genetic hormonal deficiencies Flashcards
(29 cards)
what are diseases caused by?
genetic and/or environmental factors
what are genetic factors?
gene mutations
how many chromosomes does a single human copy have?
23
22 autosomes and 1 sex chromosome (X or Y)
where is the diploid human genome present
in somatic cells
how does mutations in non-coding DNA affect proteins?
May have no effect on protein expression
May affect protein expression
what are autosomal dominant diseases?
if a mutation in one allele causes the disease
what are autosomal recessive diseases?
require both alleles to carry mutation
what is a congenital disorder?
present at birth
what is congenital hypothyroidism?
- present from birth
- symptoms in infants may be mild or not recognised as thyroid problem: jaundice, low body temp, poor muscle tone, excessive sleeping
what can congenital hypothyroidism lead to if untreated?
reduced growth and intellectual dysfunction
what genetic mutations could cause congenital hypothyroidism?
- thyroglobulin gene
- the gene encoding the sodium iodide symporter
- the gene encoding TSH
- the gene encoding TSHR
what is treatment of congenital hypothyroidism?
- thyroxine daily treatment
- if treated correctly, growth and development is normal
what screenings can be done for cogenital hypothyroidism?
blood spot procedure (also known as heel prick) where blood is taken and measure for levels of T4 and TSH
what is allan-herdon-dudley syndrome?
very rare disorder caused by loss of function mutation in the MCT8 gene
symptoms: severe cognitive deficiency
- most affected males never walk
- most never speak
what is a therapeutic strategy being tested for AHDS
Development of membrane permeable thyroid hormone analogues
- diiodothyropropionic acid
- tested in 4 children (some improvements but not neurological improvements)
what is isolated growth hormone deficiency?
- autosomal-recessive condition caused by a shortage or absence of GH
what mutations have been identified in isolated growth hormone deficiency?
- GH1 gene encoding GH
- GHRHR gene encoding growth hormone releasing hormone receptor
what is noted from a few months of age for isolated growth hormone deficiency?
impaired length growth
defects in bone maturation
delayed puberty
what is treatment of isolated growth hormone deficiency?
daily injections of GH
what does the medulla in the adrenal glands secrete?
amine hormones eg. adr and NA
what does cortex in adrenal glands secrete,
steroid hormones eg.
Mineralocorticoids - aldosterone
Glucocorticoids- cortisol
adrenal androgens
when do adrenal androgens become detectable?
from about 6 years in age (especially dehydroepiandrosterone)
what does DHEAS convert to in peripheral tissue?
more potent androgens testosterone and dihydrotestosterone or to estrodiol
in females what % of the adrenal gland contributes to active androgens
50
