WBR0312

Author	PageAuthor::William J Gibson
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Genetics
Sub Category	SubCategory::Reproductive, SubCategory::General Principles
Prompt	[[Prompt::A newborn female is born via cesarean section to a 42 year old primigravid woman. The child has microcephaly with a prominent occiput, low-set ears, cleft palate and “rocker bottom” feet with webbed toes. An image of the patient’s hands is shown below. What is the life expectancy of this child? ]]
Answer A	AnswerA::60 years
Answer A Explanation	AnswerAExp::'''Incorrect:''' This is the life expectancy of Down Syndrome patients. However, many Down syndrome patients begin to be affected by Alzheimer’s disease between the ages of 40 and 50.
Answer B	AnswerB::10-15 years
Answer B Explanation	AnswerBExp::'''Incorrect:''' This is the life expectancy of patients with progerioid syndromes such as Hutchinson-Gilford progeria.
Answer C	AnswerC::1 year
Answer C Explanation	AnswerCExp::'''Incorrect:''' This is the life expectancy of Patau syndrome patients. Patau syndrome is caused by an extra copy of chromosome 13.
Answer D	AnswerD::1 week
Answer D Explanation	AnswerDExp::'''Correct:''' The life expectancy of Edwards syndrome patients is around 1 week if they survive to birth.
Answer E	AnswerE::1 day
Answer E Explanation	AnswerEExp::'''Incorrect:''' This life expectancy is too short for Edward’s Syndrome. The life expectancy of anencephaly is on the order of one day.
Right Answer	RightAnswer::D
Explanation	[[Explanation::The patient in this vignette has Edward’s syndrome. Edward’s syndrome is a chromosomal abnormality caused by the presence of all or part of an extra 18th chromosome. Around 80 percent of Edwards syndrome patients are female. The majority of fetuses with the syndrome die before birth; those who survive have a median life expectancy of around 1 week. The physical characteristics of Edwards Syndrome include the following: clenched fingers small jaw small head prominent back portion of the skull (occiput) low-set, malformed ears cleft lip / palate webbing of the toes “rocker bottom” feet Educational Objective: Edwards syndrome is a chromosomal abnormality of chromosome 18 with severe symptoms; the life expectancy of live births is around one week. References: First Aid 2012 page 93 Educational Objective: References: ]]
Approved	Approved::Yes
Keyword	WBRKeyword::Edward's Syndrome, WBRKeyword::Chromosome, WBRKeyword::Chromosomal Abnormality, WBRKeyword::Aneuploidy, WBRKeyword::Newborn
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::