How common is Timothy syndrome? Management recommendations

Timothy syndrome is very rare. It was first reported in the Children with Timothy syndrome should be under the medical literature in 1995 but it took many years for the care of a multidisciplinary team including a cardiac gene responsible to be identified. Currently (2020) less specialist. than 100 children with TS have been reported in the Care for the type of anesthesia should be considered medical literature. It is expected that many more during a surgery. Cardiac and glucose monitoring is children will be diagnosed with this condition over the highly recommended throughout surgery and recovery following years as awareness of the syndrome increases. periods.

Early intervention with physical and speech therapies, Why did this happen? as well as social integration may be beneficial.

When children are conceived, the genetic material is Increased magnesium intake may be helpful for bowel copied in the egg and sperm that make a new child. The movements and also for migraine headaches which biological copying method is not perfect, and occasionally can also be problematic. random rare changes occur in the genetic code of children that are not seen in the DNA of their parents. Inform Network Support This happens naturally and is not due to any lifestyle, Rare Chromosome Disorder Support Group, dietary or environmental factors. No one is to blame The Stables, Station Road West, when these changes occur, and nobody is at fault. Oxted, Surrey. RH8 9EE. UK. Timothy syndrome Tel +44(0)1883 723356 In most children with Timothy syndrome diagnosed so [email protected] far, the change in the CACNA1C gene occurred by chance www.rarechromo.org CACNA1C in the child (this is known as de novo ) and was not found Websites, Facebook groups and other links: in their parents. However, a few parents have been found Website: https://timothysyndrome.org.uk/ Facebook: Timothy Syndrome and LongQT 8 - support group to carry a pathogenic CACNA1C gene variant in a few, but not all, of their cells (this is known as mosaicism) and it Timothy Syndrome Alliance (TSA) is a Registered Charity in England (Number 1185523) dedicated to means the variant can be passed on to their child(ren). the support of Timothy Syndrome and all other deleterious CACNA1C gene change families through Can it happen again? education, shared experience and research.

The risk of having another child affected by a rare gene Join Unique for family links, information and support. Unique is a charity without government funding, existing entirely on disorder depends on the genetic code of the parents. If donations and grants. If you can, please make a donation via our the change in the CACNA1C gene has been shown to be website at www.rarechromo.org/donate Please help us to help you! de novo, that means neither parent was found to carry it, This information guide is not a substitute for personal medical the chance of having another child with TS is low (less advice. Families should consult a medically qualified clinician in all than 1%). It is possible to have further children with matters relating to genetic diagnosis, management and health. Timothy syndrome if a parent is found to be for Information on genetic changes is a very fast-moving field and while the information in this guide is believed to be the best available at the CACNA1C gene variant. A clinical geneticist can give the time of publication, some facts may later change. Unique does you specific advice for your family. its best to keep abreast of changing information and to review its published guides as needed. This booklet was compiled by Can Timothy syndrome be cured? Katherine Timothy, the Timothy Syndrome Alliance (TSA) and Unique (AP) and reviewed by Katherine Timothy.

Version 1 (AP) Timothy syndrome cannot be cured at the present time. Copyright © Unique 2020 However, knowing the diagnosis means that appropriate rarechromo.org Rare Chromosome Disorder Support Group Charity Number 1110661 monitoring and treatment can be put in place. Registered in England and Wales Company Number 5460413 What is Timothy syndrome? Medical concerns Development

Timothy syndrome is a rare genetic condition that Most children with Timothy syndrome have :  Physical development causes a spectrum of complicated health concerns.  Abnormal heart (cardiac) function specifically Children with Timothy syndrome show delays in So far, most children with Timothy syndrome have been associated with an unusual electrical activity. reaching physical milestones such as walking, running found to have an abnormal heart function as well as The heart takes longer to ‘recharge’ between and jumping. developmental delays. Children with this syndrome can beats (this is known as a prolonged QT interval)  Intellectual development and learning have additional features including a weak immune which can lead to an irregular heart beat rate or Some Timothy syndrome children have been diagnosed system and dysfunction of the endocrine system rhythm () with mild to moderate learning difficulties and have (glands that secrete hormones).  Abnormal heart structure [including PDA (Patent special educational needs. Timothy syndrome is named after Katherine Timothy Ductus Arteriosus), TOF (Tetralogy of Fallot),  Speech and language who described the syndrome. ASD (Atrial Septal Defect), VSD (Ventricular Significant speech delays are common and receptive Septal Defect) and others] What causes Timothy syndrome? speech is generally more advanced than expressive  Neuronal developmental delays including speech. physical, social and mental difficulties. These Timothy syndrome is caused by Chromosome  Behaviour include ASD ( spectrum disorder), ADD specific changes (known as Social development is generally impaired, most (Attention Deficit Disorder), ADHD Attention pathogenic variants) to a gene children with Timothy syndrome are shy but a few are Deficit Hyperactivity Disorder), OCD (obsessive called CACNA1C. CACNA1C is an overly friendly. A few children have been diagnosed with compulsive disorder), schizophrenia and others abbreviation of the gene’s full neurodevelopmental disorders such as autism. name, ‘L-type Cell  Immunodeficiencies (that may result in frequent DNA respiratory, bronchial and laryngeal infections) Cav1.2’ which is a description of Timothy syndrome types 1-3 the gene’s function.  Endocrinological dysfunction (including Gene pancreatic, adrenal and thyroid concerns) Calcium channels are important Timothy Syndrome is caused by different genetic for movement of calcium into many of our body’s  Affected smooth muscle including variants of the CACNA1C gene and three different types different cells which in turn activates numerous gastrointestinal issues (constipation is common) of TS have been characterized accordingly. important processes.  Affected skeletal muscle including low muscle TS1 - often identified at birth if an infant presents with tone (hypotonia) The CACNA1C gene is located at the end of the short ‘p’ serious cardiac concerns and . A genetic test arm of in a region called 12p13.33.  Facial anomalies, hand and foot syndactyly identifies an change of G406R, in exon 8A of (when two or more fingers or toes are fused) CACNA1C.

CACNA1C Chromosome 12  Mild dental, skin, eye and/or hair anomalies TS2 - often identified at birth if an infant presents with

p13.33 Some children with Timothy syndrome have : very serious cardiac concerns, and often hypotonia, but

 Significant episodes of low blood sugar levels no syndactyly or other physical anomalies. A genetic p-arm q-arm (hypoglycemia) particularly associated with test identifies an amino acid change of G406R in exon 8 We have two copies of chromosome 12 in our cells, so (not 8A). infections and long periods of time without food. we also have two copies of the CACNA1C gene. TS3 - is the atypical form of Timothy syndrome (ATS), (A nighttime snack before bed is recommended, Timothy syndrome occurs when only one copy of the and fasting for greater than 10 hours is highly often identified at birth if an infant presents with a CACNA1C gene is affected, this is known as autosomal discouraged. During illness, regular intake of multisystem health concern that mostly, but not always, dominant since the change occurred on an autosome sugar rich fluids is recommended). includes cardiac and hand anomalies. A genetic test (this means any of our chromosomes numbered 1-22  Seizures (sudden and abnormal electrical identifies a pathogenic variant of the CACNA1C gene and does not include chromosomes X and Y that different to the TS1 and TS2 causing genetic variants. activity in the brain) determine biological sex) and features are apparent  An unusually low body temperature Any child suspected of TS should have their CACNA1C when only one copy of the gene is altered (dominant). (hypothermia) gene fully sequenced to determine which type of TS they have.