Lecture 6 Dentistry Genetics 2024-2025 PDF

LECTURE 6 GENERAL BIOLOGY CODE: BAS131 FIRST YEAR DR WESAM SALAMA FIRST SEMESTAR 2024-2025  Chromosome mutation Numerical mutation (change in chromosomes number) Structural mutation (change in their structure) Abnormality in sex chromosomes ...

LECTURE 6 GENERAL BIOLOGY CODE: BAS131 FIRST YEAR DR WESAM SALAMA FIRST SEMESTAR 2024-2025  Chromosome mutation Numerical mutation (change in chromosomes number) Structural mutation (change in their structure) Abnormality in sex chromosomes  NUMERICAL chromosome MUTATION Numerical abnormalities are a type of chromosome defect. These types of birth defects occur when there is a different number of chromosomes in the cells of the body from what is usually found. So, instead of the typical 46 chromosomes in each cell of the body, there may be 45 or 47 chromosomes.  Numerical Chromosome Mutation associated syndrome 1- PALLISTER KILLIAN SYNDROME (PKs) (Isochromosome 12p syndrome) 2- DOWN SYNDROME (trisomy 21) 3- Patua SYNDROME (trisomy 13) 4- Edwards SYNDROME (trisomy 18)  PALLISTER KILLIAN SYNDROME (PKs) (Isochromosome 12p syndrome) TETRASOMY: Extra 2 copies of chromosome #12 with Isochromosome Pallister-Killian mosaic syndrome is a developmental disorder that affects many parts of the body. It characterized by:  facial features  intellectual disability  sparse hair  unusual skin coloring  hypotonia (muscles weakness)  Congenital diaphragmatic hernia Normal diaphragm Diaphragmatic hernia  Facial appearance: 1- high, rounded forehead 2- a broad nasal bridge with a short nose. 3- widely spaced eyes 4- low-set ears 5- wide mouth with a thin upper lip and a large tongue (macroglossia). 6- opening in the roof of the mouth (cleft paLate). 7- Extra finger or toe 8-heart defect  Oral manifestations: 1- Pallister lip 2- Macroglossia (large tongue) 3- Delayed eruption of primary teeth. 4- High arched-palate 5-cleft palate DOWN SYNDROME Down syndrome or Down's syndrome, also known as trisomy #21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21 It has mild to moderate intellectual disability Mental disorder Heart disease Thyroid disease Cancer as leukemia and testicular Constipation Imperforate anus.  Puffiness around eyes Burchfield spots on iris Small ears Fissured tongue Gap between first and second toe Palmar crease.  Oral manifestation: Gingivitis severe periodontal disease Early tooth loss Alkaline saliva leads to tooth erosion. Loss oral hygiene Retained primary and permanent teeth in mandible and maxillae Patau SYNDROME Also known as trisomy #13 (presence of extra copy of chromosome 13). Rarely survive 70% of the children die at 6 months. Suffers from heart, respiratory, brain, eye defects, and hearing disabilities. Oral manifestation: 1- Micrognathia 2- cleft plate or cleft lip  Edwards SYNDROME (Trisomy 18) Edwards syndrome It is caused by an extra copy of chromosome 18. It is a genetic condition in babies that causes severe disability. and babies born with the condition usually do not survive for much longer than a week.  Babies with Edwards syndrome may have: low birth weight small head (microcephaly) and jaw (micrognathia) an unusual-looking face and head unusual hands and feet (clubfeet) with overlapping fingers and webbed toes problems with feeding, breathing, seeing and hearing Heart and lung abnormalities Umbilical hernia Oral manifestation The major clinical features are 1. cleft lip/palate 2. high-arched narrow palate 3. Micrognathia 4. anterior open bite 5. posterior cross bite 6. taurodontism (small pulp cavities and large teeth).  Taurodontism Open bite Posterior cross bite YOU CAN ASK ANY QUESTION?  THANK YOU AND GOOD LUCK WISH ALL THE BEST TO ALL OF YOU. STUDY HARD I WILL MISS YOU DR WESAM SALAMA PROFESSOR OF BIOLOGY