Term
| Robertsonian translocation |
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Definition
Name the translocation: About 4%
46 chromosomes, chromosome 21q and chromosome 14 or 22
Occurrence shows no relation to maternal age
Relatively high recurrence risk in families |
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Term
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Definition
Very rare; only a part of the q arm of chromosome 21 in triplicate
A down syndrome patient with no cytogenetically visible chromosome abnormalities |
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Term
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Definition
| May be less able to overcome susceptibility to nondisjunction established by recombination system |
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Term
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Definition
| Recurrence risk of trisomy 21 or some other autosomal trisomy, after one such child has been born, is about___percent |
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Term
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Definition
Large deletion in chromosome 5p
Crying infants sound like mewing cats
1% of all institutionalized mentally retarded patients have this syndrome
Most cases are sporadic
10 to 15 % are offspring of translocation carriers
Many clinical findings due to haploinsufficiency of genes within band 5p15.2,
Cat’s cry results from deletion in band 5p15.3 |
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Term
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Definition
| Segmental aneusomy small deletions genetic imbalance can be detected by what methods? |
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Term
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Definition
| Haploinsufficiency of multiple contiguous genes |
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Term
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Definition
Sporadic condition
4 Mb deletion of chromosome 17p11.2
70 to 80% of all patients
Multiple congenital abnormalities
Mental retardation
SMS deletion through unequal recombination between near identical (99%) sequences
Reciprocal duplication seen in patients with milder and neurobehavioral phenotype |
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Term
| Charcot-Marie-Tooth Disease |
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Definition
Deletion of chromosome 17p11.2-12
Hereditary neuropathy with liability to pressure palsies (HNLPP) |
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Term
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Definition
Autosomal dominant syndrome
Microdeletion in chromosome 22q11.2
One of the most common cytogenetic deletions associated with clinical phenotype
Frequency: 1 in 2000 to 4000 live births
3000 kb deletion in chromosome 22q11
Removes approximately 30 genes
Smaller deletion seen in about 10%
Homologous recombination between low-copy repeat sequences |
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Term
| Haploinsufficiency of TBX1 gene |
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Definition
| codes for transcription factor involved in development of pharyngeal system |
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Term
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Definition
| deletion in 7q11.23 results in what disease |
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Term
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Definition
| deletion in 17q11.2 results in what disease |
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Term
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Definition
| deletion in 5q35 results in what disease |
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Term
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Definition
| deletion Yq11.2 results in what disease |
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Term
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Definition
produce mullerian inhibitory substance
suppresses formation of the paramesonephric ducts |
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Term
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Definition
| 10% of nonobstructive azoospermia results from interstitial deletions in |
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Term
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Definition
| AZFc encodes for ___(deleted in azoospermia |
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Term
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Definition
| Most genes on the inactive chromosome are transcriptionaly silent (10-15% can still be expressed and are usually located on ___ |
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Term
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Definition
| X chromosome inactivation center located to ___ and encodes for XIST gene |
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Term
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Definition
| produces a key regulatory noncoding RNA that is only expressed on the inactive chromosome and transcriptionally silent on the active X chromosome |
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Term
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Definition
| these autosome translocations are also nonrandomly inactivated |
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Term
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Definition
| is less frequent in live born but commonly found in spontaneous abortions |
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Term
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Definition
| which is more prevelant Turner's or Klinefelters |
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Term
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Definition
Tall and thin males with relatively long legs;Incidence is 1 in 1000 male births
Have Barr bodies
50% of all cases result from errors in paternal meiosis
Failure of normal Xp/Yp recombination.
Some result from errors in maternal meiosis
Appear normal until puberty signs of hypogonadism appear at puberty
Underdeveloped secondary sex characteristics
Infertile because of failure of germ cell development
Some psychological problems |
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Term
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Definition
Incidence 1 in 1000 male births
Not associated with clinical phenotypes
Phenotype
Tall
Attention deficit, hyperactivity, impulsiveness
Normal intelligence
Fertile
No increase in aggression or psychopathology
Result from paternal meiotic nondisjunction |
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Term
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Definition
Incidence 1 in 1000 female births
Somewhat above average stature, no abnormal phenotype
Fertile, but have Increased risk of chromosomally abnormal offspring
Abnormal behavior, IQ below normal |
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Term
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Definition
Average to above average intelligence
Worse social cognition skills if X chromosome derived from mother
Small ring X chromosomes are sometimes seen
Usually show mental retardation
Lack XIST gene overexpression of X-linked genes
A large ring chromosome with XIC phenotype similar to Turner syndrome
A small ring without XIC/XIST more severe |
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Term
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Definition
| Mutation in SOX9 gene SOX9 involved in testis formation |
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Term
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Definition
| Excess of DAX1 suppresses SRY and leads to ovarian development |
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Term
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Definition
Female or ambiguous external genitalia
Mutation in WT1 gene disrupts normal testicular development
9p deletion syndrome DMRT1 gene deletion. DMRT1 involved with gonad development |
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Term
| congential adrenal hyperplasia |
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Definition
Pseudohermaphroditism gonadal tissue of only one sex (autosomal recessive disorder arising from defects in enzymes for cortisol biosynthesis
46,XX with ambiguous external genitalia
Caused usually by |
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Term
| congenital adrenal hyperplasia |
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Definition
Group of AR inherited disorders relating to the adrenal gland
Characteristics
Cortisol and aldosterone deficiency
Androgen overproduction
Can affect both sexes.
Female Phenotype
Enlarged clitoris with urethral opening at the base (ambiguous genitalia, often appearing more male-like than female).
Internal structures of the reproductive tract normal.
With increased age deepening of the voice, the appearance of facial hair, and failure to menstruate at puberty. |
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Term
| male phenotype of adrenal hyperplasia |
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Definition
Infants no obvious abnormality
Affected males may appear to enter puberty as early as 2-3 years of age
At puberty, the testes are small.
Some forms more severe can cause adrenal crisis in neonates due to salt wasting.
Vomiting, dehydration, changes in electrolyte profile, cardiac arrhthmia
If untreated death within 1-6 weeks after birth |
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Term
| male pseudohermaphrodotism |
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Definition
| Deficiency of the steroid 5 a-reductase (converts testosterone to its active form) |
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Term
| androgen insensitivity syndrome |
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Definition
Lack of androgen receptors in target cells
Normal female external genitalia, blind vagina, and no uterus or uterine tubes
this is inherited in an X-linked recessive manner |
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Term
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Definition
if you get a frameshift or nonsense mutation Nonsense mutation or
Frame shift mutation
Near amino terminal end what type of thalassemia do you get |
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Term
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Definition
| nonsense or frameshift mutation near the carboxyl terminal results in what type of hemoglobin disorder? |
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Term
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Definition
| If ____ is removed, all genes of the cluster may remain intact but they are not expressed |
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