X-linked Disorders

Question 1

X-dominant can come from

Answer 1

Either parent

Question 2

Menkes related syndrome

Answer 2

Occipital horn syndrome

Question 3

Menkes symptoms

Answer 3

Sparse,kinky hair 
Failure to thrive 
Deterioration of nervous system
Hypotonia 
Seizures
Interllectual disability

Question 4

Occipital horn syndrome

Answer 4

X-linked cutis laxa…manifests in early to middle childhood
Wedge-shaped clacium deposits on occipital bone
Coarse hari
Loose skin and joints

Question 5

Genetic basis of Menkes/occipital horn

Answer 5

Mutation of ATP7A on X chromosome…protein from gene important for maintaining copper levels…APT7A normally in the golgi where it supplies copper to newly synthesized proteins critical in function for hair, bone, skin, and nervous system…if cellular copper elevates, ATP&A move to plasma membrane to assist in eliminating copper from cell

Question 6

Lesch0Nyhan syndrome quick pathology

Answer 6

Overproduction of uric acid

Question 7

Lesch-Nyhand syndrome characterization

Answer 7

Dystonia
Chorea 
Ballismus 
Gouty Arthritis 
Pontentailly uric-acid related kidney and bladder stones

Question 8

Behavior issue of Lesch-Nyhand

Answer 8

Slef-injury of biting and head banging

Question 9

Dystonia, ballismus, and gouty arthritis

Answer 9

Dystonia - involuntary tensing of muscles
Ballismus - flailiing of the limbs
Gouty arthritis - buildup of uric acid in the joints

Question 10

Genetic basis of Lesch-Nyhand

Answer 10

HPRT1 gene…normally produces hypoxanthine phosphoribosyltransferase 1…plays role in recycling purines….in mutation, purines can be broken down but not recycled, meaning uric acid accumulation…also leads ot low levels of dopamine in the brain

Question 11

Wiscott-Aldrich characterization

Answer 11

Reduced ability to make WBC
Microthrombocytopenia
Ready bruising
Episodes of prolonged bleeding due to impaired clot formation
Increased risk of immune/inflammatory disorders
Eczema

Question 12

Microthrombocytopenia

Answer 12

Decrease in number and size of platelets

Question 13

Genetic basis of microthrombocytopenia

Answer 13

Mutation in WS gene…protein from WASP relays signals from surface of blood cells to actin cytoskeleton…WASP activates blood cells when needed and results in cells moving and attaching to tissues…important for platelet clotting…in white blood cells, allows interaction with foreign bodies…mutations in WAS lead to lack of functional WASP, decreasing ability of cells to respond and impairing platelet defvelpooment

Question 14

X-linked, infantile spinal muscular atrophy chracteristics

Answer 14

Loss of motor neurons 
Hypotonia 
Difficulty breathing 
Areflexia 
Contractures (joint deformities)
Potentially broken bones at birth

Question 15

Areflexia

Answer 15

Absence of normal reflexes

Question 16

Genetic pases of X-lined, infantile spinal muscular atrophy

Answer 16

UBA1 gene codes for ubiquitin-acitivating enzyme E1 important in protein degradation…mutations lead to reduced levels or absence of this enzyme and a buildup of proteins…excess proteins lead to cell death, particularly motor neuron cell death