Скачать или смотреть 🧬 Dubin-Johnson Syndrome | USMLE Step 1 Biochemistry | Dr G Bhanu Prakash

📌𝗝𝗼𝗶𝗻 𝗢𝘂𝗿 𝗧𝗲𝗹𝗲𝗴𝗿𝗮𝗺 𝗖𝗵𝗮𝗻𝗻𝗲𝗹 𝗛𝗲𝗿𝗲:- https://t.me/bhanuprakashdr
📌 𝐅𝐨𝐥𝐥𝐨𝐰 𝐨𝐧 𝐈𝐧𝐬𝐭𝐚𝐠𝐫𝐚𝐦:-   / drgbhanuprakash  
📌𝗦𝘂𝗯𝘀𝗰𝗿𝗶𝗯𝗲 𝗧𝗼 𝗠𝘆 𝗠𝗮𝗶𝗹𝗶𝗻𝗴 𝗟𝗶𝘀𝘁:- https://linktr.ee/DrGBhanuprakash

🧬 Dubin-Johnson Syndrome | USMLE Step 1 Biochemistry | Dr G Bhanu Prakash

Dubin-Johnson syndrome (DJS) is a rare, benign autosomal recessive disorder characterized by chronic, mild conjugated (direct) hyperbilirubinemia due to a defect in hepatic excretion of conjugated bilirubin into the bile canaliculi. It is a high-yield biochemistry topic for USMLE Step 1, particularly in the context of bilirubin metabolism, and is often tested alongside Rotor syndrome, though they have distinct pathophysiologic and histologic features.

The biochemical basis of DJS lies in mutations affecting the MRP2 (multidrug resistance–associated protein 2) transporter, which is responsible for secreting conjugated bilirubin into bile. As a result, conjugated bilirubin accumulates in hepatocytes and leaks back into circulation, leading to elevated direct bilirubin levels in the serum. However, liver function tests (AST, ALT, ALP) and synthetic function (albumin, INR) remain normal.

Clinically, Dubin-Johnson syndrome typically presents in adolescence or early adulthood with intermittent jaundice, especially during stress, illness, pregnancy, or oral contraceptive use. Importantly, the condition is asymptomatic aside from jaundice and does not progress to liver failure.

A distinguishing histological hallmark is the presence of a grossly black liver due to accumulation of epinephrine metabolites in lysosomes—making this a classic image-based question on exams. In contrast to Rotor syndrome, urinary coproporphyrin excretion in DJS is normal in amount, but the ratio is altered, with increased coproporphyrin I.

Key features for USMLE Step 1:
--------------------------------------------------
Conjugated (direct) hyperbilirubinemia
Defective MRP2 transporter
Black liver on gross pathology
Benign course, no treatment needed
Normal liver enzymes and function
Altered coproporphyrin I/III ratio in urine

No treatment is required, and prognosis is excellent. Recognition of Dubin-Johnson syndrome is important to avoid unnecessary investigations or treatment in a patient with isolated jaundice and normal liver function.

#DubinJohnsonSyndrome #MRP2Defect #ConjugatedHyperbilirubinemia #BlackLiver #USMLEStep1 #BiochemistryBuzzwords #DrGBhanuPrakash #RotorVsDubinJohnson #LiverTransporters #AutosomalRecessive #MedicalEducation #WhiteboardBiochemistry #MCQPrep #USMLEBuzzwords #BilirubinMetabolism #GrossPathology #Step1Review #HighYieldBiochem #BenignJaundice #PigmentAccumulation #HepaticExcretionDefect #USMLE2025 #medicalanimations #fmge #fmgevideos #rapidrevisionfmge #fmge2024 #mbbslectures #nationalexitexam #nationalexittest #neetpg #usmlepreparation #usmlestep1 #fmge #usmle #drgbhanuprakash #medicalstudents #medicalstudent #medicalcollege #neetpg2025 #usmleprep #usmlevideos #usmlestep1videos #medicalstudents #neetpgvideos #usmlestep2videos