Sex - Linked

Question 1

X-linked Dominant Disorders

Answer 1

Hypophosphatemic Rickets, Fragile X Syndrome, Charcot Marie Tooth disease, Incontinentia pigmenti rett syndrome, Orofacicodigital syndrome, foracl dermal hypoplasia

Question 2

Hypophosphatemic Rickets

Answer 2

X-linked Dominant PHEX, regulates fibroblast GF inhibits the kidneys ability to reabsorb phosphate into blood

Question 3

Hypophosphatemia, short stature, bone deformity

Answer 3

Hypophosphatemic Rickets

X-linked Dominant

Mutation: PHEX, regulates fibroblast GF inhibits the kidneys ability to reabsorb phosphate into blood

Question 4

Fragile X Syndrome

Answer 4

X-linked dominant Trinucleotide repeat disorder CGG (in 5’UTR region) Anticipation, Maternal transmission

Clinical: ID, dysmorphic features (large ears, long face, macroorchidism), Autism, Social anxiety, hand flapping/biting, aggression

Mutation: FMR1 (protein essential for normal cognitive devo and female repo. function increase trinucleotide repeat number methylate gene–> LOF

Question 5

ID, dysmorphic features (large ears, long face, macroorchidism), Autism, Social anxiety, hand flapping/biting, aggression

Answer 5

Fragile X Syndrome X-linked dominant Trinucleotide repeat disorder CGG (in 5’UTR region) Mutation: FMR1 (protein essential for normal cognitive devo and female repo. function increase trinucleotide repeat number methylate gene–> LOF

Question 6

Rett Syndrome

Answer 6

X-linked Dominant

Clinical: Loss of normal movement and coordination, loss of communication skills, failure to thrive, Seizures, abnormal hand movements

Mutation: MECP2 (methyl CpG binding protein) essential for the normal function of nerve cells

Question 7

Loss of normal movement and coordination, loss of communication skills, failure to thrive, Seizures, abnormal hand movements

Answer 7

Rett Syndrome

X-linked Dominant

Mutation: MECP2 (methyl CpG binding protein) essential for the normal function of nerve cells

Question 8

X-linked Recessive Disorders

Answer 8

Lesch-Nyhan Syndrome Dystrophinopathies Hunter’s Disease Menaces Disease Glucose 6 phosphate dehydrogenase deficiency Hemophilia A and B Wiscott Aldrich Syndrome Colorblindness

Question 9

Lesch-Nyhan Syndrome

Answer 9

X-linked recessive

Clinical: Neurological and behavioral abnormalities, overproduction of uric acid, self injury

Mutation: HPRT1 recycling of purines

Question 10

Neurological and behavioral abnormalities, overproduction of uric acid, self injury

Answer 10

Lesch-Nyhan Syndrome

X-linked recessive

Mutation: HPRT1 recycling of purines

Question 11

Dystrophinopathies

Answer 11

X-linked recessive s

pectrum of muscle disease from mild to severe: Duchenne Muscular Dystrophy (most severe) Becker Muscular Dystrophy DMD-associated dilated cardiomyopathy

mutation: DMD (dystrophin) Xp21-21.1

Question 12

Duchenne Muscular Dystrophy

Answer 12

X-linked recessive

Clinical: Progressive muscular weakness (proximal to distal), calf hypertrophy, dilated cardiomyopathy, High CK levels, onset before age 5, wheelchair before age 13, death in 30s No dystrophin

Mutation: DMD

Question 13

15 yo, wheelchair bound since age 13, muscle weakness, calf hypertrophy, dilated cardiomyopathy, CK levels x10

Answer 13

Duchenne Muscular Dystrophy

X-linked recessive

Question 14

Becker Muscular Dystrophy

Answer 14

X-linked recessive

Clinical: Progressive muscular weakness (proximal to distal), dilated cardiomyopathy, CK levels 5x, onset later than duchenne muscular dystrophy, wheelchair bound after 16yo, death in 40s abnormal quantity or quality of Dystrophin

Mutation: DMD

Question 15

20 yo, wheelchair bound since age 16, muscle weakness that developed over time, dilated cardiomyopathy, CK levels 5x

Answer 15

Becker Muscular Dystrophy

X-linked recessive

Question 16

DMD-associated DCM

Answer 16

X-linked recessive

Clinical: dilated cardiomyopathy presenting between 20-40 yo, early death, no skeletal muscle involved no dystrophin in myocardium

Mutation: DMD

Question 17

Died around 55 after presenting with dilated cardiomyopathy at age 30

Answer 17

DMD-associated Dilated Cardiomyopathy

Question 18

Hemophilia A

Answer 18

X-linked recessive

Clinical: Spontaneous bleeds into joints, muscles or intracranial. excessive bruising, prolonged bleeding after injury, delayed wound healing

Mutation: F8 deficiency of factor VIII, chr. Xq28

Question 19

Spontaneous bleeds into joints, muscles or intracranial. excessive bruising, prolonged bleeding after injury, delayed wound healing

Answer 19

Hemophilia A

X-linked recessive

Mutation: F8 deficiency of factor VIII, chr. Xq28