the support and understanding of people who are in similar circumstances and who can empathise with the particular problems that a family is experiencing. This, coupled with the practical knowledge derived from having lived through it themselves, means that these groups can be of immeasurable help to those who might previously have felt that nobody else really understood what they were going through.

The address of the UK Fragile X Society can be found at the end of this book

• From the child’s point of view a local branch of a support group may offer him the chance to meet other people like him and to mix socially with them. Children with disabilities in our society can be very isolated, often having little or no social life of their own beyond the family. This can get more marked as they approach adolescence when parents may be re-establishing their own lives, getting older themselves and not doing the things that a young person wants to do. The child himself may not want to socialize with his parents, and siblings may be unable or unwilling to include their disabled brother or sister in their social life. (NCH Action for Children, 1994).
• From the point of view of the child, he may be able to accept himself better by understanding his limitations, and grow in self-esteem by learning new skills, meeting new challenges and making a worthwhile life for himself.

Disadvantages

• Initially at least, parents are likely to feel tremendous guilt stemming from the fact that one of them, always the mother in the case of fragile X, has passed on this condition to their child, however unwittingly. The parent who has actually passed on the gene is obviously likely to feel the most guilt, but as a child is the product of the union of two people, both often feel guilty.
• Grief. Both parents particularly, but also siblings, grandparents and the wider family must face the reality that this child will be disabled for life and may not fulfil the hopes and dreams that are held for him. Support or help for them as they work through this grief is crucial.
• The partner or other members of the family who do not carry the faulty gene may feel resentment at the partner who has brought it into the family. In unresolved cases this can lead tragically to the breakdown of a marriage that might already have been under pressure arising from the strain of raising a child with disabilities.
• The wider family may resent the fact that these particular members have brought a distressing family condition out into the open and made them all aware of it. While this is totally unreasonable as the condition will have been present but undetected for generations, it is not an uncommon reaction.
• Genetic testing will be undergone by family members providing they give their consent. Having tests and waiting for results will inevitably be extremely stressful for all concerned. Results can also cause friction within families.
• Fear for the future. Learning that your child has an incurable condition that he must live with for life and that other family members will be affected can be terrifying. Parents wonder how they will cope with the consequences of this new knowledge both in the short and long term and how the family unit will manage.
• Fears about how the child will manage in adult life, especially when the parents cannot be there to support him, must also be faced.

Treatment

There is currently no cure for fragile X syndrome. Once a child has been born with the condition it is present for life and the emphasis in treatment is on helping individuals to fulfil their potential despite the handicapping aspects of their condition.

At present, in the absence of a cure, treatment focuses on alleviating the symptoms of fragile X and on educating individuals and their families to understand the condition, mi...

Table of contents

• Cover
• Title
• Copyright
• Contents
• Introduction
• 1 What is Fragile X Syndrome?
• 2 The Child with Fragile X at School: Characteristics
• 3 Creating a Conducive Classroom Environment
• 4 Teaching Strategies
• 5 Social and Behavioural Development
• 6 Understanding the Family with Fragile X
• References
• Index