Term
| How do we know SRY is transcription factor for sexual differentiation |
|
Definition
SRY present in XX males
Mutations in SRY sequence in XY females
SRY expressed only in male gonadal ridge
Transgenic XX mice with portion of Y chromosome containing SRY -> males |
|
|
Term
|
Definition
Both X's active in early zygote.
Blocking factor(autosomal) blocks xist binding.
Xist inactivates x chromosome.
X-inactivation is not uniform: some genes escape. |
|
|
Term
| Tracking X-inactivation using CAG repeat in autosome region |
|
Definition
Hpall won't cut methylated DNA.
2 peaks to 2 peaks. normal
2 peaks(undigested) to 1 peak(digested) carrier |
|
|
Term
| Craniofrontonasal syndrome(CFNS) |
|
Definition
Unusual X-linked dominant condition.
Heterzygous is most severily affected.
Proteins produced don't match -> imprecise boundfry formation. |
|
|
Term
| Androgen insensitivty / Testicular feminisation |
|
Definition
X-linked
Mutations in androgen receptor.
XY phenotypically females although inferile.
MIF will still block internal female genitalia |
|
|
Term
|
Definition
Both X's active in early zygote.
XIST: no open reading frame, acts as mRNA
BF(autosomal) blocks xist binding. Only enough for 1 chromosome.
XIST RNA coasts Xi and turns into heterochromating. Methylation, histone deacetylation.
X-inactivation is not uniform, some genes escape. |
|
|
Term
|
Definition
CAG repeat in autosome region of X chromosome.
Hpall won't cut methylated(inactive) DNA
2 peaks to 2 peaks = normal. 2 peaks undigested to 1 peak digested = carrier |
|
|
Term
| Craniofrontonasal Syndrome CFNS |
|
Definition
X-linked Dominant
Females more severely affected
Loss of function mutations in EFNB1.
Heterozygotes are affected. (proteins dont match.
Hypertelorism, coronal synostosis, longitudinal nail split |
|
|
Term
Alpha Thalassaemia with Mental Retardation
ATRX |
|
Definition
X-linked
mutation in SWI2/SNF
Helicase determines local structure of chromatin. (regulates gene expression) |
|
|
Term
| Epigenetics General facts |
|
Definition
Silence certain genes. Define cell types
Problems in imprinting involved in cancer
Epigenetic changes occur during development. May be affected by environment.
May affect penetrance |
|
|
Term
| Changes of state of methylation in development |
|
Definition
Primordial germ cells = low methylation
Sperm/Egg = High methylation
Fertilized = Low methylation
Adulthood = Increases especially somatic |
|
|
Term
| Autosomal dominant glomus tumors |
|
Definition
Manifest when mutation is inherited from father.
Maternal allele is imprinted. |
|
|
Term
| Beckwith-Weidemann syndrome BWS |
|
Definition
manifests when mutation inherited from mother
Paternal allele is imprinted |
|
|
Term
PWS(prader willi syndrome)
and
AS(angelmens syndrome) |
|
Definition
Usually both are deleted together.
Only see one effect though due to imprinting.
PWS = Paternal inherited
Angelmann = Maternal Inherited
Deletion visble w/ standard karyotype
Southern blot to detect methylation of SNRPN.
PWS - Uniparental disomy
AS - point mutation UBE3A |
|
|
Term
| Albright Hereditary osteodystrophy(AHO) |
|
Definition
Short Stature, obesity, brachydactly
Heterozygous loss of function mutation.
(Autosomal dominant) Haploinsufficiency |
|
|
Term
|
Definition
PPHP - AD, AHO without hormone resistant.
Paternal Inherited
PHP1A- AD, AHO+ multiple hormone
resistance. Maternally Inherited.
PHP1B - AD, Renal PTH resistance no AHO
Imprinting error in renal tubules. |
|
|
