How do mutations affect health and craniofacial development Flashcards
only factor that has been linked to an increased chance of having a baby with Down syndrome resulting from nondisjunction or mosaicism.
Maternal age
Most cases of aneuploidy originate in _______and the risk rises with maternal age
female meiosis I
Dominant, Recessive, Codominant are ____ disorders
single gene disorders
Multiple genes, gene-environment are ____ disorders
Multifactorial or Complex disorders
Caused not by a single major mutation but by interacting genetic and environmental risk factors; Most of the common diseases, from allergies to diabetes and coronary heart disease
Multifactorial diseases
T/F: Heredity is not a factor in trisomy 21 (nondisjunction) and mosaicism
True
T/F: About half the children with Down syndrome are born with some type of congenital heart defect.
True
Aneuploidy, Rearrangements/Translocations, Deletions, Insertions, and Duplications are examples of ____ disorders
chromosome disorders
____ is a sign of down syndrome; single deep crease across the center of the palm
transverse palmar crease
Intellectual disability and delayed development, Small head size (microcephaly); Low birth weight, Weak muscle tone (hypotonia), Transverse palmar crease, Some have heart defects are characteristic of
Cri du chat
full or partial copy of a chromosome like 21 attaches to another chromosome, usually chromosome 14
translocation
T/F: due to higher birth rates in younger women, 80% of children with Down syndrome are born to women under 35 years of age.
True
Heart defects, spinal defects, heartburn, sleep apnea, endocrine problems, dental problems, and seizures are common in patients with _______
down syndrome
_____ is derived from the frontonasal prominence
Nasal Septum
_______ separates the nasal cavity from the oral cavity
Secondary palate
_____ are derived from the maxillary process of the first pharyngeal arch
Palatal shelves
________ is needed for swallowing (feeding)-taste-vomiting-breathing-speech
Secondary palate
What is the most common mechanism for Down syndrome?
Nondisjunction
Down syndrome is a _____ at chromosome number ______
Trisomy at 21
Caused by chromosome breakage or by recombination between mispaired chromosomes during meiosis
Chromosomal rearrangements
Down syndrome is a type of ______ (chromosome disorder)
aneuploidy
____ occurs when chromosomes don’t separate properly
Nondisjuction
Widely set eyes (hypertelorism), Low-set ears, Small jaw (micrognathia)•Rounded face (moon facies), epicanthal folds, broad nasal bridge, downward-slanting palpebral fissures are common facial features associated with _____
Cri du chat
T/F: Severe dominant diseases are often caused by a new mutation
True
The average child is born with an estimated _____ new mutations that were not present in the parents
100-200
Epicanthal fold, upslanting palpebral fissures, low-set small folded ears, short neck, flattened nasal bridge, brushfield spots are key facial characteristics of down syndrome
Down syndrome
______ mutations are expressed in heterozygotes, who carry a single copy of the mutation
Dominant
Low muscle tone, small stature, cognitive delay, and transverse palmar crease are signs of ____
Down syndrome
An aberration in chromosome number caused by faulty segregation of chromosomes during mitosis or meiosis
Aneuploidy
What is the least common mechanism for Down syndrome?
mosaicism
1 in ____ infants is born with aneuploidy
1 in 400 infants
_____ is a common example of chromosomal rearrangements
Cri-du-Chat syndrome
Infants with this condition often have a high-pitched cry that sounds like that of a cat; characteristic of Cri du chat syndrome
Cat’s cry
1 in ____ infants is born with a diagnosable genetic condition that can be attributed to a single major mutation
1 in 50 infants
T/F: Spinal problems. Some people with Down syndrome may have a misalignment of the top two vertebrae in the neck (atlantoaxial instability). This condition puts them at risk of serious injury to the spinal cord from overextension of the neck.
True
T/F: Only chromosomal rearrangements that change the copy number of genes or that break up an important gene are likely to cause disease
True
