GENETICS - Ocular Conditions and HLA types

Question 1

HLA Associations
1. Birdshot choroidoretinitis
2. Presumed Ocular histoplasmosis syndrome / MS
3. Sarcoidosis/Intermediate uveitis
4. Idiopathic ant uveitis, psoriatic, ank spond, Reiter’s, IBD
5. Retinal vasculitis
6. Behcet’s disease
7. Juvenile RA, VKH syndrome, sympathetic ophthalmia

Answer 1

1. Birdshot - HLA-A29
2. POHS - B7, DR2. MS - B7, DR2, DR15
3. Sarcoidosis / IU - HLA-B8
4. Idopathic AU, psoriatic, AS, Reiter’s, IBD - HLAB27
5. Retinal vasculitis - B44
6. Behcet’s - B51
7. JRA, VKH, SO - DR4

Question 2

What chromosome codes HLA antigen?

Answer 2

Chromosome 6

Question 3

HLA Class I Antigens vs
HLA Class II Antigens

Answer 3

Class I : all nucleated cells, allows CD8+ cytotoxic T cells to recognise and eliminate virus infected cells

Class II: macrophages, dendritic cells, B cells, endothelial cells, allows initiation of immune response by interaction with T-helper CD4+ cells

Question 4

What are the mutations associated with these glaucoma conditions?

1. Pseudoexfoliation
2. Axenfeld-Reiger syndrome
3. Juvenile onset glaucoma
4. Congenital glaucoma
5. Normal tension glaucoma

Answer 4

1. LOXL-1
2. FOXC1 or PITX2
3. GLC1A (MYOC)
4. CYP1B1
5. OPT

Question 5

Where is the retinoblastoma gene found?

Answer 5

Rb gene on 13q

Question 6

What gene is the cause of aniridia? Where is the gene located?

Answer 6

PAX-6
Chromosome 11 (Autosomal dominant)

Question 7

What type of inheritance does retinitis pigmentosa have? What genes are the cause for which type?

Answer 7

1. Autosomal dominant - RHO gene on chromosome 3.
2. X-linked - RP2 and RPGR

Question 8

What gene is linked to Startgart’s disease?

Answer 8

ABCA-4 transporter

Question 9

What conditions are implicated with PAX-6 mutation (5)

Answer 9

1. Aniridia
2. Anophthalmia
3. Axenfeld-Reiger syndrome
4. Peter’s anomaly
5. Congenital glaucoma
6. Anterior segment dysgenesis