carls14aren't retinal cells a type of somatic cell? Why not is the mutation not considered in the somatic cell of the child?+10
omertaAlthough this mutation would be considered somatic, I believe the question is just asking you to be specific as to which cells. If you answered "somatic cells of the child," that's quite broad and could apply to almost anything. +13
eacvThere is a Uworld qx that explain this in detail> ID: 863+3
arcanummI read the answer options too fast so got this wrong. It is a somatic cell type, but somatic in general implies a higher risk for developing other cancers. The hint here is that the physician stated he is unlikely to develop any other neoplasms, so it is a specific double hit mutation in the retina.+7
almondbreezewouldn't she have any possibility of developing osteosarcoma as well? :(+
almondbreezedid some reading and it seems like osteosarcoma only occurs in familial retinoblastoma with RB mutation+
briseBut how can a 5 year old get two mutations to get retinoblastoma? In 5 years?! Obviously doctor is probably wrong LOL+1
jaramaihaThe difference between familial and sporadic mutations dealing with Rb is that in this case he only had one hit so that only one eye is affected. In other words, if he would have been born with the familial type, he would present with Rb in both eyes and also be predisposed to osteosarcoma. In this instance he only has Rb in one eye having only a one hit mutation in his right eye. When the stem says this is the first mutation it's implying that he wasn't born with the familial type so to obtain a second mutation over the course of his lifetime would be rare. +
brise@jaramiaha I believe it still falls into a two hit mutation, but both were sporadic. But you are right about being unilateral. +
jaramaihaSorry I'm just getting back to this. Been on the grind and taking my exam Monday fingers crossed but I found the section I was thinking about when I first wrote this. In Pathoma chapter 3 page 27 (in the 2018 edition) located in the end of the section discussing tumor suppressor genes. It talks about the sporadic mutation in Rb(both hits being somatic) is characterized by unilateral retinoblastoma. While germline mutation results in familial retinoblastoma (2nd hit is somatic), characterized by retinoblastoma and osteosarcoma. +
abhishek021196 One-third of all retinoblastomas are hereditary : RB1 gene mutations are present in all of the body's cells, including reproductive/germ (sperm or eggs) cells - k/as germline mutation/gametic mutation : mutations in the cells from which egg or sperm cells develop. These patients thus have higher risk of developing cancers in other body parts as well and can also pass these mutations to their offspring. The other two-thirds of retinoblastomas are non-hereditary, which means that RB1 gene mutations are present only in retinal cells of that eye and do not occur in the germline - k/as somatic
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abhishek021196continued to my previous comment - These patients do not have risk of developing cancer in other body parts and as they do not occur in the germline, they cannot be passed on to offspring via the ovum or sperm. +
submitted by โjooceman739(33)
Retinoblastoma:
The physician said the boy is unlikely to develop any other neoplasms, so he doesn't have the inherited Rb mutation.
In this case, he has the sporadic retinoblastoma. Sporadic retinoblastoma requires two somatic mutations of Rb in the same retinal cell.
Just as a side note: Inherited retinoblastomas tend to be bilateral. Sporadic are unilateral.