Genetic diseases Flashcards
Trisomy 13 is also called?
Patau syndrome
Basic mechanism of Patau?
Nondisjunction, Translation, or Mosaicism
Clinical features of Trisomy 13?
Cleft lip/palate, polydactyly, holoproencephaly
Diagnosis for Trisomy 13?
Karyotype
Genetic counseling for Trisomy 13
Prenatal diagnosis, recurrence risk, maternal age
Basic mechanisms of Trisomy 18
Nondisjunction, translocation, or mosaicism
Another name for Trisomy 18
Edwards
Clinical features of Trisomy 18
Clenched hand, micrognathia
Diagnosis for Trisomy 18?
Karyotype
Genetic counseling for Tisomy 18?
Prenatal diagnosis, recurrence risk, maternal age
Trisomy 21 is also known as?
Down Syndrome
Basic mechanism of Trisomy 21?
Nondisjunction, translocation (Robersonian), or mosaicism
Key features of Trisomy 21
Congenital heart disease, single palmar crease, slanted eye fissures, flat facies
Diagnosis of Trisomy 21
Karyotype
Genetic counseling for Trisomy 21
Prenatal diagnosis-increased nuchal lucency (US scan of fluid at neck in fetus), recurrence risk, maternal age
Genotype for Turner syndrome
45X
Basic mechanism for Turner syndrome?
Nondisjunction, X structural abnormality, or mosaicism
Clinical features of Turner syndrome
Short female, broad chest, congenital lymphadema
Diagnosis of Turner syndrome
Karyotype
Genetic counseling for Turner syndrome
Prenatal diagnosis - cystic hygroma (lympohcytic malformation/mass typically in neck), fetal hydrops (fluid accumulation in at least two compartments of fetus)
Klinefelter syndrome genotype?
47,XXY
Mechanism for Klinefelter?
Chromosomal nondisjunction or mosaicism
Clinical features of Klinefelter?
Hypogonadism/testicular atrophy, infertility
Diagnosis of Klinefelter?
Karyotype
Genetic counseling for Klinefelter?
Recurrence risk - Not increased
Cri du chat is also known as?
5p deletion
Mechanism for Cri du chat?
De novo or familial chromosome 5 abnormality
Clinical features of Cri du chat?
Cat like cry, microencephaly, mental retardation
Diagnosis of Cri du chat?
Karyotype or array-CGH (gains or losses of chromosomes or regions of chromosomes)
Counseling for Cri du chat?
Recurrence risk - depends on familial vs de novo
Two other names for 22q11 deletion syndrome
DiGeorge syndrome
Velocardial-facial syndrome
Mechanism of DiGeorge?
22q11 microdelection
Autosomal dominant, de novo, or familial
Clinical features of DiGeorge
Neonatal hypocalcemia, congenital heart defects, thymic hypoplasia
Diagnosis of DiGeorge
FISH for 22q11, array CGH
Array CGH measures for?
Gains or loses of chromosomes or regions of chromsomes
Genetic counseling for DiGeorge
Recurrent risk depends on familial vs de novo
Mechanism of Williams syndrome
7q11 microdeletion
Autosomal dominant, de novo, or familial
Clinical features of Williams syndrome
Friendly personality, supravalvular aortic stenosis, hypercalcemia
Diagnosis for Williams syndrome
FISH for 7q11, array CGH
Genetic counseling for Williams syndrome
Recurrence risk depends on familial vs de novo
Mechanism of Prader-Willi syndrome
Paternal deletion of 15q11-q13
Maternal uniparental disomy 15 or imprinting defect
Clinical features of Prader-Willi
Infantile hypotonia, obesity, mental retardation
Diagnosis of Prader-Willi
DNA methylation
Recurrence risk of Prader-Willi
Recurrence risk depends on genetic mechanism
Angelman syndrome mechanism?
Maternal deletion for 15q11-q13, paternal uniparental disomy, or imprinting defect
Clinical features of Angelman
Microcephaly, absent speech, ataxia
Diagnosis of Angelman
DNA methylation
Genetic counseling for Angelman
Recurrence risk depends on genetic mechanism
Mechanism of Rett syndrome
X linked dominant
Lethal in male
Clinical features of Rett syndrome
Mental retardation with girl
Hand wringing
Lethal in males
Diagnosis of Rett syndrome
DNA studies
Genetic counseling of Rett syndrome
X linked
Recurrence risk - most de novo/simplex
Mechanism of fragile X syndrome
X linked
Trinucleotide repeat CGG premutation expansion
Clinical features of Fragile X syndrome
Mental retardation in males and females
Large ears
Macro-orchidism
Diagnosis of Fragile X syndrome
DNA studies for size of repeat
Genetic counseling for Fragile X syndrome
X linked
Recurrence risk depends on allele size
Hemophilia A is deficiency in what factor?
Factor VIII
Mechanism of Hemophilia A?
X linked recessive
Clinical features of Hemophilia A?
Bleeding disorder
Diagnosis of Hemophilia A
Low factor activity of VIII
Normal vWF factor level
DNA testing
Hemophilia B is known as?
Christmas disease
Factor IX deficiency
Mechanism of Hemophilia B
X linked recessive
Clinical features of Hemophilia B
Bleeding disorder
Diagnosis of Hemophilia B
Low factor IX clotting activity
DNA testing
Genetic counseling of Hemophilia B
X linked
Genetic counseling of Hemophilia A
X linked
Mechanism of achondroplasia
Autosomal dominant
Clinical features of achondroplasia
Short limbs
Dwarfism
Large head
Diagnosis of Achondroplasia
Clinical features and Xray findings
Genetic counseling of achondroplasia
Autosomal dominant
Paternal age
Autosomal-dominant polycystic kidney disease (adult)
Autosomal dominant (versus ARPKD-infantile)
Clinical features of ADPKD
Bilateral kidney cystes
Diagnosis of ADPKD
Imaging studies of kidneys
Genetic counseling of ADPKD
Autosomal dominant
Ehlers-Danlos syndrome, classic mechanism?
Autosomal dominant
Connective tissue disorder (Type V collagen)
Clinical features of Ehlers-Danlos
Skin hyperextensibility
Abnormal wound healing
Joint hypermobility
Diagnosis of Ehler-Danlos syndrome
Skin hyperextensibility
Abnormal wound healing
Joint hypermobility
Genetic counseling for Ehler-Danlos syndrome
Autosomal dominant
Mechanism of Marfan syndrome
Autosomal dominant
Connective tissue disorder (fibrillin)
Clinical feature of Marfan
Tall with long arms
Arachnodactyly (spider fingers)
Aortic aneurysm
Diagnosis of Marfan
Tall with long arms
Arachnodactyly (spider fingers)
Aortic aneurysm
Genetic counseling of Marfan
Autosomal dominant
Mechanism of Neurofibromatosis Type 1
Autosomal dominant
Neurocutaneous syndrome
Neurofibromatosis Type 1 is also called?
Recklinghausen’s disease
Clinical features of Neurofibromatosis Type 1
Cafe-au-lait spots
Axillary/inguinal freckling
Lisch nodules (spots on the iris)
Neurofibromas (nerve sheath tumors)
Diagnosis of Neurofibromatosis Type 1
Cafe-au-lait spots
Axillary/inguinal freckling
Lisch nodules (spots on the iris)
Neurofibromas (nerve sheath tumors)
Mechanism of cystic fibrosis
Autosomal Recessive
Mutation of CFTR chloride channel
Clinical features of cystic fibrosis
Lung and GI disease
Diagnosis of cystic fibrosis
Lung and GI disease
Sweat chloride testing
DNA testing
Genetic counseling for cystic fibrosis
autosomal recessive
Carrier testing
Neural tube defect clinical features
Brain and spinal cord birth defects
Spinal bifida and anencephaly
Diagnosis of neural tube defects
Clinical fetal ultrasound
Maternal amnio-elevated AFP (alpha-fetal protein)
Genetic counseling of neural tube defects
Prenatal diagnosis
