Genetic Hormonal Deficiencies- 28 Flashcards
What ways do mutations in coding DNA regions affect proteins
Point mutations- Silent, Nonsense, Missense
What other factors can cause diseases
Environmental and genetic factors
What is a congenital disorder
A disorder that is present at birth.
What are symptoms of congenital hypothyroidism.
Symptoms in infants can be mild, such as low body temperature, poor muscle tone, excessive sleeping
What can happen if congenital hypothyroidism is left untreated
It can lead to reduced growth and intellectual dysfunction which is permanent.
What is the causes of congenital hypothyroidism
In certain countries, most common cause is maternal iodine deficiencies
Can also be an underdeveloped thyroid gland which is caused by mutations in: Thyroglobulin gene or gene encoding TSH (thyroid stimulating hormone)
What is the treatment for congenital hypothyroidism.
Thyroxine (T4) is given orally for treatment daily.
How are newborns screened for congenital hypothyroidism.
Involves a “blood spot” procedure where blood is taken and measured for levels of T4 and TSH
What causes Allan-Herndon Dudley Syndrome
A loss of function mutation in the MCT8 gene (x-linked)
What are the symptoms of Allan-Herndon Dudley Syndrome
Sever cognitive deficiency
Infantile Hypotonia
Progressive spastic Quadripalgeia
Most affected males never walk or sit independantly
Most never speak
What are the levels of thyroid hormone in Allan-Herndon Dudley Syndrome
T3 increased
T4 decreased
TSH normal/slightly increased
What is the treatment for Allan-Herndon Dudley Syndrome
Diiodothyropropionic Acid (DITPA)
What causes Isolated Hormone Deficiency
Most are idiopathic although mutations have been identified in,
GH1 gene encoding growth hormone
GHRHR
What is the treatment for Isolated Growth Hormone Deficiency
If treated early children can reach full height
Treatment involves daily injections of GH
What are the two parts of the adrenal gland
The cortex and the medulla
What does the adrenal cortex secrete
Steroid hormones- Alsosterone, cortisol, adrenal androgens
What happens during the short term stress response
Glycogen converted to glucose
Increase blood glucose, blood pressure, breathing rate, metabolic rate
What happens in the long term stress response
Sodium ions and water by kidneys
Increase blood volume and blood pressure
Conversion of proteins and fats to glucose
Immune system supressed
What causes congenital adrenal hyperplasia
An autosomal recessive disorder caused by a deficiency of enzymes used to make cortisol and aldosetrone
A mutation in the 21-hydroxylase gene
What does congenital adrenal hyperplasia cause an increase in
Produces more androgens causing innapropriate or early development of male characteristics
What are the symptoms of classical salt wasting 21-hydroxylase deficiency
Ambiguous female genitalia
Reduced aldosterone and cortisol secretion
Increased testosterone
What are the symptoms of classical simple virilising 21-hydroxylase deficiency
Ambiguous female genetilia
Normal Aldosterone
Reduced Cortisol
Increased Tesosterone
WHat are the symptoms of 21-hydroxylase deficiency
Non-classical
Virillised Female Genetilia
Normal aldosterone and cortisol
Increased Testosterone
What are the symptoms of Congenital Adrenal Hyoerplasia
Abnormal genitalia in girls (hence quicker diagnosis than males)
- clitoris may be enlarged and the urethra and vagina may merge
* Baby girls do not usually become seriously ill through complications (because of early diagnosis)
* Salt-wasting
* Hypotension
* Hyponatremia
* Hyperkalaemia
* Hypoglycaemia
* Outward signs of salt-wasting form include dehydration, vomiting, weight loss, extreme tiredness
What is the treatment options for Congenital Adrenal Hyperplasia
Corticosteroids (oral hydrocortisone)- regulate blood glucose
Mineralcorticoids- oral fludrocortisone
Surgery to correct abnormal female genetelia- clitoroplasty
Mother can be given dexamethasone before birth.
