The Question is from neet-botany biotechnology medicine, and it was created by the author Mr. NARESH KUMAR K

Question

A 30-year-old female presents with recurrent episodes of severe abdominal pain, vomiting, and peripheral neuropathy.  Urine porphyrin levels are elevated.  Which enzyme deficiency is MOST likely responsible for her condition?

Mr. NARESH KUMAR K · Accepted Answer

## CORE INFORMATION
✓ **Answer**: B
## CONCEPT FRAMEWORK
 **Primary Concept**: Porphyria
 **Related Topics**: Enzyme deficiencies, heme synthesis pathway, porphyrin metabolism
 **Prerequisites**: Understanding of the heme synthesis pathway and the roles of different enzymes involved.
## SOLUTION PATHWAY
**Given Information**:
  * 30-year-old female patient
  * Recurrent episodes of severe abdominal pain, vomiting, and peripheral neuropathy
  * Elevated urine porphyrin levels
**Method & Steps**:
 1. Identify the pathway affected: The symptoms (abdominal pain, vomiting, neuropathy, and elevated urine porphyrins) strongly suggest a porphyria, a group of disorders resulting from defects in the heme biosynthesis pathway.
  Reasoning: Porphyrias are characterized by the accumulation of porphyrin precursors in erythrocytes, body fluids, and tissues, leading to a variety of clinical manifestations.
  Formula/Rule:  None directly applicable, but understanding the heme synthesis pathway is crucial.
 2. Analyze the enzyme options and their roles in heme synthesis:
  Working: The heme synthesis pathway involves several enzymes.  Uroporphyrinogen decarboxylase (UROD) catalyzes the decarboxylation of uroporphyrinogen to coproporphyrinogen.  Deficiency in UROD leads to the accumulation of uroporphyrinogen and its precursors in the urine, causing porphyria cutanea tarda (PCT).
  Key Point:  The clinical presentation (abdominal pain, neuropathy, elevated urine porphyrins) is consistent with PCT.
 3. Determine the most likely enzyme deficiency:
  Result: Uroporphyrinogen decarboxylase deficiency is the most likely cause of the patient's condition.
  Verification:  The symptoms and elevated urine porphyrins align with the characteristic features of porphyria cutanea tarda, which is caused by UROD deficiency.
 ## OPTION ANALYSIS
A :x: Aminolevulinic acid dehydratase deficiency causes acute intermittent porphyria, which typically presents with acute attacks of abdominal pain, neurological symptoms, and elevated δ-aminolevulinic acid (ALA) and porphobilinogen (PBG) in the urine, but not necessarily with significant peripheral neuropathy.
B ✓: Uroporphyrinogen decarboxylase deficiency is the most common cause of porphyria cutanea tarda, which frequently presents with photosensitivity, skin lesions, and abdominal pain.  Neurological symptoms can occur, but are less prominent than in acute intermittent porphyria.
 C :x: Porphobilinogen deaminase deficiency causes acute intermittent porphyria (AIP), characterized by acute attacks of abdominal pain, neurological symptoms (including peripheral neuropathy), and elevated porphobilinogen in the urine.
D :x: Ferrochelatase deficiency causes erythropoietic protoporphyria, which primarily involves photosensitivity, skin lesions, and anemia, not the specific symptoms presented in the question.
 ## LEARNING AIDS
 **Common Mistakes**:
  1.Confusing the different types of porphyrias and their associated enzyme deficiencies:  Understanding the specific symptoms and porphyrin profiles associated with each type is crucial for accurate diagnosis.
  2.Overlooking the importance of the clinical presentation: The combination of abdominal pain, neuropathy, and elevated urine porphyrins is key to directing the diagnosis toward a specific type of porphyria.
 **Quick Tips**:
  1.Remember the key enzymes in heme synthesis and their associated porphyrias: ALA dehydratase (AIP), PBG deaminase (AIP), UROD (PCT), Ferrochelatase (EPP).
  2.Use a mnemonic device or flowchart to organize the different porphyrias and their clinical features.

Mr. NARESH KUMAR K · Answer

Aminolevulinic acid dehydratase

Mr. NARESH KUMAR K · Answer

The correct Option is "Uroporphyrinogen decarboxylase"

Mr. NARESH KUMAR K · Answer

Porphobilinogen deaminase

Mr. NARESH KUMAR K · Answer

Ferrochelatase

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