Question 1

Which of the following genes is most directly associated with histone modification enzyme dysfunction leading to facial dysmorphisms and developmental delay?

Accepted Answer

KMT2A

Question 2

A patient presents with downslanted palpebral fissures, prominent beaked nose, and short stature. Which gene mutation is most likely responsible for these features?

Accepted Answer

CBP, EP300

Question 3

Which of the following best describes the function of the protein encoded by ANKRD11?

Accepted Answer

Regulates histone acetylation

Question 4

A child with hypertelorism, downturned palpebral fissures, and developmental delay is found to have a mutation in a gene encoding a histone modification enzyme. Which gene is most likely mutated?

Accepted Answer

KMT2A

Question 5

Which clinical feature is most commonly associated with mutations in chromatin remodeler genes such as ARID1A, SMARCA4, and SMARCE1?

Accepted Answer

Facial dysmorphisms (bushy eyebrows, wide mouth), aplasia/hypoplasia of the distal phalanx, and sparse scalp hair

Question 6

A mutation in KDM6A is most likely to disrupt which cellular process?

Accepted Answer

Histone methylation

Question 7

Which of the following equations best represents the relationship between gene expression ($$E$$), histone acetylation ($$A$$), and chromatin accessibility ($$C$$)?

Accepted Answer

$$E = A 	imes C$$

Question 8

A patient with amputed upper central incisors, short stature, and skeletal anomalies is most likely to have a mutation in which gene?

Accepted Answer

ANKRD11

Question 9

Which of the following is a real-world consequence of defective chromatin remodeling in neural development?

Accepted Answer

Microcephaly, seizures, and developmental delay

Question 10

If a histone modification enzyme is nonfunctional due to a genetic mutation, which of the following is the most likely effect on gene expression?

Accepted Answer

Gene expression will decrease due to condensed chromatin

Question 11

Which gene is most likely mutated in a patient with facial asymmetry, cup-shaped ears, coloboma, and heart defects?

Accepted Answer

SMARCA2

Question 12

A mutation in which gene would most likely result in both facial dysmorphisms and growth deficiency due to altered third olfener eyelid anomalies?

Accepted Answer

KMT2D

Question 13

Which of the following best explains why mutations in chromatin remodeler genes can lead to developmental delay?

Accepted Answer

Chromatin remodelers regulate the accessibility of DNA for transcription, and mutations can reduce gene expression necessary for development.

Question 14

A patient with hypertelorism, joint contractures, and cryptorchidism is most likely to have a mutation in which gene?

Accepted Answer

KAT6B

Question 15

Which of the following is the most plausible mechanism by which histone modification enzymes influence phenotype?

Accepted Answer

By altering the acetylation and methylation status of histones, they change chromatin structure and regulate gene expression.

Question 16

A patient with facial dysmorphisms, hypotonia, and sparse scalp hair is most likely to have a mutation in which group of genes?

Accepted Answer

ARID1A, ARID1B, SMARCA4, SMARCB1, SMARCE1

Question 17

Which equation best models the effect of chromatin remodeling ($$R) on $$transcriptional activity ($$T) in a $$cell?

Accepted Answer

$$T = k 	imes R$$

Question 18

A patient with facial dysmorphisms, microcephaly, seizures, and developmental delay is most likely to have a mutation in which gene?

Accepted Answer

SMARCA2

Question 19

Which of the following is NOT a clinical feature associated with mutations in histone modification enzymes?

Accepted Answer

Sparse scalp hair

Question 20

A mutation in which gene would most likely result in both facial dysmorphisms and joint contractures due to altered histone modification?

Accepted Answer

KAT6B

Disorders of Transcriptional Regulation: Genetic Causes and Clinical Features

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