Disease Flashcards
Prader Willi Syndrome Symptoms
- excessive eating
- short stature
- hypogonadism
- some degree of intellectual disability
Prader Willi Syndrome Cause
del(15q11-q13) on paternal chromosome. ( PWS region is methylated on maternal 15)
Angelman Syndrome Symptoms
- short stature
- severe intellectual disability
- spasticity
- seizures
Angelman Syndrome Cause
del(15q11-q13) on maternal chromosome. (AS UBE3A region is methylated on the paternal 15)
Spinal Muscular Atrophy
Mutation in an unstable region 5q13
DiGeorge Syndrome
del(22q11.2)
absent or hypoplastic thymus and
parathyroids, congenital heart
disease
Macrocephaly and autism
caused by duplications on 1q21
Microcephaly and schizophrenia
caused by deletions on 1q21
Trisomy 18 symptoms
Small for gestational age, microcephaly, clenched hands with overlapping fingers, rocker bottom feet
Turner syndrome
45, X most common chromosome abnormality in SABs, 99% of fetuses do not make it to full term. 1/2500 female live births, short stature, webbed neck, coarctation of aorta, normal intelligence, infertility
What are the Turner Syndrome karyotypes?
45, X
46, X, i(Xq) (paracentric inversion)
mos 45, X/46, XX
mos 45, X/46, X, i(Xq)
Klinefelter Syndrome
47, XXY. 1/1000 liveborn males.
Sx: tall, hypogonadism, underdeveloped secondary sexual characteristics, learning disabilities, hypospadias, gynecomastia, infertility.
50% comes from maternal meiotic error, 75% of which is meiosis 1- maternal age effects
rec(8)
Derived from an inv(8)(p23.1q22.1) Leads to trisomy 8q22.1 and monosomy 8p23.1
Sx: Developmental delay, congenital heart disease, thin upper lip
Founder effect- San Luis Valley 2-300 years ago
Aniridia
inv(11)(p13p15) paracentric inversion
Miller-Dieker syndrome
del(17p13.3)
lissencephaly (agyria)
profound intellectual disabilities
Smith-Magenis syndrome
del(17p11.2)
Potocki-Lupski Syndrome
dup(17p11.2)
Hereditary Neuropathy with Liability to Pressure Palsies (HNPP)
del(17p12)
Charcot-Marie-Tooth Neuropathy, type 1A
dup(17p12)
17q21.31 recurrent microdeletion syndrome
del(17q21.31)
Alagille syndrome
del(20p12)
Cat-Eye Syndrome
dup(22q11)
X-Linked Ichthyosis
del(Xp22.3)
Cystic Fibrosis (allelic heterogeneity)
Caused by a mutation of the CFTR gene. If the mutation is deltaF508 it causes more severe pancreatic symptoms than R117H mutation, but has smaller effect on lungs. This means that other factors account for variability in lung sx.
Alzheimer’s Disease
Presinilin genes on chromosomes 1 and 14.
APP gene on chromosome 21
APOE gene on chromosome 19
IDIC 15 (Maternal)
Caused by isodicentric inversion duplication. Leads to autism, seizures, hypotonia. Non-dymorphic.
Interstitial duplication on maternally derived chromosome 15
Leads to autism, seizures, hypotonia. Non-dymorphic.
Jacob’s Syndrome
47 XYY.
Sx: Tall, learning disabilities, autism, behavioral/emotional issues.
1/1000 male births
Triple X Syndrome
47 XXX
Sx: Tall, learning disabilities, seizures, kidney abnormalities
1/1000 newborn girls
Androgen Insensitivity Syndrome
46XY. X-linked mutation in AR gene. Can lead to undervirilization or even complete sex reversal
5-Alpha-reductase deficiency
46XY. X-linked mutation in AR gene prevents testosterone from being converted to dihydrotestosterone. This leads to undervirilization with greater virilization during puberty
Denys-Drash and Frasier syndromes
46 XY. Mutation in WT1 gene (a transcription factor for SRY gene) causes sex reversal. Other sx- Wilms tumor and kidney issues
Congenital Adrenal Hyperplasia
46 XX with ambiguous genitalia due to 21-hydroxylase deficiency. Also causes salt wasting with decreased Na, Cl and increased K
Achondroplasia
Autosomal Dominant
Mutation of FGFR3 on chromosome 4p16.3
Causes rhizomelic limb shortening and genu varum
80% new mutation with paternal age effect
Retinoblastoma
Autosomal Dominant
Mutation of RB1 gene on chromosome 13
90% penetrance
Neurofibromatosis type 1
Autosomal Dominant
Causes cafe au lait spots, neurofibromas
Mutation of the NF1 gene on 17q11.2
Autosomal dominant, but need to acquire a mutation on the other allele to show phenotype
Tuberous Sclerosis
Autosomal Dominant
Hypopigmented patches, angiofibromas, lung, heart, kidney issues
Cause by loss of function mutation of TSC1 (9) and TSC2 (16)
Osteogenesis Imperfecta Type 1
Autosomal Dominant
Causes multiple fractures, mild short stature, adult onset hearing loss, blue sclera
Mutation of COL1A1 on 7q21.3
Marfan Syndrome
Autosomal Dominant
Causes aortic root enlargement, ectopia lentis
Mutation of FBN1 gene on 15q21.1
Huntington Disease
Autosomal Dominant, Anticipation
More than 40 CAG repeats in exon on 4p16.3
Earlier onset if paternal in origin
Myotonic Dystrophy
Autosomal Dominant, Maternal anticipation
More than 50 CTG repeats in 3’ UTR of MPK gene on 19q13.3
