Chromosomal Abnormalities

  • Many forms of congenital heart disease are associated with an increased risk of chromosomal or genetic problems. Everybody has 23 pairs of chromosomes in each cell- one pair of which determines whether we are male (XY ) or female (XX) and the rest which determines the genetic make up of the body. Chromosomes are inherited from both parents and carry parental genetic information in the form of genes from generation to generation.

    There are many different types of chromosomal and genetic disorders. Some of these are able to be detected antenatally by undertaking an invasive test called a CVS (chorionic villus sampling) or amniocentesis depending on what stage of the pregnancy you are at.

    Detailed information leaflets about CVS and amniocentesis can be found on the Fetal anomaly screening programme website (FASP)

    CVS- fetalanomaly.screening.nhs.uk/getdata.php?id=11086
    Amniocentesis – fetalanomaly.screening.nhs.uk/getdata.php?id=11430
    There are many websites and support groups for families affected by different genetic problems and you may find some of the following useful both for information and for support.

    These are by no means exhaustive but are reliable sources of information.

    DiGeorge Syndrome

    DiGeorge Syndrome is also known as 22q11d and is a genetic disorder caused by a deletion/small missing segment of chromosome 22.
    It is a common chromosomal disorder and can be tested for during pregnancy with either Chorionic Villus Sampling (CVS) or Amniocentesis. Otherwise a diagnosis can be made after birth. In the majority of cases there is no family history. Only 10% of cases are inherited from a parent.
    DiGeorge syndrome has the potential to affect almost every system in the body and can cause a wide range of health problems. Though not always present the key characteristics of this syndrome include combinations and varying degrees of:
    Distinct facial features. (Low set ears, widely set eyes, a relatively long face, Small teeth and lower jaw).
    Congenital Heart Disease. Kidney problems. Feeding and gastrointestinal difficulties. Immune system deficiencies. Hearing loss. Low calcium and other endocrine issues. Cognitive, developmental and speech delays. Behavioural, emotional and psychiatric differences (ADHD, ASD, Major Depression, Anxiety, Mood and Psychotic disorders such as Schizophrenia). Not all children with 22q11d have the same problems, there is a lot of variability. Some children do not experience problems or have very mild symptoms whereas others can have moderate or severe physical, developmental and behavioural problems. This is not something that can predicted before birth.
    There is a lot of support available to help children with DiGeorge Syndrome lead healthy and fulfilling lives, these include:
    Access to good healthcare – including a range of different specialists.
    Support for your child’s development – including speech and language therapy and physiotherapy.

    DiGeorge Syndrome or 22q11 microdeletion

    Downs Syndrome

    Downs Syndrome is also known as Trisomy 21 and is a genetic condition that typically causes some level of learning disability.
    It is usually caused by an extra chromosome no 21 in a baby’s cell. In most cases it isn’t inherited. It is simply the result of a genetic change in the egg or sperm. There is a small chance of having a baby with Downs Syndrome in any pregnancy, but the likelihood increases with the age of the mother.
    Downs Syndrome can be confirmed during pregnancy with an invasive test, either Chorionic Villus Sampling (CVS) or Amniocentesis. Non-invasive prenatal testing (NIPT) is also available but this is a private test and there is a cost for it.
    Common physical characteristics may include: Floppiness (Hypotonia). Eyes that slant upwards and outwards.
    A small mouth with a tongue that may stick out.
    Below average weight and length at birth.
    Their palm may only have one crease across it.
    Although children may share these characteristics they do not all look the same. They will look more like their family members than other children with Downs Syndrome.
    Children with Downs Syndrome have different personalities and abilities. They may be slower to learn skills like sitting, standing, walking and talking and often need more support as they grow, including extra help in school.
    There are some medical conditions more common in children with Downs Syndrome, these include:
    Problems with their hearts and/or bowel. Difficulty with hearing and/or vision.
    A higher risk of infections including blood conditions such a Leukaemia.
    Around 1 in 10 have Autism Spectrum Disorder (ASD) or Attention Deficit Hyperactivity Disorder (ADHD). The average life expectancy of a person with Downs Syndrome is 60 years and it is suggested that 50% will develop some form of Dementia.
    There is a lot of support available to help children with Downs Syndrome lead healthy and fulfilling lives, these include:
    Access to good healthcare – including a range of different specialists.
    Support for your child’s development- including speech and language therapy and physiotherapy.
    Support groups – such as The Downs Syndrome Association. (downs-syndrome.org.uk).
    With support many people with Downs Syndrome are able to have relationships, go to work, leave home and live largely independent lives.
    Down’s Heart group
    Down’s Syndrome Association

    Turners Syndrome

    Turner’s Syndrome is a female only genetic disorder that affects about 1:2000 baby girls.
    A girl with Turners Syndrome only has one normal X chromosome rather than the usual two. This happens randomly when the baby is conceived. It isn’t linked to the maternal age.
    Turners syndrome can be diagnosed during pregnancy with an invasive test, either Chorionic Villus sampling (CVS) or Amniocentesis. Otherwise a diagnosis can be made after birth.
    General features include –
    Short stature. (Growth therapy treatment suggested).
    A short, wide neck.
    A broad chest and widely spaced nipples.
    Arms that turn out slightly at the elbow.
    A low hairline.
    Mouth abnormalities which may cause teeth problems.
    A large number of moles.
    Small, spoon-shaped nails.
    A short fourth finger or toe.
    Associated health conditions can vary significantly between individuals and can include –
    Kidney and Urinary Tract problems (Recurring Urinary Tract Infections. High Blood Pressure).
    Hearing problems (Recurring middle ear infections. Premature hearing loss).
    Eye problems (Short sightedness. Cataracts. Droopy eyelids/Ptosis. A Squint/Strabismus).
    Coarctation of the Aorta (Specific heart problem).
    Attention and hyperactivity problems during childhood.
    Learning difficulties/Spatial awareness problems.
    Infertility (Assisted conception techniques such as egg donation and IVF may be recommended for women with Turners Syndrome who want to have children).
    Most girls with Turners Syndrome have a normal level of intelligence and can lead a relatively normal and healthy life. Life expectancy is slightly reduced, but it can be improved with regular health checks to identify and treat potential problems at an early stage.
    The Turners Syndrome Support Society is a UK based charity that provides information, care and support for families who have a diagnosis of Turners Syndrome.

    Antenatal results and choices

    Trisomy 13/18