Oral pathology ch.6 genetics
Terms in this set (72)
a related group of symptoms that occurs together.
the genetic composition or makeup (a combo of allels on homologous chromosomes
the observable appearance of a genetic makeup
formed by tightley coiled chromatin
lyon hypothesis (bar body)
during embyronic development one of the females X chromosomes is inactivated and forms a dark dot found on the periphery of a nucleus. this can be seen microscopically and can afect the type of diseases carried on x chromosomes.it determineswhich x chromosome diseases can be passed on
location of a gene on a chromosme
trait expresses whether or not homozygous or heterozygous. ex HH hh or Hh
gene for the trait must be present in bothallels in order to express. ex HH or hh
when a person does not exhibit the disease but has the one allele for the disease and therefore can pass on to offspring
occur at DNA level
alternations in the number of chromosomes
when a cell loses or gains genetic material during early divison. They will have a variable % of abnormal cells with normal cells because the alternation occurs not with the first dividing cell but therafter (after normal cells have already been made). only abnormal cells will continue to divide with the alternaton.
a pair of chromosomes with an extra chromosme.
ex. Down Syndrome. occurs when an extra copy of chromsome 21 occurs.
Syndrome characterized by slanted eyes, flattened nose bridge, Heart abnormalities which may require premedications. They often have a large fissured tongue
Small abnormally shaped teeth, 90% have perio disease, hypodontia, anomalies in eruption, crowding, large fissured tongue
What are some oral manifestations of Down Syndrome (trisomy 21)
Heart defects (Premeds?) Frequent recare, OHI for both patient and care-giver, send home written instructions, bite-block, assistance to retract tongue
what are some dental implications of Downs Syndrome (Trisomy 21)
monosomy of X chromosome: so only one X chromosome
short in stature, webbing of the neck, edema of hands/feet, abscence of bar bodies in all cells
Klinefelter Sydromme (Testicular dysgenesis)
Nondisjuntion of X chromosomes (XXY or XXXXY), Greater number of x's=more problems. They have deficient testosterone
Klinefelter (testicular dysgenesis)
genetic disorder characterized by deficient testosterone, tall, long arms and legs, may have mitral valve prolapse, hypoplastic maxilla, taurodontism, large pulp chamber, short roots
Klinefelter (testicular dysgenesis)
this genetic disorder has oral conditions that include a slightly hypolastic maxilla (underdeveloped and taurodontism, a large pulp chamber with short roots)
cri du chat syndrome
a rare disorder characteriaed by deletion of chromosome 5 arm. they have small teeth, delayed eruption, malocclusion and a high vault. they have cat-like cry at birth and are mentally retarded
Autosomal dominant Inheritance
single gene abnormalities, may occur when 1 overriding gene in a pair is present, phonotype occurs in every generation males/females equally affected, 50% chance Directly from one generation to the next. ex. Hh lack of penetrance, mild expressivity, seldom lethal
autosomal reccesive inheritence
typically transmitted thru non affected carriers, increase chance in families consanguineous(marry w/in family) most produce biochem defects that produce metabolic disease. individual homozygous-traits expressed, individual heterozygous-trait is not expressed
This supports the Lyon Hypothesis. For women who have two x chromosomes this type of inheritence is only seen clinically if they are homozygous. however the defetive gene will always be expressed this way on males because they only have one x chromosome(the condition or trait will be seen clinically).
characteristics or traits that are inherited by the praticipation of several genes
Autosomal dominant disorder where there is decrease in number of neutrophils every 21-27 days. episodes 2-3 day More susceptible to oral diseases such as severe ulcerative gingivitis/periodontitis (u get sick- fever, malaise, sore throat, cutaneous infection)
PLS (Papillon-Lefevre Syndrome)
autosomal recessive charterized by red, scaly hyperkeratosis of the palms of hands/soles of feet.(rest of life) they have sever gingivoperiodontal disease after eruption (all teeth are usually lost by age 14 primary teeth by 2). They have high number of actinbacills actinomycetemcoomitans-immunodeficiency (WBC) decr chemotaxis
Focal Palmoplantar and gingival hyperkeratosis
autosomal dominant inheritance pattern chracterized by hyperkeratinazation of palms/soles and labial/lingual gingiva, increases w/ age bcms localized w/callus formation (rest of the O/C normal, changes start in childhood, free gingiva not affected)(attatched gingiva looks white with keratin
several inherited syndromes exhibit this. gingival hypertrophy develops early in life Within a few years teeth covered by gingiva. tissue is usually symetrical. Associated syndromes include epilepsy Rx phenytonin-cz more gingival enlargement (collagenization of fibrous C/T, composed of firm tissue w/granular corrugated surface
painless form of fibrous dysplasia. Spongeybone is replaced by fibrous tissues that contain multinucleated giant cells. Eyes tend to tilt upward like angels in religious paintings. Radiographs will show chracteristic soap bubbles or multilocular appearnce. the areas are occupied by theese mutlinucleated giant cells. they wil have bilateral giant cheeks
Ellis-Van Creveld Syndrome (chronodroectodermal dyslpasia)
autosomal recessive inheritence, People have extra digits. Usually have fusion of anterior maxillary gingiva to the lip (causign them to lack an anteriors vestibular sulcus) and have one central tooth in place of 2 central incisors. They also have conical shaped teeth with ename hypoplasia.
CCD (cliedocronial Dyslpasia)
Autsomal Dominatn, spontaneus mutation. They have a mushroom cranium, lng narrow neck. They have an underdeveloped premaxilla (pseudoprognathism), High narrow palate, most striking oral manifestation is supernumerary teeth and multiple cysts around tgese teetg.
gardner syndrome (familial colorectal polyposis)
autosomal dominant disorder. osteomas of the facial Skelton (frontal bone, mand, maxi)obliterates sinuses & cz facial asymmetry, odontomas in jaw bone. very commonly get polyps in intestines that bcm malignant af/ age 30
Mandibulofacial Dystosis (Treacher Collins Syndrome)
Birdlie face, always hearing loss/misplaced abnormal ears. a high vault is normally present. have small manible, malocclusion, gingival disease D/D of cranial bones & hypoplasia of the lower part of face. mandibular body under developed, eyes slant downwards, teeth crowed and malposed, high vaulted palate, deafness
Nevoid Basal Cell Carcinoma Syndrome
Autosomal Dominant Inheritence, mild hypertelorism (increased space between eyes), mild prognathism, frontal and parietal enlargement, mental retardation, cleft lip/palate
blue sclera of eyes, abnormally formedbones that can be so fragile that babies die in womb due to broken long bones. Oral manifestation is Dentinogenesis imperfecta (opalescent teeth where enamel breaks off from defective dentine)
what kind of inheritance pattern is torus mandibularis and palatinus
found on buccal, a single, multiple, unilateral, or bilateral increased densitiy/growth of bone
environmental and genetic elements influence a symptom. this is seen with with cleft palate and lip. Maternal smoking, alcohol consumption, certain drugs and folic acid deficiency occurs.
Hereditary hemorrhagic telangiectasia (osler-redu-parkes weber syndrome)
autosomal dominant. Multiplecapillary dilations of skin and mucosa. Care should be taken because lesions inmouth can bleed profusely if traumatized. often found on the tongue
multiple mucosal neuroma syndrome
Autosomal Dominatn. Tall stature with thick large lips, medullary carcinoma of the thyroid gland is common as well as mucosal neuromas which are found on the lips, anterior dorsum of the tongue and buccal mucosa.
Neurofibromatosis of Von Recklinghauses
Autosomal Dominant inherritance. Characterized by multiple neurofibromas, palpules. Malignatn transformation can occur. There may be oral lesions on lateral border of tongue.
Autosomal dominant inheritance. Have polyps in small intestines & rarely become malignant. Most striking characteristic is melanotic macular pigmentation on eyes, nose and mouth, Lips, Buccal mucosa of 98% pt (diminishes w/age)
White sponge nevus
Autosomal Dominant Inheritance, complete penetrance present at birth or starts at puberty Characterized by white, corrugated, soft, folding of buccal oral mucosa, usually bilateral. Due to a thick layer of keratin.
Only enamel affected, no associated systemic defects. There are 4 types based on stage of developent of enamel that is defect.
hypoplastic amelogenesis imperfecta, tooth enamel does not develop to a normal thickness. failure of ameloblast to lay down enamel matrix. Characteristics: pitted, local, smooth, rough. pitted auto-dominant variety
Hypocalcified amelogenesis imperfecta, an uncommon form characterized by yellow to orange soft enamel fractures easily leaving exposed dentin. moth-eaten, ant. open bite
hypomaturation amelogenesis imperfecta. enamel of mottled appearance but normal thickness. composed of lg. amount of enamel matrix but enamel is softer than normal. tips of instruments penetrate enamel & it chips easily form crowns of teeth.
hypoplastic hypomaturation amelogenesis imperfecta, associated with taurodontism, looks yellow-brown to pitted. single rooted teeth have large pulp chambers
Type I deals with osteogenesis imperfecta. Type II hereditary opalescent dentin. Dentin is very soft which causes chipping of enamel & tooth attrition. teeth can be worn down to alveolar process. bulbous crowns with a color that varies from opalescent brown to brownish blue. 20% pt also have enamel hyposplasia. Dfficutl to Tx bc teeth is so week it is hard to hold restoration. no pulp chamber or root canal seen, defect of odantoblast.
autosomal dominant. Two types. Type I-Radicular: causes disorgination of appostion of root dentin due to disturbance in HERS. The teeth are rootless. teeth exfoliated prematurely.
Type II: Coronal: mostly affects decidious teeth only.Priimarmy teeth are transulcent with an amber color. Adult teeth appear normal. Looks but is not associated with dentinogenesis imperfecta. in primary teeth. thistle shape & bow tie pulp chamber.
hypohidrotic ectodermal dysplasia
a genetic heterogenecity, may be inherited in more than one way. Characterized by hypodontia, hypotrichosis (decreased hair), and hypohidrosis (decreased sweating-could die from overheating) sever form of ectodermal dysplasia. frontal bossing, depressed nasal bridge, protuberant lips, no scalp hair.
autosomal recessive Decreased in serum alkaline phosphatase with increase urinary & plasma phosphoethanolamine cz agenesis or abnormal cementum formation. Teeth do not have cementum and are exfoliated prematurely (esp mand incisors) Only affects primary dentition. + improper formation of mature bone, but rarely affect permanent teeth or Prim/molars
hypophosphatemic Vitamin D-resistant rickets
x-linked dominant. Low serum levels of phosphorus.(short stature) oral manifestation: large pulp chambers, large pulp horns, cracks in dentin all the way to DEJ that may allow bacteria to get in and cause pulpal infections
pegged or absent max. lat. incisors
A/D variable expressivity, lat incisors may be small, cone or peg shaped. or may be congenitally missing one side or both. 1%-3% prevalence in white population. premolars congenitally lacking 10% -20% of affected individuals
occurs because of failure of hertwigs epithelial root sheath to proliferate and form roots. Only occurs in multiple rooted teeth. Teeth are blocky looking, pyramidal with large pulp chambers. Often seen in people with down syndrome.
Type III snowcapped type (amelogenesis imperfect)
hypomaturation of the surface enamel of occlusal third of all teeth in both dentition. maxi teeth more severely affected. enamel is of regular hardness and smooth.
lack of penetrance
prevalence of individuals with a given genotype who manifest clinically the phenotype associated with that trait. (# of people that have gene for green hair but don't show the green hair)
(some with neon green hair others with light green hair) degree of clinical manifestation of a trait or characteristic
what are 4 patterns of inheritance
autosomal dominant, autosomal recessive, x linked dominant, x linked recessive
x-linked inheritance *
man's x-chromosomes is transmitted to all of his daughters and non of his sons
when a condition has more than one inheritance pattern and differences in the degree of clinical manifestations for each of the inherited varieties
alterations in structural proteins are inherited as dominant traits alterations in enzymatic proteins are inherited in a recessive manner
resessive genetic heterogeneity
individual must be homozygous for the trait for it to be seen (gg) more dangerous
both genes are exhibited
single gene inheritance
characteristics that are governed by the action of on gene
traits that are inherited by the participation of several genes show greater clinical variation than those inherited through single gene action, tooth shape and form, eye color
treat for cyclic neutropenia?
Tx with granulocyte colony- stimulating factor (G-CSF) determine frequency of cycles, preventive antibiotic should be started when neutrophil count is normal to protect against opportunistic infections
chronic neutropenia AKA Kostmann syndrome
autosomal recessive, intraoral manifestation: similar to cyclic neutropenia but constant, responsible gene is unknown, Tx w/ periodic G-CSF
Café au lait pigmentation seen in first decade of life in 90% of pt's and generally precedes development of?
neurofibromas (papules of various sizes) of neurofibromatosis of von Recklingausen