Treacher collins syndrome

Question 1

what causes Treacher collins syndrome ?

Answer 1

when NCC do not migrate to the pharyngeal arches to form cranifacial structures

Question 2

what pharyngeal arches are affected by TCS?

Answer 2

1st and 2nd

Question 3

Is TCS genetically and phenotypically heterogenous or homogenous?

Answer 3

heterogenous

Question 4

what gene is the majority of TCS mutations in?

Answer 4

TCOF1

Question 5

what genes are the minority of TCS mutations in?

Answer 5

POLR1D and POLR1C

Question 6

what protein does TCOF1 encode?

Answer 6

treacle protein

Question 7

what proteins do POLR1D and POLR1C encode?

Answer 7

rna pol 1 and 111

Question 8

what is rna polymerase important in?

Answer 8

rna synthesis

Question 9

what does TCS cause?

Answer 9

aplasia of facial bones- underdeveloped facial bones

Question 10

name some features of TCS

Answer 10

-middle ear deformaties
-orbital deformaties
-zygomatic and mandibular deformaties
-clefts
-small jaw and chin

Question 11

what can also be seen in 50% of TCS patients?

Answer 11

hearing loss

Question 12

what is a life threatening problem that can occur in TCS newborns?

Answer 12

respiratory problems due to airway narrowing

Question 13

what is the treatment of TCS?

Answer 13

-early intervention of respiratory, hearing speech. etc
-facial reconstruction
-hearing aids or middle ear surgery

Question 14

what type of inheritance is the TCOF1 mutation?

Answer 14

autosomal dominance

Question 15

what does autosomal dominance mean?

Answer 15

non-sex chromosome
- only need single copy of mutated gene from parent

Question 16

what type of inheritance is POLR1D and POLR1C?

Answer 16

autosomal dominant and autosomal recessive

Question 17

what does autosomal recessive mean?

Answer 17

non sex chromosome
-requires a copy of mutated gene from both parents

Question 18

what does it mean when some mutations occur spontaneously?

Answer 18

they are not inherited from the parents

Question 19

what are the majority of mutations seen in TCOF1?

Answer 19

deletion mutations

Question 20

what does the deletion mutation in TCOF1 result in?

Answer 20

turnacated treacle protein- meaning it is small and non functioning

Question 21

where is treacle found to be active?

Answer 21

in embryonic developmental tissues than become bone and other tissues of the face

Question 22

what does the treacle protein do?

Answer 22

ribosomal processing and making of ribosomes

Question 23

what happens when TCOF1 is depleted in mice?

Answer 23

causes depletion of NCC cells through cell death- reduced no of NCC cells that migrate to CF complex