Dr. Alessandro Giardini
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When someone in the family has been diagnosed with an inherited heart condition, parents naturally worry about their children. The same concern arises when a young relative has died suddenly and without explanation. These worries are entirely reasonable, and they deserve a clear answer.
The reassuring starting point is this: most children who attend family cardiac screening turn out to be completely well. Screening exists not to frighten families but to find the small number of children who carry a genuine risk, so that monitoring, treatment, or lifestyle guidance can begin before problems develop. For most families, the outcome is certainty and reassurance. For a few, early detection is genuinely life-saving.
I assess children referred for cardiac family screening across the full range of inherited conditions, including cardiomyopathies, inherited arrhythmia syndromes, aortic and connective tissue conditions, and familial high cholesterol.
Cardiac family screening is the systematic assessment of children who may be at increased risk of a heart condition because of their family history. It begins with first-degree relatives: parents, brothers, sisters, and children of the person with the confirmed diagnosis. If a finding is made, screening extends further through the family. This process is known as cascade screening.
NHS England inherited cardiac condition guidance recommends offering screening to first-degree relatives when an index case is identified, then cascading to others depending on findings. When the affected relative carries a known disease-causing gene variant, targeted genetic testing in children can determine who has inherited the mutation and who can be safely discharged.
Many inherited heart conditions produce no symptoms at all during childhood. A child may feel perfectly well, pass routine medical examinations, and play sport without difficulty, yet carry a genetic change that could eventually cause serious harm. Relying on symptoms alone is not a safe strategy. Proactive screening addresses that gap.
The following sections cover each group of conditions where a diagnosis in a parent or close relative should prompt cardiac assessment in children.
Cardiomyopathies are diseases of the heart muscle. Most follow autosomal dominant inheritance, meaning each child of an affected parent has a 50% chance of carrying the relevant gene variant.
Hypertrophic cardiomyopathy (HCM) causes abnormal thickening of the heart muscle walls. It is the most common inherited heart condition, affecting around 1 in 500 people. European Society of Cardiology guidelines recommend clinical screening of first-degree relatives from the age of 10, with earlier assessment when there is a family history of sudden death in young relatives, childhood-onset disease, or involvement in competitive sport. Recent evidence from specialist centres has shown that nearly 10% of children screened before the age of 10 already have echocardiographic evidence of HCM, with the median age of onset around 8 to 9 years. In my practice, I assess children of an affected parent without applying a rigid lower age cut-off when there is clinical concern, a competitive sport commitment, or a family history of early events. Screening includes an ECG and echocardiogram as first-line tests, with Holter monitoring, exercise testing, and cardiac MRI added as indicated. A normal result in childhood is reassuring but does not close the book: HCM can emerge or progress during the adolescent growth spurt, and repeat screening every one to two years through the teenage years is standard.
Dilated cardiomyopathy (DCM) causes enlargement and weakening of the heart. Around 30 to 50% of cases have a genetic basis, with over 50 causative genes now recognised. Children should be considered for screening when a parent or close relative has unexplained DCM, particularly if disease onset was young or more than one family member is affected. First-line assessment includes ECG and echocardiogram.
Arrhythmogenic cardiomyopathy (ACM), including ARVC, is a condition in which the heart muscle is gradually replaced by fatty or fibrous tissue, creating a risk of dangerous arrhythmias during exercise. It follows autosomal dominant inheritance in most cases and can remain clinically silent for years. Children need assessment when a parent or sibling carries a confirmed diagnosis, or when sudden death in a young relative may have been due to this condition. Screening typically includes ECG, Holter monitoring, exercise testing, echocardiogram, and cardiac MRI. Features can develop gradually over time, so repeat assessments at regular intervals are important.
Restrictive cardiomyopathy and left ventricular non-compaction are less common but can run in families. When a close relative carries one of these diagnoses, children may need assessment with ECG, echocardiography, and sometimes cardiac MRI or genetic testing.
In channelopathies, the heart looks structurally normal, but the electrical system is inherently unstable. These conditions are among the most important causes of unexplained sudden death in apparently healthy young people.
Long QT syndrome (LQTS) disrupts the electrical recovery phase between heartbeats, creating a vulnerability to a fast and potentially fatal arrhythmia. Triggers include exercise, sudden loud noises, emotional stress, and certain medications. Children should be screened when a parent or sibling has long QT syndrome, when there is a known gene variant in the family, or when unexplained fainting or sudden death has occurred in young relatives. International consensus guidelines from the Heart Rhythm Society and the European Heart Rhythm Association specifically support offering predictive genetic testing early in childhood, even in infancy, when a family mutation is known. This is because the result can directly change prescribing decisions and may lead to starting beta-blocker therapy. Tests include ECG, exercise testing, Holter monitoring, and genetic analysis.
Brugada syndrome carries a risk of ventricular fibrillation, particularly during fever. It follows autosomal dominant inheritance and mainly affects adult males, but screening of children is recommended when a parent or sibling has a confirmed diagnosis or pathogenic variant. Assessment includes standard ECG, high precordial lead placement, and genetic testing when a family variant is identified.
Catecholaminergic polymorphic ventricular tachycardia (CPVT) produces dangerous arrhythmias triggered by exercise or intense emotion, with a normal resting ECG and a structurally normal heart. It is one of the most underrecognised causes of exercise-related syncope and sudden death in young people. Children should be screened when a close relative has CPVT, exercise-triggered syncope with a confirmed cardiac cause, or sudden death during physical activity. The key diagnostic test is an exercise stress test, supported by ECG, Holter monitoring, and genetic analysis.
Short QT syndrome and other rare inherited arrhythmias are uncommon but important. Screening is guided individually by a specialist inherited cardiac conditions team.
This is one of the most urgent reasons to pursue cardiac screening in children. When a close relative died suddenly and unexpectedly, particularly under the age of 50 or during physical activity, children in the family should receive a specialist cardiac assessment even if they appear entirely well.
The most likely underlying causes of unexplained sudden death in a young person include channelopathies (long QT syndrome, Brugada syndrome, CPVT) and undetected cardiomyopathies (HCM, arrhythmogenic cardiomyopathy). Published data show that assessment of family members following a sudden arrhythmic death identifies at least one affected individual in up to half of families screened. From 2023, the NHS Genomics Testing Directory includes a provision for whole-genome sequencing following unexplained sudden death in infants and children in England, which can identify a genetic finding to guide family screening even when the post-mortem was inconclusive.
Bringing a copy of the death certificate and the post-mortem report, if one was performed, helps the clinical team focus on the most relevant tests.
Some inherited conditions primarily affect the aorta, causing progressive enlargement or an increased risk of aortic dissection. Identifying these early in children allows monitoring and appropriate physical activity guidance before complications develop.
Children may need screening when a parent or sibling has Marfan syndrome, Loeys-Dietz syndrome, vascular Ehlers-Danlos syndrome, familial thoracic aortic aneurysm or dissection, or unexplained aortic enlargement at a young age. Marfan syndrome affects roughly 1 in 5,000 people and follows autosomal dominant inheritance, with around one quarter of cases representing new mutations. Diagnosis relies on clinical assessment using the Ghent criteria, which combine cardiovascular, skeletal, ocular, and skin findings. Cardiac assessment includes echocardiography to measure the aortic root and ascending aorta, along with ECG. MRI or CT is used in selected cases. Eye examination and skeletal review are also part of the work-up. Children with an enlarged aortic root require regular monitoring and individualised activity guidance.
Bicuspid aortic valve is one of the most common congenital cardiac findings and can cluster in families. When a parent, sibling, or child has a bicuspid aortic valve, first-degree relatives are often advised to have an echocardiogram. The purpose is to check whether the valve is also bicuspid, whether there is associated narrowing or leakage, and whether the aorta is enlarged. Other left-sided obstructive conditions, including coarctation of the aorta, may also show familial clustering. Screening decisions depend on the specific diagnosis and family pattern.
Familial hypercholesterolaemia is an inherited condition causing very high LDL cholesterol from birth. It affects approximately 1 in 250 people and is significantly underdiagnosed. Without detection and treatment, FH carries a substantially elevated risk of coronary heart disease at a young age.
Children should be assessed when a parent has confirmed FH, a known FH gene variant, very high LDL cholesterol, or a history of heart attack or coronary disease before the age of 50. Testing involves a cholesterol blood test and, where a family variant is known, targeted genetic testing. The heart structure is usually normal in childhood. The purpose of screening is prevention of future coronary disease through early treatment, typically involving dietary guidance and, from adolescence, statin therapy. This differs from ECG-based cardiac screening, but it is equally important.
Most congenital heart defects do not follow simple Mendelian inheritance, but certain families carry an increased recurrence risk. Screening may be considered when a parent has congenital heart disease, when more than one child in the family is affected, when a known genetic syndrome is present, or when there is a family history of left-sided obstructive conditions. Echocardiography is the primary investigation in children. In pregnancies with a significant family history, fetal echocardiography at around 20 weeks of gestation can provide detailed assessment of the developing heart.
The tests required depend on the condition in the family. Not every child needs every investigation. The starting point is always a detailed family history and clinical assessment, which together determine the most efficient and informative pathway.
A thorough family history and family tree are the single most important first step. Knowing who is affected, what the precise diagnosis is, whether sudden death has occurred, whether symptoms related to exercise, and whether a causative gene variant is known allows the cardiologist to plan appropriately. Parents should bring clinic letters, genetic test results, and any post-mortem reports belonging to the affected family member.
Clinical examination may identify murmurs, blood pressure differences, features of connective tissue conditions, or signs suggesting a genetic syndrome. An ECG records the heart's electrical activity and is a quick, painless test that can detect long QT syndrome, Brugada pattern, Wolff-Parkinson-White syndrome, signs of cardiomyopathy, and conduction abnormalities. It is a first-line investigation in almost all family screening pathways.
An echocardiogram provides detailed information about the heart's structure and function, including muscle thickness, chamber dimensions, valve anatomy, and aortic size. It is the key test when screening for cardiomyopathies, aortic disease, bicuspid aortic valve, and congenital heart conditions.
A Holter monitor records the heart rhythm over 24 to 48 hours or longer and is used when there is concern about intermittent arrhythmias or fainting episodes. An exercise stress test assesses the heart's response to physical activity under supervised conditions and is central to the evaluation of CPVT, long QT syndrome, and arrhythmogenic cardiomyopathy.
Cardiac MRI provides detailed images of the heart muscle and is particularly useful in evaluating arrhythmogenic cardiomyopathy, identifying fibrosis in HCM or DCM, and assessing complex aortic anatomy. Genetic testing is most useful when a pathogenic variant has already been identified in the affected family member, allowing targeted testing of children to confirm or exclude the same mutation.
Genetic testing in children raises important questions that deserve thoughtful discussion with the family and, for older children, with the young person themselves.
Two types of genetic testing are relevant. Diagnostic testing is performed when a child already has clinical features of an inherited condition, aiming to confirm or refine the diagnosis. Risk-predictive testing is performed in a child who appears clinically well, to determine whether they carry a variant that causes disease in the family.
For clinical investigations such as ECG and echocardiography, parents provide consent for younger children. These tests carry no meaningful risk and have a clear clinical benefit. For genetic testing, the decision is more nuanced. International guidance supports offering predictive genetic testing early in childhood (in some conditions, even in infancy) when the result would directly change clinical management. Long QT syndrome is the clearest example: a positive result alters prescribing decisions, informs exercise guidance, and may prompt starting medication. Similarly, early testing is supported for CPVT and for aortopathies such as Marfan syndrome.
For conditions where a positive result in childhood would not immediately change management, and where problems typically arise only in adulthood, specialist guidance generally supports deferring predictive testing until the young person is old enough to make the decision themselves. This respects the ethical principle that individuals should retain the right to choose whether to know their genetic status.
I work closely with inherited cardiac conditions genetics teams to ensure each family receives appropriate guidance. Older children and teenagers should always be included in discussions about their own testing, given information in an age-appropriate way, and offered the opportunity for a private conversation with the clinical team if they wish.
Brothers and sisters of a child diagnosed with an inherited heart condition may need screening themselves, because most of these conditions follow autosomal dominant inheritance. Each sibling carries a 50% probability of having the same genetic variant.
Sibling screening is most clearly important when a disease-causing mutation has been confirmed, when the condition can cause harm during childhood, when the first presentation can be sudden and serious, when exercise restriction or lifestyle changes might reduce risk, or when the sibling participates in competitive sport.
Conditions for which sibling screening is indicated include HCM, DCM, arrhythmogenic cardiomyopathy, long QT syndrome, Brugada syndrome, CPVT, Marfan syndrome and other aortopathies, familial hypercholesterolaemia, and unexplained sudden death in the family. In certain patterns of congenital heart disease, sibling screening by echocardiography may also be recommended.
The timing and frequency of screening depend on the specific diagnosis, the child's age, and the initial findings. Some siblings need only a single assessment with a clear result. Others need repeat monitoring through childhood and adolescence because certain conditions develop gradually or emerge only during periods of growth.
One of the most important messages for families is that a single normal result does not always close the case. Several inherited cardiac conditions, particularly HCM and arrhythmogenic cardiomyopathy, can develop or worsen during periods of rapid growth.
Children with a family history of HCM and a normal initial assessment typically require repeat screening every one to two years through adolescence, then every three to five years in adulthood. For arrhythmogenic cardiomyopathy, similar intervals apply given the progressive nature of the disease. For channelopathies such as long QT syndrome and CPVT, the genetic test result carries particular weight: a negative result in a family with a known mutation usually allows discharge from ongoing cardiac surveillance. For aortic conditions, the frequency of monitoring depends on the degree of aortic enlargement.
If you are unsure whether your child is due a repeat assessment, please seek specialist advice rather than waiting for symptoms.
A normal result is good news and should be communicated clearly. It may mean the child has not inherited the family condition. It may mean they carry a genetic risk but have not yet developed signs. Or it may mean the family diagnosis does not relate to a heritable risk.
If a known pathogenic genetic variant exists in the family and the child tests negative for that variant, this result is generally highly reassuring and often allows discharge from routine cardiac surveillance. If no gene variant has been identified in the family, a normal ECG and echocardiogram is encouraging but may need repeating at intervals, because clinical expression can emerge with age. A clear explanation of what a normal result does and does not mean, in the context of your specific family history, is one of the most important parts of the consultation.
Identifying an abnormality before it causes symptoms is exactly what screening is designed to achieve. It should be understood as a positive outcome, not a crisis. Early detection allows monitoring, treatment, and lifestyle guidance to begin well before complications develop.
Depending on the finding, management may involve reassurance with regular review, medication, exercise guidance, avoidance of specific triggers or drugs, referral to a specialist inherited cardiac conditions service, or (in selected cases) more active intervention. The aim is always to keep the child safe while preserving as normal and active a life as possible.
A separate group of children require cardiac assessment not because of family history but because of their own underlying medical condition. These include children with Down syndrome, where congenital heart defects affect around 40 to 50% and echocardiography is recommended in the first month of life. Turner syndrome carries an increased risk of bicuspid aortic valve and aortic enlargement. Noonan syndrome is associated with pulmonary valve stenosis and sometimes HCM. Williams syndrome is linked to supravalvular aortic stenosis. Kawasaki disease requires coronary artery assessment because of the risk of coronary aneurysms. Duchenne muscular dystrophy involves progressive cardiomyopathy that typically develops from early adolescence. Children who have received anthracycline chemotherapy need long-term cardiac surveillance for treatment-related cardiomyopathy. Children with large segmental facial haemangiomas may need assessment for aortic arch abnormalities associated with PHACES syndrome. Persistent high blood pressure, unexplained exertional symptoms, or initiation of certain medications such as ADHD treatment may also warrant cardiac evaluation.
If your child needs a heart check for any of these reasons and you would like specialist assessment, I am happy to help.
Yes. Each child of a parent with HCM has a 50% chance of carrying the family gene variant. Clinical screening is recommended from around age 10, or earlier if there is a family history of sudden death in young relatives, if the child has symptoms, or if they play competitive sport. Published evidence shows that HCM can present before age 10 in a significant proportion of cases, so earlier assessment is reasonable when there is any concern. Screening involves at least an ECG and echocardiogram, repeated every one to two years through adolescence even when the initial result is normal.
In most inherited conditions, yes. When the affected child's diagnosis has a recognised inheritance pattern, brothers and sisters should be assessed. The type and timing of screening depend on the specific condition. For conditions that can cause problems in childhood, early assessment is important. For predominantly adult-onset conditions, the timing of genetic testing is discussed individually with the family and genetics team.
That depends on the condition. For HCM and arrhythmogenic cardiomyopathy, a normal result does not eliminate the need for repeat assessment, particularly through the adolescent growth years. For channelopathies where a known family gene variant exists and the child has tested negative, that single genetic result can be more definitively reassuring than years of repeated clinical tests. Ask your cardiologist whether further follow-up is recommended and at what interval.
Yes, and I would encourage you not to delay. When sudden death in a young person remains unexplained, the most likely underlying causes are inherited cardiac conditions, particularly channelopathies and cardiomyopathies. Assessment of family members following unexplained sudden death identifies an affected individual in up to half of families. Bringing information about the circumstances and any post-mortem findings will help the clinical team target the most relevant investigations.
Most initial assessments are straightforward and non-invasive. The appointment typically begins with a detailed discussion of the family history, followed by clinical examination, an ECG, and an echocardiogram. Depending on the condition being assessed, a Holter monitor, exercise test, or blood test may also be arranged. For most children, the process feels entirely routine. The most valuable part is often the conversation with the cardiologist about what the results mean.
This depends on the condition, your child's age, and whether a specific mutation has been found in the affected relative. Genetic testing is most valuable when a pathogenic variant is already known in the family. For conditions where a positive result would directly change childhood management (such as long QT syndrome or CPVT), early testing is supported by international guidelines. For other conditions, the timing of testing is discussed with the family on a case-by-case basis. Older children and teenagers are always involved in the decision. Genetic counselling is an important part of this process.
This depends on the family history. When there has been a sudden death during exercise, or when the family condition carries a known exercise-related risk (such as CPVT, HCM with obstruction, or arrhythmogenic cardiomyopathy), specialist advice should be obtained before continuing intense competitive sport. For most children awaiting routine screening because a parent has a diagnosed condition, moderate recreational activity is unlikely to pose significant risk. If you are uncertain, please contact a specialist rather than making assumptions.
Cascade screening is the process of systematically testing relatives of an affected individual, starting with the closest family members and extending outward based on results. When a pathogenic gene variant is identified in the affected person, each relative can be tested for that specific variant. Those who test negative can often be discharged from cardiac surveillance. Those who test positive receive the same comprehensive clinical assessment. In large families, this process may identify multiple affected individuals who would otherwise have remained undetected for years.
A borderline result means that a measurement (such as heart muscle thickness or QT interval) falls above the normal range but does not yet meet full diagnostic criteria for the condition being considered. This is a recognised scenario in family screening, particularly in younger children and during the early stages of a condition that may progress with growth. Borderline findings usually require repeat assessment at a defined interval and close clinical follow-up. They do not necessarily mean your child has the condition, but they do mean monitoring should continue.
Author: Dr. Alessandro Giardini, MD, PhD
Written 02/05/2026