An 18-month-old girl is brought to the pediatrician’s office for failure to thrive and developmental delay. The patient’s mother says she has not started speaking and is just now starting to pull herself up to standing position. Furthermore, her movement appears to be restricted. Physical examination reveals coarse facial features and restricted joint mobility. Laboratory studies show increased plasma levels of several enzymes. Which of the following is the underlying biochemical defect in this patient?
ACongenital lack of lysosomal formation
BInappropriate protein targeting to endoplasmic reticulum
CFailure of mannose phosphorylation
DInappropriate degradation of lysosomal enzymes
EMisfolding of nuclear proteins
A 21-year-old female presents to her obstetrician because she has stopped getting her period, after being irregular for the last 3 months. Upon further questioning, the patient reveals that she has had a 17 lb. unintended weight loss, endorses chronic diarrhea, abdominal pain, and constipation that waxes and wanes. Family history is notable only for an older brother with Type 1 Diabetes. She is healthy, and is eager to gain back some weight. Her OBGYN refers her to a gastroenterologist, but first sends serology laboratory studies for IgA anti-tissue transglutaminase antibodies (IgA-tTG). These results come back positive at > 10x the upper limit of normal. Which of the following is the gastroenterologist likely to find on endoscopy and duodenal biopsy?
AFriable mucosal pseudopolyps with biopsy notable for crypt abscesses
BCobblestoning with biopsy showing transmural inflammation and noncaseating granulomas
CVillous atrophy with crypt lengthening and intraepithelial lymphocytes
DFoamy macrophages, which stain PAS positive
ENormal appearing villi and biopsy
An 8-month-old boy is brought to the physician by his parents for gradually increasing loss of neck control and inability to roll over for the past 2 months. During this time, he has had multiple episodes of unresponsiveness with a blank stare and fluttering of the eyelids. His parents state that he sometimes does not turn when called but gets startled by loud noises. He does not maintain eye contact. He was able to roll over from front to back at 5 months of age and has not yet begun to sit or crawl. His parents are of Ashkenazi Jewish descent. Neurological examination shows generalized hypotonia. Deep tendon reflexes are 3+ bilaterally. Plantar reflex shows extensor response bilaterally. Fundoscopy shows bright red macular spots bilaterally. The remainder of the examination shows no abnormalities. Which of the following is the most likely cause of this patient's symptoms?
ASphingomyelinase deficiency
Bβ-glucocerebrosidase deficiency
Cα-galactosidase A deficiency
DATP-binding cassette transporter mutation
Eβ-hexosaminidase A deficiency
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