metabolic disorders 1 Flashcards
Describe the NBS (newborn blood spot or heel prick test) screening programme.
It includes screening for 9 conditions, such as Sickle cell disease, Cystic fibrosis, and Phenylketonuria, among others.
What are some of the conditions included in the NBS screening programme since 2014?
Sickle cell disease (SCD), Cystic fibrosis (CF), Congenital hypothyroidism (CHT), Phenylketonuria (PKU), and more.
Define Inherited metabolic diseases.
They are genetic diseases that affect metabolism, such as PKU, MCADD, MSUD, IVA, GA1, and HCU.
How many babies born in the UK have PKU or MCADD?
About 1 in 10,000 babies born in the UK have PKU or MCADD.
Describe Sever Combined Immunodeficiency (SCID).
It is a group of rare, inherited disorders causing major abnormalities of the immune system, usually due to the absence or malfunction of a necessary protein.
What happens without treatment for babies with inherited metabolic diseases?
Babies can become suddenly and seriously ill, with different symptoms depending on the specific condition, which can be life-threatening or cause severe developmental problems.
Describe the concept of screening for disease according to Wilson and Jungner.
Screening is the presumptive identification of unrecognized disease or defect through tests, examinations, or procedures that can be rapidly applied.
What are the criteria that need to be fulfilled for a condition to be suitable for screening, as per Wilson and Jungner?
The condition should be an important health problem, have an accepted treatment, facilities for diagnosis and treatment available, a recognizable early stage, a suitable test acceptable to the population, understood natural history, agreed policy on treatment, economically balanced cost, continuous case finding, and resources for follow-up.
How are inborn errors of metabolism typically treated?
They can be treated with a carefully managed diet and, in some cases, medication.
Define familial hypercholesterolaemia (FH) in terms of its genetic basis.
It is an inherited defect in cholesterol/lipoprotein metabolism.
What is the significance of MS-MS methods in the context of inborn errors of metabolism screening?
MS-MS methods, particularly tandem mass spectrometry, have contributed significantly to the technical advances in screening for these conditions.
How does early disease detection and treatment contribute to combating diseases, according to Wilson and Jungner?
Early detection and treatment aim to bring undetected cases to treatment while avoiding harm to those who do not need treatment, although the path to successful achievement is complex.
Describe the biochemical basis of conditions like PKU and MCADD.
The biochemical basis involves specific metabolic pathways that are affected in these conditions, leading to the accumulation of certain substances or the inability to break down others.
What is the role of the NHS Screening Programme in relation to inborn errors of metabolism?
The NHS Screening Programme plays a crucial role in identifying and referring babies suspected of having these conditions for clinical care.
How do inborn errors of metabolism fulfill the criteria for suitable screening conditions?
They fulfill the criteria by being important health problems with accepted treatments, available facilities, recognizable early stages, suitable tests, understood natural history, agreed treatment policies, balanced costs, continuous case finding, and resources for follow-up.
What is the quote regarding the rarity of individual inborn errors of metabolism but their overall significance?
“Each individual inborn error of metabolism is rare but the total incidence is significant.”
Describe the potential consequences if children with certain conditions are left undiosed and untreated.
Children may require hospitalization for extended periods, intensive care, and long-term institutional care, impacting both families and healthcare systems.
Define the criteria that need to be met for a condition to considered suitable for newborn screening.
The condition must be an important health problem, have an accepted treatment, facilities for diagnosis and treatment available, a recognizable early stage, a suitable test, acceptable to the population, understood natural history, agreed policy on treatment, economically balanced case finding, and a continuous screening process.
What is the Guthrie test and its significance?
The Guthrie test, also known as the ‘heel prick’ test, was established by Robert Guthrie in 1962. It was the original test for phenylketonuria (PKU) and used a bio-assay to test for phenylalanine, phenylpyruvate, and/or phenyllactate.
How many conditions are currently included in the NHS newborn blood spot screening programme?
There are 9 conditions included in the programme since 2014, including sickle cell disease, cystic fibrosis, congenital hypothyroidism, inherited metabolic diseases, phenylketonuria, medium-chain acyl-CoA dehydrogenase deficiency, maple syrup urine disease, isovaleric acidemia, and glutaric aciduria type 1.
Describe the effects of untreated thyroxine deficiency in congenital hypothyroidism.
Untreated thyroxine deficiency can lead to failure to thrive, delayed development, intellectual developmental disorders, infertility, and congenital iodine deficiency syndrome.
What are some causes of congenital hypothyroidism?
Causes include lack of dietary iodine, complete absence of the thyroid gland, abnormal development of the thyroid gland, and rare genetic defects affecting thyroxine biosynthesis.
Explain the process of thyroxine biosynthesis.
Thyroxine biosynthesis involves the absorption of iodine by the thyroid gland, which starts functioning around 20 weeks gestation. It can be affected by genetic causes such as mutations in the receptor for thyroid stimulating hormone, certain transcription factors, and mutations in proteins involved in thyroxine production like Na+/I- symporter, thyroglobulin, and thyroid peroxidase.
Describe the process of thyroxine biosynthesis in the thyroid gland.
Throxine is produced through the uptake of iodine via the Na+/I- symporter, iodination of tyrosine residues in thyroglobulin, coupling of iodinated tyrosines, endocytosis, proteolysis, and secretion into circulation via monocarboxylate transporter.
