Diseases Flashcards
- Features: dysmorphic faces, simian crease in palm of hand, sandal gap, clinodactyly, brushfield spots on iris, protruding tongue, low set ears
- Comorbidities: leukemia (from GATA1), Dementia (BAPP gene on chromosome 21) -47 chromosomes including an extra copy of the small, acrocentric chromosome 21 - Trisomy 21
Down Syndrome
What are the ways to get Down Syndrome?
- Trisomy 21
- Robertsonian Translocation
- 21q21q translocation
- Mosaic Down Syndrome
- Partial Trisomy 21
How does trisomy 21 occur?
- Features: dysmorphic faces, simian crease in palm of hand, sandal gap, clinodactyly, brushfield spots on iris, protruding tongue, low set ears
- Comorbidities: leukemia (from GATA1), Dementia (BAPP gene on chromosome 21) -47 chromosomes including an extra copy of the small, acrocentric chromosome 21 - Trisomy 21
- 90% maternal nondisjunction during meiosis 1 [1+1+1] - Increase risk with age
- 10% paternal nondisjunction during meiosis 2 [2+1] - Low reoccurrence risk for a second child
What is seen in the Robertsonian Translocation in Down’s Syndrome?
Robertsonian translocation between 21q with 14 or 22
- not from maternal age
- 95% spontaneous abortion, 5% live to 1 year old - Mental retardation, failure to thrive, severe malformation of the heart - Risk with increase maternal age - Micrognathia, overlapping fingers, rocker bottom feet - Trisomy 18 - 47, XY+18
Edwards Syndrome
- Usually lethal in utero
- Due to increase in maternal age
- Cleft lip/palate**, microcephaly, microphthalmia, polydactyly, hernia, rocker bottom feet
- Hands clench with 2nd and 5th digits overlapping 3rd and 4th
- Trisomy 13 - 47, XY+18
Patau Syndrome
- Chromosome 5p deletion
- autosomal deletion syndrome
- 10-15% reciprocal translocation
- mewing cry, microcephaly, hypertelorism, epicanthus, antimongoloid slant eyes, most are severely retarded
- deletion of part of the distal short arm of chromosome 5 designated 46,XY,del(5p)
Cri du Chat
- autosomal deletion syndrome
- 10-15% reciprocal translocation
- mewing cry, microcephaly, hypertelorism, epicanthus, antimongoloid slant eyes, most are severely retarded
Cri du Chat
-Chromosome 5p deletion
Cri du Chat
- Chromosome 17p11.2 deletion
- Deletion of RAI1 gene (retinoic acid needed for normal CNS development)
- Delayed speech/language skills, behavioral problems, sleep disturbances
Smith-Magenis syndrome (SMS)
- Deletion of RAI1 gene (retinoic acid needed for normal CNS development)
- Delayed speech/language skills, behavioral problems, sleep disturbances
Smith-Magenis syndrome (SMS)
-Chromosome 17p11.2 deletion
Smith-Magenis syndrome (SMS)
- duplication of PMP-22 gene (peripheral myelin protein) located in chromosome 17p11.2-p12
- Demyelinating neuropathy, distal leg wasting and atrophy
Charcot-Marie Tooth (CMT)
- Demyelinating neuropathy, distal leg wasting and atrophy
Charcot-Marie Tooth (CMT)
- duplication of PMP-22 gene
Charcot-Marie Tooth (CMT)
- Autosomal Dominant microdeletion of 22q11.2
- (CATCH 22) Cardio problems (tetralogy of Fallot)
- Abnormal facies
- Thymus missing or underdeveloped (t-cell deficiency)
- Cleft Palate hypoparathyroidism/hypocalcemia
Di George
Cardio problems (tetralogy of Fallot)
- Abnormal facies
- Thymus missing or underdeveloped (t-cell deficiency)
- Cleft Palate
hypoparathyroidism/hypocalcemia
Di George
- Autosomal Dominant microdeletion of 22q11.2 -
Di George or VCFS
- Autosomal Dominant microdeletion on chromosome 22q11.2
- Palate velum (high arch), cleft palate, bifid uvula, cardiac disease, poor socialization, poor coordination
Velocardiofacial Syndrome (VCFS)
- Inversion/duplication of chromosome 22q11.2
- tetrasomy
- ocular coloboma, congenital heart defects, craniofacial anomalies, moderate mental retardation
Cat-Eye Syndrome
-Inversion/duplication of chromosome 22q11.2
Cat-Eye Syndrome
(1) 45X, 50% of karyotypes
(2) 46X i(Xq), 50% of karyotypes
(3) Webbed neck, coarctation of aorta, streaked ovaries, widely spaced nipples, amenorrhea, infertility
(4) Hydrops Fetalis
(5) Cystic Hygroma
Turner Syndrome
(1) 47XXX, 48XXXX, 49XXXXX
(2) increase in SHOX gene
(3) Severity of mental retardation increases with # of Xs
Polysomy X
(1) Paternal non-disjunction disorder (meiosis 2)
(2) more SHOX = tall
(3) Slightly low IQ
47 XYY
(1) 47XXY
(2) Tall/thin
(3) High LH and FSH
(4) Gynecomastasia
(5) Infertile
(6) Hypogonadism and feminized characteristics
Klinefelter
- Autosomal Dominant
- Mutation in WT1 gene on chromosome 11p13
- Nephropathy, complete gonadal dysgenesis (XY female), risk of gonadal blastoma
Fraiser’s Syndrome
- Autosomal Dominant
- Chromosome 11p13
- Mutation in WT1 gene
- XY male with pseudohermaphroditism
- loss of playfulness, decreased appetite, growth delay, anuria,
- mesengial renal sclerosis, Wilm’s tumor, ambiguous external genitalia
Deny’s Drash
- Chromosome 11p13 Mutation in WT1 gene
Deny’s Drash or Fraiser
(1) Duplication of DAX-1 on Xp21.3
(2) Suppression of SRY (not deleted or mutated)
(3) Ovarian development
Sex Reversed 46 XY (females)
(1) Autosomal Dominant
(2) SOX9 gene mutation on chromosome 17q
3) Lethal skeletal malformation
(4) Die at birth or right after
(5) duplication SOX9 = XX male
(6) mutation SOX9 = XY female
Camptomelic Dysplasia
(1) Mutation CYP21 gene on chromosome 6
(2) 21-hydroxylase gene
(3) Virilization of infants due to increased androgens (Females with male characteristics, males with increased male characteristics)
Congenital Adrenal Hyperplasia (Female Pseudohermaphrodite)
(1) Deficient in 5 alpha-reductase
(2) Ambiguous genitalia, blind vagina/small penis
Male Pseudohermaphroditism
(1) X-linked
(2) Deletion of gene coding for Androgen Receptor
(2) 46XY but completely female looking
(3) Blind vagina, no uterus/uterine tubes, infertile, undescended testes in abdomen
Complete Androgen Insensitivity Syndrome (AIS)
(1) Deletion of 15q from paternal
(2) Neonatal hypotonia, small handsand feet, mild mental retardation, hypogonadism, non-stop eating
Prader Willi Syndrome
(1) Deletion of 15q from maternal
(2) Mutation in Ube3A (ubiquitin protein ligase)
(3) decrease in neuronal signals and synaptic development
(4) puppet like movements, inappropriate laughter and happiness, severe MR, microcephaly
Angelman Syndrome
(1) Extra isochromosome 12p (tetrasomy 12p)
(2) poor muscle tone, thin upper lip/thick lower lip, short nose, severe MR, coarse facies
Pallister-Killian
- rare neurodevelopmental disorder
- Deletion of 26 genes on chromosome 7q
- one of the deleted genes is elastin
- elfin face, cheerful demeanor, loves music, ease with strangers, aortic stenosis, hypercalcemia
William’s Syndrome
- Deletion of 26 genes on chromosome 7q
William’s Syndrome
(1) Chromosome 11p15
(2) IGF2, CDKN1C, H19, HCNQOT1
(3) large babies, macroglossia, wilm’s tumor, omphalocele
Beckwith-Wiedeman
Y linked gene required for normal spermatogenesis
USP9Y
section DAZ genes on Y chromosome encode RNA-binding proteins
AZF (azoospermia factor)
histone variant causing silencing of X chromosome
macroH2A
gene that encodes noncoding RNA to silence an X chromosome expressed only from the allele of the inactive X
XIST
gene essential for the development of the skeleton, particularly growth and maturation of bones in arms and legs
SHOX
gene on Xp21.3 coding a transcription factor that plays a dosage sensitive role in determination of gonadal sex
DAX1
gene located on 17q24 required for normal testis formation
SOX9
gene located on 11p13 coding for Wilm’s tumor suppressor gene
WT1
Trisomy 21
Down Syndrome
Trisomy 18
Edwards Syndrome
Trisomy 13
Patau Syndrome
How often does Down Syndrome occur?
Every 1 child in 800
What is the major cause for concern in Down syndrome?
mental retardation
These are health conditions seen in what disease?:
- Congenital heart disease (in one third of individuals), one fourth of the liveborn infants with heart defects die before their first birthday
- Hearing problems -
Intestinal problems, such as blocked small bowel or esophagus
- Celiac disease
- Eye problems, such as cataracts
- Thyroid dysfunctions
- Skeletal problems
- 15-fold increase in the risk of leukemia (GATA1 mutations)
- Dementia-similar to Alzheimer disease (bAPP gene on chr21)
Down Syndrome
If you saw any of these karyotype results, what would the patient have?
Karyotype is 46,XX or XY,rob(14;21)(q10;q10); also use der(14:21)
Down Syndrome
Which Down Syndrome has no relation to maternal age and a relatively high reccurence risk?
Translocation Down Syndrome
What are 3 different chromosomal abnormalities in Dwon syndrome?
- 21q21q translocation
- Mosaic Down syndrome
- partial trisomy 21
-autosomal deletion syndrome
Cri du Chat
- Deletion of RAI1 gene (retinoic acid needed for normal CNS development)
Smith Magenis Syndrome (SMS)
- duplication of PMP-22 gene
Charcot Marie Tooth
autosomal dominant microdeletion (x2)
Di George or Velocardiofacial Syndrome (VCFS)
Inerversion/duplication
Cat-Eye syndrome
Mutation in WT1 gene (x2)
Fraiser’s Syndrome or Deny’s Drash
Duplication of DAX-1 or Suppression of SRY
Sex-reversed 46XY females
SOX 9 mutation
Camptomelic Dysplasia
mutation in CYP21 gene
Congenital Adrenal Hyperplasia (Female Pseudohermaphrodite)
What are the 4 chromosomal abnormalities in Down Syndrome?
- Robertsonian translocation -21q21q translocation -Mosaic -Partial trisomy
X disorder not abnormal phenotypically, above average in stature, maternal age effect, may have only a slight mental deficiency
47XXX
- Inversion on chromosome 8
- common with Hispanincs in the Southwest US
- lethal condition caused by severe cardiac abnormalities and mental retardation
- Founder Effect
Recombinant 8