GENETIC DISORDERS

Question 1

One dominant allele is enough to produce phenotype (heterozygous); diseases with mutations in key structural proteins/receptors are usually inherited in this manner;

Answer 1

Autosomal dominant

Question 2

Two recessive alleles produce phenotype; enzyme deficiencies are usually inherited in this manner:

Answer 2

Autosomal recessive

Question 3

In this pattern of inheritance, males are usually affected due to hemizygosity of the allele, but females may express phenotype due to random activation of one X chromosome;

Answer 3

X-linked recessive disorders

Question 4

In this pattern of inheritance, females in general are more affected than males (in any scenario), because one allele in a female is enough to manifest the trait;

Answer 4

X-linked dominant disorders

Question 5

Huntington disease,

Answer 5

Autosomal dominant

Question 6

Cystic fibrosis

Answer 6

Autosomal recessive

Question 7

Duchenne muscular dystrophy

Answer 7

X-linked recessive disorders

Question 8

Alport syndrome

Answer 8

X-linked dominant disorders

Question 9

Lesch-Nyhan syndrome

Answer 9

X-linked recessive disorders

Question 10

Vitamin D-resistant rickets

Answer 10

X-linked dominant disorders

Question 11

Hemophilia A and B

Answer 11

X-linked recessive disorders

Question 12

Ehler-Danlos Syndrome (some types)

Answer 12

Autosomal dominant

Question 13

Neurofibromatosis

Answer 13

Autosomal dominant

Question 14

Myotonic dystrophy

Answer 14

Autosomal dominant

Question 15

Phenylketonuria

Answer 15

Autosomal recessive

Question 16

enzyme deficiencies are usually inherited in this manner:

Answer 16

Autosomal recessive

Question 17

Chronic granulomatous disease

Answer 17

X-linked recessive disorders

Question 18

Tuberous sclerosis complex

Answer 18

Autosomal dominant

Question 19

Autosomal dominant

Answer 19

X-linked recessive disorders

Question 20

Galactosemia, Homocystinuria, Lysosomal storage diseases, α-1-antitrypsin deficiency, Wilson disease, Hemochromatosis, Glycogen storage diseases, Sickle cell anemia, Thalassemias, Congenital adrenal hyperplasia, Ehler-Danlos Syndrome (some types), Alkaptonuria

Answer 20

Autosomal recessive

Question 21

Neurogenic muscular atrophies, Freidrich ataxia, Spinal muscular atrophy

Answer 21

Autosomal recessive

Question 22

Agammaglobulinemia, WiskottAldrich syndrome, Diabetes insipidus, Lesch-Nyhan syndrome, Fragile X syndrome

Answer 22

X-linked recessive disorders

Question 23

Marfan syndrome

Answer 23

Autosomal dominant

Question 24

ADPKD

Answer 24

Autosomal dominant

Question 25

familial polyposis coli

Answer 25

Autosomal dominant

Question 26

Osteogenesis imperfecta

Answer 26

Autosomal dominant

Question 27

Marfan syndrome

Answer 27

Autosomal dominant

Question 28

Achondroplasia

Answer 28

Autosomal dominant

Question 29

Familial hypercholesterolemia, Acute intermittent porphyria

Answer 29

Autosomal dominant

Question 30

Most common of the chromosomal disorders; leading cause of MR

Answer 30

Trisomy 21 (Down syndrome)

Question 31

most common cause of trisomy 21

Answer 31

nondisjunction of Ch21 during meiosis

Question 32

diagnostic clinical features: flat facial profile, oblique palpebral fissures, and epicanthal folds

Answer 32

Trisomy 21 (Down syndrome)

Question 33

Prominent occiput, mental retardation, micrognathia, low-set ears, short neck, overlapping fingers, cardiac defects, renal malformations, limited hip abduction, and rocker-bottom feet are features of this syndrome

Answer 33

trisomy 18 (Edward syndrome)

Question 34

Microcephaly and mental retardation, microphathalmia, cleft lip and palate, polydactyly, cardiac defects, umbilical hernias, renal defects, and rocker-bottom feet are features of this syndrome

Note: Italicized feature

Answer 34

trisomy 13 (Patau syndrome)

Question 35

features that would differentiate Patau syndrome from Edward syndrome

Answer 35

cleft lip palate and umbilical hernias

Question 36

Syndrome consisting of cardiac anomalies, abnormal facies, thymic hypoplasia, cleft palate, hypocalcemia,

Answer 36

DiGeorge syndrome

Question 37

DiGeorge syndrome is due to

Answer 37

due to deletion in the long arm of Chromosome 22 (part of Ch22q11.2 deletion syndrome, together with velocardiofacial syndrome)

Question 38

also known as 22q11.2 deletion syndrome

Answer 38

DiGeorge syndrome

Question 39

is a genetic condition characterized by abnormal pharyngeal arch development that results in defective development of the parathyroid glands, thymus, and conotruncal region of the heart.

Answer 39

velocardiofacial syndrome

Question 40

Condition characterized by ≥ 2 X chromosomes and ≥ 1 Y chromosomes

Answer 40

Klinefelter syndrome

Question 41

most common karyotype is 47XXY

Answer 41

Klinefelter syndrome

Question 42

Complete or partial monosomy of X chromosome; female hypogonadism in phenotypic females;

Answer 42

Turner syndrome

Question 43

important cause of reduced spermatogenesis and male infertility;

Answer 43

Klinefelter syndrome

Question 44

Most common abnormality is lack of entire X chromosome (45XO);

Answer 44

Turner syndrome

Question 45

single most important cause of primary amenorrhea;

Answer 45

Turner syndrome

Question 46

Type of hermaphrodism characterized by presence of both ovarian and testicular tissue

Answer 46

True hermaphrodism

Question 47

Type of hermaphrodism characterized by disagreement between phenotypic and gonadal sex;

Answer 47

Pseudohermaphrod ism

Question 48

syndromes with Pseudohermaphrodism

Answer 48

MRKH syndrome and androgenital syndromes

Question 49

clinical features include: ovarian streaks, absence of secondary sex characteristics, short stature, cystic hygromas of head neck, preductal CoA, etc.

Answer 49

Turner syndrome

Question 50

Most common cause of MR following Trisomy 21;

Answer 50

Fragile X syndrome

Question 51

Fragile X-syndrome

most distinctive feature is

Answer 51

macroorchidism

Question 52

Fragile X-syndrome

due to

Answer 52

CGG expansion in FMR1 gene in X-chromosome;

Question 53

Autosomal dominant neurodegenerative disorder;

Answer 53

Huntington disease

Question 54

Huntington disease

due to

Answer 54

CAG expansion on HTT gene on Ch4

Question 55

CAG expansion on HTT gene on Ch4; relentlessly progressive and uniformly fatal

Answer 55

huntington disease

Question 56

Deletion in paternally derived Chromosome 15;

Answer 56

Prader-Willi syndrome

Question 57

clinical features include: mental retardation, hypotonia, profound hyperphagia, obesity, small hands and feet, and hypogonadism

Answer 57

Prader-Willi syndrome

Question 58

Deletion in maternally derived Chromosome 15;

Answer 58

Angelman syndrome

Question 59

clinical features include: mental retardation, ataxic gait, seizure, and inappropriate laughter “happy puppet”

Answer 59

Angelman syndrome