nbme2 ,Q6 - mdkhayat

[ArchivalUser]

n the pedigree illustrating a syndrome associated with various neoplasms, individuals whose symbols are solid black have manifestations of the syndrome. The neoplasm & their ages at onset in the affected individuals are as follows

Pedigree number type of neoplasm age at onset (years)
1-2 carcinoma of breast (right) 28
Carcinoma of breast (left) 36
II-2 carcinoma of breast 51
II-3 myxofibrosarcoma 48
III-2 medulloblastoma 5
III-4 rhabdomyosarcoma 8

This pedigree illustrates
a) Anticipation
b) Genetic heterogeneity
c) Incomplete penetrance
d) Multifactorial inheritance
e) Variable expressivity

[ArchivalUser]

BBB

[ArchivalUser]

yes, may be locus or allelic heterogeniety ,ya?

[ArchivalUser]

i found a Q

A man and a woman, each of whom has autosomal recessive congenital deafness, have four biological children, each of whom has normal hearing. Which of the following terms best matches the clinical vignette.
A. Incomplete penetrance
B. Allelic heterogeneity
C. Anticipation
D. Variable expressivity
E. Locus heterogeneity

[ArchivalUser]

b,

[ArchivalUser]

its E. Deafness is characterized by locus heterogeneity in which mutations in distinct genes can result in the identical clinical phenotype. Because the genetic pathway controlling hearing is complex and is dependent on multiple gene interactions, it is likely that the two parents have mutations is different genes. As a consequence, their progeny can inherit a functional copy of each required gene in the hearing pathway from the combination of functional genes from each of the two parents.

[ArchivalUser]

http://www.usmleforum.com/showthread.php?tid=780740

[ArchivalUser]

yes ,thanks .I am weak in these type of Qs and also bacterial genetic .
please if you find some Qs send me.
thanks.

[ArchivalUser]

yeah will do