Gene therapy involves introducing a biologically active gene into a cell to achieve a therapeutic benefit and can be done in two ways. Vectors like retroviruses and adeno-associated viruses are used to deliver the therapeutic gene to target cells like stem cells and progenitor cells. RNA interference is a type of gene modulation being used to treat genetic diseases like Huntington's disease by decreasing production of faulty proteins. Exon skipping induced by antisense oligonucleotides is also being researched for Duchenne muscular dystrophy treatment and could lead to a functional dystrophin protein. Genome editing techniques like CRISPR/Cas9 allow permanent changes to DNA and are being explored for curing diseases like HIV.

1. TREATMENT OF GENETIC DISEASES
Aadhav Ardha Narish Srinivasan
Raja Mohamed

2. GENE THERAPY
What is gene therapy?
Gene therapy is the introduction of a
biologically active gene into a cell to
achieve a therapeutic benefit

3. IT CAN BE DONE IN 2 WAYS

4. IMPORTANT COMPONENTS
Vectors
• Retroviruses
• Adenoassociated viruses (AAVs)
• Adenoviruses
Target Cells
• Stem cells
• Progenitor cells

5. CASE
STUDY• 18 year old male was reported
• Medical history revealed that he is a known case of XYZ since he was
One and a half year old, for which he has been undergoing Blood
transfusion
• Patient had undergone Splenectomy 2 years back.
• On general examination
i. Under-built & Under-nourished with a short stature
ii. Evident Icterus (jaundice)
iii. Yellow tinged fingernails
iv. Skin was grey in colour
• Head and Neck examination revealed classical “Chipmunk facies”
• The patient was then subjected for haematological examination &
results were positive for Hemolytic Anemia
What could XYZ be?

6. CASE
STUDY
Short stature Jaundice eyes Chipmunk Facies

7. β-THALASSEMIA
Mutations in the Hemoglobin Beta (HBB) gene

8. TREATMENT OF β-THALASSEMIA

9. HAEMOPHILIA B
Mutations in F9 Gene, leading to a deficiency or dysfunction of clotting factor IX

10. which organ do we infuse
the vector in Hemophilia B?
Q

12. TREATMENT OF HAEMOPHILIA B

13. What's the difference
between Hemophilia A & B?
Q

15. SEVERE X-LINKED COMBINED IMMUNODEFICIENCY
Mutations in the X-linked gene (IL2RG) encoding the γc-cytokine receptor subunit
of several interleukin receptors
Children affected with SCID in their protective bubble

16. TREATMENT OF SCID

17. METACHROMATIC LEUKODYSTROPHY
Mutations in the ARSA Gene which encodes Arylsulfatase A
Lysosomal enzyme that degrades Sulfatides, Which are neurotoxic to the central
and peripheral nervous system.
• Loss of motor function
• Loss of cognitive ability
• death
Child suffering from MLD

18. TREATMENT OF MLD

19. MODULATION OF GENE EXPRESSION
Modulation of
gene expression
RNA
interference
Induction of
Exon Skipping
Gene Editing

20. CASE
STUDY
• 42 year old male
• Marked postural instability.
• Dysarthria, clumsiness in upper limbs and memory complaints
along difficulties to perform daily activities
• General physical examination was normal.
• Bedside cognitive assessment showed a Mini Mental State
score of 18/30 and a Clock Drawing Test of 3/7.

21. CASE
STUDY
Examination on cranial nerves
• Cranial nerves examination revealed a fractionated smooth-pursuit with
slow and long latency saccades, spontaneous and evocated nystagmus
was absent.
• No evidence of pyramidal dysfunction.
• Primitive reflexes could be elicited:
1. glabellar tap sign was positive and bilateral palmomental reflexes were
present.
2. Strength was normal.
3. Cog-wheel rigidity involving the right hemibody and a bilateral moderate
bradykinesia in upper and lower limbs.
• Cerebellar examination revealed a moderate axial and appendicular
ataxia. These signs were formally assessed using the Scale for the
Assessment and Rating of Ataxia (SARA).

22. CASE
STUDY CT SCAN

23. What is the disease of this
case report?
Q

24. HUNTINGTON DISEASES
● Huntington's disease (HD) is a neurodegenerative disorder of the central
nervous system characterised by the presence of choreic abnormal
movements, behavioural or psychiatric disturbances and dementia.
● It is autosomal-dominant inherited and is caused by an abnormal Cytosine-
Adenine-Guanine (CAG) repeat (36 repeats or more) on the short arm of
chromosome 4p16.3 in the Huntingtin gene.

25. What modulation of the gene
expression can be used?
Q

26. RNA INTERFERENCE
● RNAi is a type of gene-silencing therapy.
● Decrease the production of faulty HTT protein.
● RNAi therapy is an approach to deliver miRNAs that degrade HTT mRNA so
that the amount of HTT protein decreases.
● Only Successful approach for Huntington diseases.

27. TREATMENT OF HUNTINGTON DISEASES

28. VECTORS
● The current approach for RNAi therapy is to deliver the miRNA with the help
of adeno-associated viral (AAV) vectors.
● These are modified viruses in which the disease-causing genes have been
removed and replaced by miRNA that binds to HTT mRNA.
● AMT-130
● VY-HTT01

30. Can Duchenne muscular
dystrophy be completely cured
by exon skipping ?
Q

31. INDUCTION OF EXON SKIPPING
● The mechanism behind exon skipping is a mutation specific antisense
oligonucleotide (AON).
● Exon skipping is being heavily researched for the treatment of Duchenne
muscular dystrophy (DMD).
● Successful treatment by way of exon skipping could lead to a mostly
functional dystrophin protein, and create a phenotype similar to the less
severe Becker muscular dystrophy (BMD)
● Eteplirsen and golodirsen are exon skipping drugs.

32. ANTISENSE-INDUCED OF EXON SKIPPING

33. GENE EDITING
● Genome editing, or genome engineering, or gene editing, is a type of genetic
engineering in which DNA is inserted, deleted, modified or replaced in the
genome of a living organism.
● Researchers have used CRISPR gene-editing and ZFN
technology technology to try to treat a person infected with HIV.
● Scientists in engineered human stem cells to mimic a rare form of natural
immunity to the virus and transplanted them into a man with HIV and blood
cancer.

34. Can we cure HIV with gene
editing?
Q

35. HOW DOES IT WORK ON HIV ?
● Case report on Berlin patient who has been cured from HIV
● He have lymphoma
● Received a haempoietic Stem cell Transplantation
Related Words with the concept
● Bi-alleic CCR5-delta 32
● ZFN editing technology
● CCR5 gene
● CCR5 / CXR4 – tropic virus (Both combination is also possible)

37.  New Blood | Northwestern Medicine Magazine
 Thalassemias | NHLBI, NIH
 Hemophilia | ASGCT - American Society of Gene & Cell Therapy |
 Thalassemia - Symptoms and causes - Mayo Clinic
 Genetic therapy for beta-thalassemia: from the bench to the bedside - PubMed (nih.gov)
 FIX It in One Go: Enhanced Factor IX Gene Therapy for Hemophilia B – ScienceDirect
 Hemolytic Anemia | Johns Hopkins Medicine
 How does gene therapy work?: MedlinePlus Genetics
 Gene therapy (sciencedaily.com)
REFRENCE

38.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5384355/
 https://en.wikipedia.org/wiki/Exon_skipping
 https://huntingtonsdiseasenews.com/rnai-therapies/
 https://www.ncbi.nlm.nih.gov/probe/docs/techrnai/
 https://medlineplus.gov/genetics/condition/huntington-
disease/#:~:text=Huntington%20disease%20is%20a%20progressive,a%20person's%20thirties%20or%20f
orties.
 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3736277/
 Thompson genetics textbook
REFRENCE

39. THANK YOU