a. The role of genetic causes of diseases. b. Common modes of genetic disorders such as single gene defect, polygenic inheritance, etc. c. Discuss the complex traits and diseases which predispose and modify common diseases. D. Describe the process of gene-gene interaction and gene-environment interactions.Multifactorial (Polygenic) “Environmental” influences act on a genetic predisposition . One organ system affected. - Environmental: Drugs, Chemical, Radiation, infections, etc.. Single gene Dominant/recessive pedigree patterns (Mendelian). Structural proteins, enzymes, receptors, transcription factors. Chromosomal Multiple organ systems affected Inherited or de novo. Continuum of penetrance. There is a continuum of penetrance from fully penetrant conditions, where other genes and environmental factors have no effect, through to low-penetrance genes that simply play a small part, along with other genetic and environmental factors, in determining a person’s susceptibility to a disease Single gene mutations, following classical Mendelian inheritance patterns Most of these are hereditary and familial. (High risks to relatives). Dominant/recessive pedigree patterns Some isolated cases due to new dominant mutations Structural proteins, enzymes, receptors, transcription factors MUTATIONS- are permanent disorders in individual’s DNA (essential single gene changes) in amount or function or both.  interfere e protein synthesis  responsible for causing illnesses, fall in two categories of genes: 1. Mutations in germ cells: are transmitted to the progeny and can give rise to inherited diseases. 2. Mutations in somatic cells – Not transmitted to progeny, but important in causation of malignant transformation and some congenital diseases Enzyme defect (Most of them, e.g. PKU- “AR”) Accumulation of substrate Lack of product Failure to inactivate a protein which causes damage Enzyme defect which increases drug susceptibility: G6PD Primaquine. Receptor/transport protein defect (Familial Hypercholesterolemia- “AD”). Structural protein defect (Marfan, Ehl-Dan)- “AD” Structure Function Quantity . 2. Mutations in somatic cells – Not transmitted to progeny, but important in causation of malignant transformation and some congenital diseases. MUTATIONS- are permanent disorders in individual’s DNA (essential single gene changes) in amount or function or both.  interfere e protein synthesis  responsible for causing illnesses, fall in two categories of genes: 1. Mutations in germ cells: are transmitted to the progeny and can give rise to inherited diseases.

1. Periapical diseases

2. • Differential diagnosis?
• Describe the radiograph?
• Accordingly what are the
possible signs and
symptoms that can be
associated with each
condition
PICTURE 1
PICTURE 2
PICTURE 3

3. A
B C
MATCH

4. IDENTIFY

5. Its time for “who am I ?”
• Select a representative.
• The representative will pick a card.
• The representative will have all the
necessary data of the pathological
condition on the card.
• The group will ask the
representative yes or no questions
to reveal the pathological
condition.

6. Case
1
• Nature of the condition:
• Inflammatory process ‘Severe form of cellulitis’
• Etiopathogenesis:
• Infection seeks the path of least resistance (thinner lingual
cortical plate). The apices of these teeth are situated below the
mylohyoid ridge. Infection reaches submandibular space from
where it spreads to involve other spaces such as sublingual,
submental spaces (true Ludwig’s angina)
• Signs & symptoms, complications:
• Elevation, enlargement, and protrusion of the tongue (woody
tongue)
• Firm, painful swelling in the upper part of the neck enlargement
and tenderness of the neck above the level of the hyoid bone(bull
neck).
• Dysphagia and difficulty in breathing
• High fever, dyspnea, tachycardia and leukocytosis
• May lead to suffocation and death
• Management:
• Airway management, IV antibiotics, incision and drainage,
tracheostomy
Ludwig’s Angina

7. Case
2
• Nature of the condition:
• Inflammatory process ‘Severe form of cellulitis’
• Etiopathogenesis:
• serious complication of orofacial infections or any
infections involving “danger triangle of the face”
due to thrombus formation in the cavernous sinus or
it’s communicating branches.
• The infection usually involves one side but can
easily spread to the otherside.
• Signs & symptoms:
• Edematous periorbital enlargement with
involvement of the eyelids and conjunctiva.
• Management:
• IV antibiotics
Cavernous sinus thrombosis

8. Case
3
• Nature of the condition:
• Inflammatory process
• Etiopathogenesis:
• Diffuse edematous spread through fascial
spaces of the soft tissue
• Signs & symptoms:
• Fever, malaise, loss of appetite
• Firm, painful diffuse swelling
• The overlying skin is inflamed and red
• Regional lymphadenitis
• Management:
• IV Antibiotics
• Incision & drainage
Facial cellulitis