Structural- Genetics

monosomy

one member of a pair of chromosomes is missing

deletion

part of one chromosome is missing

addition

one chromosome has extra material on it

extra chromosome

have a third copy of one of the pairs

mosaicism

some cells have an extra copy but the rest do not

genetic syndromes

caused by some abnormality in the genes

teratogenic syndrome

caused by some foreign substance or microorganism on the developing organism

mechanically-induced syndrome

caused by stress on the body

idiosyncratic syndrome

unknown cause

sequences

multiple anomalies that arise in the same individual

malformation sequence

something inherent to the individual themselves leads to the changes

deformation sequence

something external starts a chain of events

disruption sequence

some physical factor interrupts normal development

associations

multiple anomalies present in one individual that don’t have the same cause and are not part of a sequence

prevalance

how common a problem is in the population or a portion of the population

incidence

how often the problem enters the population

hereditary

inherited from your ancestors

genetic

from your genetic material

congenital

present at birth

down syndrome

most common genetic form of developmental intellectual disability

fragile x syndrome

most common hereditary form of developmental intellectual disability

syndactyly

webbed

polysyndactyly

multiple webbs and/or extra digits

hypoplasia

incomplete development of an organ

hypertelorism

wide-set eyes

coloboma

gap in the structure of the eye

autosomal dominant

• at least a 50% risk

• parent with the trait has 1 dominant gene, but could have 2 dominant genes

penetrance

percentage of individuals with the gene who actually get the disease

expression

manner in which a disease can express once penetrance has occurred

autosomal recessive

• difficult to assess risk without genetic analysis of parents

• more severe, so rarer

x-linked

• can be dominant or recessive

• recessive are more common and more severe in males

genomic imprinting

• phenotype determine by sex of contributing parents

maternal inheritance

• DNA in mitochondria

• some mitochondrial genes are used to code development