Information for health professionals

Transcription

1 Introduction of a new screening test for newborn babies in Wales Newborn bloodspot screening for Medium chain acyl-coa dehydrogenase deficiency (MCADD) Newborn bloodspot screening for MCADD is being introduced in Wales as recommended by the UK National Screening Committee. Available at: (accessed on ) Start date: 1 st June 2012 Babies who have their newborn bloodspot sample taken on or after 1 st June 2012 will be offered screening for MCADD in addition to screening for congenital hypothyroidism, cystic fibrosis and phenylketonuria. 1. Why are we starting to screen for MCADD? Babies with MCADD, an inherited metabolic condition, have problems breaking down fats to make energy for the body. This can lead to serious illness, or even death. Screening means that most babies who have MCADD can be recognised early, allowing special attention to be given to their diet, including making sure they eat regularly. This care can prevent serious illness and allow babies with MCADD to develop normally. Screening babies for MCADD is important, so those with the condition can be identified before they become suddenly and seriously ill.

2 2. What is MCADD? MCADD is an autosomal recessive inherited condition which affects about one in 10,000 babies born in the UK. It is estimated that three or four babies in Wales are born with this condition each year. MCADD is caused by a deficiency in the enzyme medium chain acyl- CoA dehydrogenase which is required for the breakdown of certain stored fats (medium chain fatty acids) to make energy for the body. Fatty acids are an important energy reserve during periods of poor calorie intake, prolonged periods between meals or during infections and sickness. The enzyme medium chain acyl-coa dehydrogenase enables the body to use these fat reserves to produce energy. Deficiency of medium chain acyl-coa dehydrogenase causes a block in the medium-chain length step of fat breakdown. This leads to a build up of medium-chain fatty acids, in particular octanoyl carnitine (C8) and its metabolites and results in inefficient breakdown of fat. As a result of not being able to use their fat reserves, children with MCADD quickly use up glucose and may develop hypoglycaemia. The high levels of partially broken down fatty acids and low blood glucose concentrations can result in metabolic crisis, with serious life threatening symptoms including drowsiness, seizures, brain damage and even death. MCADD can cause death at the first episode of metabolic crisis experienced. The mean age of a baby at this first presentation is 13 months and there is a 25% mortality rate. Affected children are usually well until potentially life threatening symptoms become apparent. Metabolic crises can arise during periods of stress caused by an illness, fasting or vomiting, when the child needs to break down fat quickly. 3. How are babies screened for MCADD? Screening for MCADD is carried out as part of the newborn bloodspot screening which also includes the tests for congenital hypothyroidism, cystic fibrosis and phenylketonuria. No additional blood sample is required. The sample (four bloodspots collected onto a newborn Page 2 of 6

3 bloodspot screening card) is taken five to eight days after birth, ideally on day five (counting day of birth as day 0). Levels of octanoyl carnitine (C8) are measured in the blood using tandem mass spectrometry. Babies with mean C8 levels above a defined cut-off are referred the same day to a paediatrician and to a specialist metabolic team. The screening test results are recorded as MCADD - Not Suspected or as MCADD Suspected 4. How do the parents receive the results? If MCADD is not suspected, the parents will receive the results in the same way as they receive the normal results for the other newborn bloodspot screening tests. These results will be available within six to eight weeks of the sample being taken, and will be given to the parents by the health visitor. If MCADD is suspected, the parents will be contacted by a designated local paediatrician on the same day as the result is obtained. The first contact with the parents will be verbally by telephone to explain the situation, to give them initial medical advice, to reassure and to arrange a face to face meeting either the same day or the next day with the paediatrician. The paediatrician will liaise with the GP and Health Visitor. 5. How is MCADD managed? Immediate management of babies if MCADD is suspected A baby suspected of having MCADD following newborn bloodspot screening will be referred by the Wales Newborn Screening Laboratory to be seen by a paediatrician and specialist metabolic team. An appointment will be arranged for the baby to be seen by a clinician within 24 hours. The baby will need diagnostic tests to confirm that they are affected by MCADD. Page 3 of 6

4 Long-term management of babies diagnosed with MCADD Babies with MCADD will receive care from a specialist metabolic team comprising of consultant inherited metabolic disease paediatrician, paediatric dietician with metabolic expertise and a clinical nurse specialist. The metabolic team will provide the parents of babies with MCADD information to help them manage the condition, and will continue to see the baby at regular intervals as they grow up. The management of babies with MCADD focuses on avoiding metabolic crises by the adherence to a regular safe feeding schedule, and the active management of febrile illnesses or vomiting. Babies with MCADD who are well can be fed normally: either breast feeding or normal infant formula every three to four hours. However, it is important babies do not fast for longer than six hours (day or night). Older babies may be able to fast for a longer time if it has been established that the safe interval between feeds can be lengthened. The metabolic team will advise on how often a baby should eat as they gets older. Children with MCADD can be on a normal, healthy diet. When the child is well, there is no specific dietary management apart from avoiding long periods without food. If a baby or child is unwell and/or is not feeding well, very frequent feeds or drinks of glucose polymer need to be given. This is called the Emergency Regimen. Glucose polymer will provide energy and help prevent the body fat stores being used for energy. If the emergency regimen is not tolerated by the baby or child, they will need urgent treatment including IV dextrose in hospital. If there is any doubt at all, a child with MCADD must be sent to hospital. With early detection and monitoring and avoidance of fasts, children diagnosed with MCADD can lead normal lives particularly as the safe time between meals expands as they grow older. They are also expected to have a normal life span. Page 4 of 6

5 6. Where can parents get further information about MCADD? Prior to screening parents can obtain information about MCADD from the Newborn Bloodspot Screening: Information for parents leaflet. This will be available to give to parents from 1 st June A leaflet has been developed for parents whose baby is suspected to have MCADD. The MCADD is suspected leaflet is available on the website Parents of babies who are suspected of having MCADD can also get further information from CLIMB Children living with Inherited Metabolic Diseases. This is registered charity and provides an information resource and support to parents. They can be contacted via their website: or by telephone: Where can health professionals get further information about MCADD? Further information is available at: Does screening for MCADD affect the care pathways for unwell newborn babies? Newborn bloodspot screening is undertaken on day five and if a baby develops symptoms before the results are known, MCADD needs to be considered as a possible cause. Any baby who is showing signs of hypoglycaemia should be referred promptly as per local hypoglycaemia policy to a paediatrician. Testing for MCADD should be carried out as part of the hypoglycaemia screening. 9. Should screening for MCADD be offered for babies who have had a newborn bloodspot sample taken before 1 st June 2012? Screening for MCADD is not offered for babies who have had newborn bloodspot screening before 1 st June Page 5 of 6

6 10. What should happen if there is a family history of MCADD? There is a chance of a new baby having MCADD if a sibling or other family member has the condition, and it is important that early MCADD screening is offered. Pregnant women should be asked if they have any children who are known to have MCADD, or if they or the father of the baby have any family history of MCADD. The midwife should act on this information and refer to a paediatrician for advice and the development of a plan for the care of the baby following birth. This plan should be recorded in the maternity notes. The midwife should also notify the Wales Newborn Screening Laboratory on telephone number , and in writing. The parents should be offered an earlier bloodspot screening test for their baby, specifically for MCADD, and appropriate advice should be given to the parents on care of their baby and maintaining a good milk intake. The early bloodspot sample (four bloodspots) for MCADD should be obtained hours after birth. Family history of MCADD should be recorded on the bloodspot screening card. Another sample should be taken for routine newborn bloodspot screening five to eight days after birth, preferably on day five (counting day of birth as day 0) to include the other screening tests. If a baby is found to have MCADD, older siblings born before newborn screening for MCADD started may be at risk of having the condition, even though they may have been asymptomatic to date. These older siblings should be offered testing for MCADD. This will be arranged by the metabolic clinician. Information provided with thanks to UK Newborn Blood Spot Screening Programme Centre ( Page 6 of 6