X-linked Dominant Inheritance

Question 1

____ is inherited as an X - linked dominant trait and thus both males & females are usually affected.

Answer 1

Vitamin D - resistant rickets (or X - linked hypophosphataemia)

Question 2

T/F. In X-linked dominant traits, whereas in males the condition is uniformly severe, the female heterozygote is more variably affected because of X inactivation.

Answer 2

True.

Question 3

The pedigree for X-linked dominant traits resembles that of an ____ but the key difference is the lack of male - to - male transmission with an X - linked dominant trait.

Answer 3

autosomal dominant trait

Question 4

What other trait is inherited through X-linked dominant fashion?

Answer 4

Xg blood group

Question 4

This X-linked dominant trait is characterized by an early onset of a vesicular skin rash followed by irregular whorled pigmentation in a mosaic pattern, with affected regions representing those in w/c the normal chromosome has been inactivated.

Answer 4

incontinentia pigmenti (partial deletion of the NEMO gen)

Question 5

This X-linked dominant trait is characterized by atrophy & linear pigmentation of the skin, together with digital and oral anomalies, learning disability and striated bones.

Answer 5

focal dermal hypoplasia

Question 6

This X-linked dominant trait is characterized by developmental arrest at 6 – 18 months followed by regression, ‘ hand - washing ’ automatisms, subsequent seizures and then wheelchair dependency by the age of 10 years.

Answer 6

Rett syndrome (MECP2 gene mutations)

Question 7

This X-linked dominant trait is characterized by epilepsy with multiple uncalcified nodules on the walls of the lateral ventricle.

Answer 7

X-linked periventricular heterotopia (FLNA gene mutations)