Genetics Flashcards
What are some common facial features of turners syndrome?d
Low hairline, Webbed neck, small mandible, high arched palate and low set ears
How might an adolescent with turners syndrome present ?
Short stature, minimal breast development and primary amenorrhea
What cardiac abnormality is associated with turners syndrome?
Bicuspid aortic valve or coarctation
What are the chances of turners syndrome in a woman with advanced age?
The same as the normal palpitation! A chromosome deletion is not associated with advanced maternal age (only trisomys are increased)
How do you diagnose turners and what test is inadequate ?
Need karyotype - if mosaicism, karyotype may be normal but FISH can detect mosaicism
Buccal smear inaccurate
What is the genetic defect in cri du chat?
Deletion of the short arm of chromosome 5
What is the difference between apert syndrome and crouzon syndrome?
Both have craniosynostosis but only apert presents with syndactyly
What features of noonan syndrome differentiate from Turner syndrome?
Noonan syndrome has pectus excavatum and pulmonic stenosis
Karyotype is normal!!
What is the inheritance of crouzon syndrome?
Autosomal dominant
A child presents with craniosynostosis, prominent forehead, proptosis and a beak nose, what syndrome should you consider?
Crouzon syndrome
You are presented with a tall male with small testes who is socially awkward, what should you test for?
Klinefelters - chromosome analysis
Which age group gives birth to the most amount of trisomies?
Women in their 20s
What is the most common abnormality in children with Down syndrome?
Hypotonia
If a mother has a full translocation of chromosome 21, what are the chances her child will have Down syndrome?
100%
If a child has trisomy without translocation of chromosome 21, what are the chances the mother will have another chicks with Down syndrome?
1% plus the age related risk
If an infant had a partial translocation of chromosome 21, what are the chances of recurrence based on which parent the defect came from?
The partial translocation has a higher chance of recurrence if it is from the father
What is the age related risk of trisomy 21 in a 22 year old mother?
1/1500
What is the age related risk of developing Down syndrome in a child born to a 40y/o mother?
1/90
Children with Down syndrome are at increased risk for what 4 conditions?
Leukemia
Duodenal atresia
Endocardial cushion defects
Atlantoaxial instability
What are the signs/symptoms of trisomy 13?
"BAD LUCK" Brain lesions (microcephaly / holoprosencrphaly) Abnormally low ears Digits (polydactyly) Leukocyte with nuclear projections Uterus bicornuate or hypoplastic ovaries Cleft lip/palate Kidneys (cystic)
What abnormalities exist in the extremities of a patient with Down syndrome?
5th digit dysplasia
Simian crease
Hyperextensible joints
Wide gap between 1st and 2nd toe
What syndrome would you consider in a patient with atrial septal defect and upper limb defects including three jointed thumbs?
Holt Oram syndrome
What syndrome should you consider in a child with self mutilation and choreiform movements?
Lesch nyhan syndrome
What lab abnormalities would you find in a child with lesch nyhan?
Elevated uric acid
A patient presents with rocker bottom feet and clenched fists, what syndrome should you consider?
Trisomy 18
What abnormal facial features would you find in trisomy 18?
Prominent occiput and low set ears
What organs might be found to be abnormal in a child with trisomy 18?
Horseshoe kidneys
What syndrome should you consider in a child with cafe au lait spots, fibrous dysplasia and precocious puberty?
Mccune Albright syndrome
What two syndromes show genetic imprinting and how?
Angelman - chromosome 15 (deletion from mom and 2 copies from dad)
Prader Willi - chromosome 15 (deletion from dad and 2 copies from mom)
What syndrome should you consider in a patient severe developmental delay, movement disorders and excessive laughing?
Angelman syndrome
What syndrome should you consider in a patient who is obese with small hands and testicles?
Prader Willi
What autosomal recessive disorder is characterized by progressive CNS, oohthalmologic and endocrine problems?
Laurence moon syndrome
What are the similarities and differences between Prader Willi and Laurence moon syndrome ?
Both have obesity and hypogonadism but only Laurence moon causes syndactyly and retinal dystrophy
What syndrome is associated with omphalocele, Macroglossia, hypospadias, hypoglycemia and hemihypertrophy?
Beckwith wiedemann
How do you test for digeorge syndrome?
Chromosomal analysis won’t detect the micro deletion - need FiSH study
If mother is a carrier if an X linked recessive disorder, what are the chances she will have an affected child?
25% will have disease
25% will be carriers
What are the chances that a mother who is a carrier of an x linked recessive disorder will have an affected male child?
50% will be affected
Can a female be affected by an X linked recessive disorder?
No! They can only be carriers!
What type of inheritance is androgen insensitivity?
X linked recessive
What type of inheritance is wiskott Aldrich?
X linked recessive
What type if inheritance is retinitis pigmentosa?
X linked recessive
What type of inheritance is nephrogenic diabetes insipidus?
X linked recessive
What type if inheritance is duchenne muscular dystrophy ?
X linked recessive
What type of inheritance is chronic granulomatous disease?
X linked recessive
What type of inheritance is hemophilia?
X linked recessive
What type of inheritance is G6PD deficiency ?
X linked recessive
What is the only x linked recessive disorder that can be found in a female?
Androgen insensitivity - patient is phenotypically female but is genetically XY
What are the 4 X linked dominant disorders?
X linked hypophospatemic rickets
Pseudohyperparathyroidism
Acardi syndrome
Alport syndrome
In what syndrome do patients present with macrocephaly, ocular abnormalities and absent corpus callosum?
Aicardi syndrome
What type of inheritance is peutz jeghers syndrome?
Autosomal dominant disorder
What type of inheritance is Von willebrand disease?
Autosomal dominant disorder
What type of inheritance is Huntington chorea?
Autosomal dominant disorder
What type of inheritance is waardenburg syndrome?
Autosomal dominant disorder
What type of inheritance is Gardner syndrome?
Autosomal dominant disorder
What type of inheritance is Marfan syndrome ?
Autosomal dominant disorder
What type of inheritance is neurofibromatosis?
Autosomal dominant disorder
What type of inheritance is retinoblastoma?
Autosomal dominant disorder
What type of inheritance is achondroplasia ?
Autosomal dominant disorder
What type of inheritance is tuberous sclerosis?
Autosomal dominant disorder
What type of inheritance are the porphyrias?
Autosomal dominant disorder
What type of inheritance is galactosemia?
Autosomal recessive
What type if inheritance is alpha 1 anti trypsin deficiency ?
Autosomal recessive
What type if inheritance is sickle cell disease and thalassemia?
Autosomal recessive
What type of inheritance are hurlers and Tay Sachs disease?
Autosomal recessive
What type of inheritance is ataxia telangiectasia?
Autosomal recessive
What type of inheritance is Wilson disease?
Autosomal recessive
What type of inheritance is PKU?
Autosomal recessive
What type of inheritance is kartagener syndrome ?
Autosomal recessive
When can chorionic villus sampling be performed?
12 weeks
When can amniocentesis be performed?
16 weeks
What is the best test in predicting fetal lung maturity? Why?
When is this test NOT accurate?
Phosphatidylglycerol - absent prior to 35 weeks gestation
Not reliable if diabetes - need total surfactant activity
What are the common findings in fetal alcohol syndrome ?
Short philtrum, thin upper lip, facial hypoplasia, short palpebral fissure and small 5th fingernail
What symptoms are associated with teratogenic exposure to anticonvulsants?
Microcephaly IUGR Cardiac defect Cleft lip Hypospadias Cryptorchidism Club foot Cardiac defect
What effects can lithium have on the developing fetus?
Ebsteins anomaly
What 5 things can occur to a fetus when mother is taking isotretinoin?
Microcephaly Micropthalmia Hypoplastic ears Truncus arteriosis Absent thymus
What specific defects are associated with carbamazepine during pregnancy ?
Spina bifida
Facial deformities
What specific defects are seen with phenytoin in pregnancy?
Finger stiffness Nail hypoplasia Cardiac anomalies skeletal anomalies Ophthalmology anomalies
What specific defects are associated with valproic acid during pregnancy?
Neural tube defects
What anatomical defects are associated with warfarin use during pregnancy?
Depressed nasal bridge
Hypoplastic distal phalanges
Stippled epiphyses
What fetal defects are found with ace inhibitor use during pregnancy?
Anuria
Oligohydramnios
Skull hypoplasia
Fetal hypotension
What is the charge association?
Coloboma & cognitive defects Heart disease Atresia choanal Retarded growth GU abnormalities Ear anomalies
What is associated with the VACTERL syndrome?
Vertebral defects Anal atresia Cardiac defects (VSD) TE fistula Renal defects Limb abnormalities
What is potter syndrome?
Oligohydramnios sequence = hypoplastic lungs, limb malformations (club feet, excess skin on hands), renal agenesis and IUGR
In what condition might the fetal membranes be covered in yellow nodules (amnion nodosum)?
Oligohydramnios (potter) sequence
In what syndrome do patients present with a broad thumb and cryptorchidism?
Rubinstein taybi syndrome
In what syndrome do patients present with broad thumbs and wide spaces eyes?
Pfeiffer syndrome
In what syndrome do patients present with a small chin and growth retardation?
Russell silver syndrome