Genotype-Phenotype Association in ABCC2 Exon 18 Missense Mutation Leading to Dubin-Johnson Syndrome: A Case Report

We report a case of a patient with Dubin-Johnson syndrome confirmed by a genetic study. A 50-year-old woman who had symptoms of intermittent right upper quadrant abdominal pain was diagnosed with calculous cholecystitis at another institute and was presented to our hospital for a cholecystectomy. She had no history of liver disease, and her physical examination was normal. Abdominal computed tomography showed a gallbladder stone with chronic cholecystitis. During a laparoscopic cholecystectomy for cholecystitis, a smooth, black-colored liver was noted, and a liver biopsy was performed. The biopsy specimen showed coarse, dark brown granules in centrilobular hepatocytes via hematoxylin and eosin staining. We performed a genetic study using the blood samples of the patient. In the adenosine triphosphate-binding cassette subfamily C member 2 (ABCC2) mutation study, a missense mutation in exon 18 was noted. Based on the black-colored liver without nodularity, conjugated hyperbilirubinemia, the liver biopsy results of the coarse pigment in centrilobular hepatocytes, and the ABCC2 mutation, Dubin-Johnson syndrome was diagnosed. The patient was managed with conservative care using hepatotonics. One month after follow-up, total bilirubin and direct bilirubin remained in a similar range. Another follow-up was planned a month later, and the patient maintained her use of hepatotonics.

[Genetic analysis of a case with Dubin-Johnson syndrome due to two novel variants of ABCC2 gene]

OBJECTIVE

To explore the genetic etiology and differential diagnosis for a patient with jaundice.

METHODS

Clinical data of the patient and his parents were collected. Genes associated with metabolic liver diseases were subjected to high-throughput sequencing. The pathogenicity of the candidate variants was predicted by using bioinformatics software.

RESULTS

High-throughput sequencing revealed that the proband has harbored two variants of the ABCC2 gene (NM_000392) including c.3011C>T (p.T1004I) and c.3541C>T (p.R1181X), which were respectively inherited from his father and mother. Both variants have been previously unreported and predicted to be pathogenic by bioinformatics analysis.

CONCLUSION

The proband was diagnosed with Dubin-Johnson syndrome due to the compound heterozygous variants of the ABCC2 gene. Genetic testing has enabled accurate differential diagnosis of Dubin-Johnson syndrome in this patient.

A case of true vocal fold jaundice

OBJECTIVES

While jaundice is frequently described in the sclera and skin, there are few reports of true vocal fold jaundice in patients with high bilirubin, and no reports by otolaryngologists in the literature. Here we describe a case of a patient with bilateral true vocal fold jaundice and discuss the potential pathogenesis and implications of this finding.

METHODS

A 29-year-old man with history of Dubin-Johnson Syndrome presented with cough and difficulty breathing and was incidentally found to have persistent yellow discoloration of the true vocal folds bilaterally.

RESULTS

Videolaryngoscopic exam demonstrated bilateral true vocal fold yellow discoloration with sparing of nearby laryngeal structures on initial presentation and follow-up exam. Direct and total bilirubin levels were found to be elevated.

CONCLUSION

A patient with benign Dubin-Johnson Syndrome and elevated total and direct bilirubin was incidentally found to have bilateral vocal fold jaundice. Jaundice and the presence of bilirubin do not appear to cause harm to the function or health of the true vocal folds and may be related to the high concentration of elastin present in the true vocal folds.

Role of Multidrug-Resistance Protein 2 in coproporphyrin transport: results from experimental studies in bile fistula rat models

Coproporphyrin (CP) is one of the main by-products of heme biosynthesis and its abnormal accumulation is associated with different forms of porphyria. Indirect data obtained from animal and human models have suggested a possible role for Multidrug Resistance-associated Protein 2 (MRP2) and other MRPs in hepatocyte excretion of CP. Using normal, MRP2-deficient and a cholestatic rat model, we have assessed the role of MRPs in CP disposition. MRP levels were assayed using immunofluorescence. Biliary and urinary excretion patterns of CP and conjugate bilirubin were measured during equimolar infusions of CP isomers with and without phenoldibromopthalein sulfonate (BSP), a well-known MRP2 substrate. Our results suggest a role for the MRP system as a possible regulator of CP traffic and accumulation in normal and pathological conditions. Alteration in this systems (as observed in cholestatic disease) may play an important role in triggering clinical expression of porphyria in individuals with underlying mutations leading to porphyrin accumulation and may help explain the phenotypic heterogeneity in patients affected by different forms of porphyrias.

Dubin-Johnson syndrome with systemic lupus erythematosus: a case report

BACKGROUND

Dubin-Johnson syndrome (DJS) is a rare clinical entity. We describe a case of DJS complicated by systemic lupus erythematosus (SLE).

METHODS

A case of congenital hyperbilirubinemia with SLE was evaluated systematically including review of history, physical examination for the stigmata of chronic liver disease, and other investigations.

RESULT

Liver biopsy revealed a black liver with preserved architecture suggestive of DJS.

CONCLUSIONS

SLE may develop in DJS. The relationship between DJS and SLE in this case is most likely a chance occurrence.

Dubin-Johnson syndrome--a clinicopathologic study of twenty cases

Dubin-Johnson syndrome (DJS) is a rare benign chronic disorder of bilirubin metabolism, characterized by conjugated hyperbilirubinemia, darkly pigmented liver and presence of abnormal pigment in hepatic parenchymal cells. This is a retrospective study of twenty cases of DJS highlighting their major clinical and pathological findings. Liver biopsies were available in all the cases, obtained during a fourteen-year period (January 1991 to March 2005). The patients' age ranged from 7-63 years (median 21 years). These twenty cases comprised 13 males and 7 females. Major clinical manifestations were recurrent or persistent jaundice, abdominal pain and fever. Duration of illness ranged from 9 months to 58 years (median 10 years). All of them had conjugated hyberbilirubinemia and total serum bilirubin levels ranged between 1.4-13 mg/dl (mean 4.4 mg/dl). Liver biopsies revealed presence of coarse granular brown pigment in the cytoplasm of hepatocytes more concentrated in the pericanalicular region and more prominent in centrilobular hepatocytes. Associated findings were presence of hepatitis B virus related chronic hepatitis (1), history of tubercular lymphadenitis (1), chronic cholecystitis in (2), coronary heart disease (1) and exacerbation during pregnancy (1).

Ultrastructure of Kupffer cells and hepatocytes in the Dubin-Johnson syndrome: A case report

Ultrastructure of Kupffer cells and hepatocytes in liver bioptate was evaluated in a 17-year-old boy with Dubin–Johnson syndrome (DJS). The liver tissue obtained by needle biopsy was fixed in glutaraldehyde and paraformaldehyde and routinely processed for electron microscopic analysis. The ultrastructural examinations of liver bioptate revealed the accumulation of membrane-bound, electron-dense lysosomal granules within the cytoplasm of hepatocytes, characteristic of DJS. They were located mainly in the vicinity of the biliary pole, and preferentially in the centrilobular region that corresponded to the pigment deposits seen under light microscope. The presence of the granules was accompanied by dilated elements of the granular endoplasmic reticulum and paracrystalline mitochondrial inclusions as well as dilation of the bile canaliculi. The changes in hepatocytes co-existed with marked stimulation and enhanced phagocytic activity of Kupffer cells. This was manifested in the accumulation of pigment deposits within their cytoplasm that corresponded to those observed in hepatocytes. Hyperactive pericentral Kupffer cells which are involved in the response to pigmentary material originating from disintegrated hepatocytes may play an essential role in the development of DJS.

Dual hereditary jaundice: simultaneous occurrence of mutations causing Gilbert's and Dubin-Johnson syndrome

BACKGROUND & AIMS

Dubin-Johnson syndrome is recessively inherited, conjugated hyperbilirubinemia induced by mutations in the ABCC2/MRP2 gene encoding the canalicular transporter for conjugated bilirubin. Gilbert's syndrome is recessively inherited, unconjugated hyperbilirubinemia caused by decreased conjugation rate of bilirubin associated mostly with homozygous A(TA) 7 TAA variant of the TATAA-box in the UGT1A1 gene promoter. Our aim was to establish the molecular diagnosis in a 3-year-old male with atypical, intermittent, predominantly unconjugated, hyperbilirubinemia.

METHODS

99m Tc-HIDA cholescintigraphy was used for imaging the biliary tree. Expression of ABCC2/MRP2 protein in hepatocytes was investigated immunohistochemically. UGT1A1 and ABCC2/MRP2 genes were sequenced from genomic DNA, and the mutations were verified by fragment analysis, sequencing the cloned exons, and restriction fragment length polymorphism.

RESULTS

Cholescintigraphy revealed delayed visualization of the gallbladder. A brown granular lipopigment differing from melanin-like pigment reported in Dubin-Johnson syndrome was present in hepatocytes, but, otherwise, liver histology was normal. ABCC2/MRP2 protein was not detected on the canalicular membrane of hepatocytes, and 2 novel mutations were found in the ABCC2/MRP2 gene: a heterozygous in-frame insertion-deletion mutation 1256insCT/delAAACAGTGAACCTGATG in exon 10 inherited from the father and a heterozygous deletion 4292delCA in exon 30 inherited from the mother. In addition, the patient was homozygous for -3279T>G and A(TA) 7 TAA mutations in the UGT1A1 gene promoter.

CONCLUSIONS

Our patient represents a case of digenic mixed hyperbilirubinemia-a distinct type of constitutive jaundice resulting from coinherited defects in ABCC2/MRP2 and UGT1A1 genes.

Association of Dubin-Johnson syndrome and portal vein thrombosis

Dubin-Johnson syndrome is neither complicated by liver cell necrosis nor associated with portal hypertension. We report a 22-year-old man who had recurrent episodes of jaundice (conjugated hyperbilirubinemia) because of Dubin-Johnson syndrome and portal hypertension secondary to portal vein thrombosis. The relationship between Dubin-Johnson syndrome and portal vein thrombosis in this case is most likely a chance occurrence.

A new mutation of the ATP-binding cassette, sub-family C, member 2 (ABCC2) gene in a Japanese patient with Dubin-Johnson syndrome

Dubin-Johnson syndrome (DJS) is an inherited disorder characterized by conjugated hyperbilirubinemia and is caused by mutations of the canalicular multispecific organic anion transporter (cMOAT)/ multidrug resistance protein 2 (MRP2)/ ATP-binding cassette, sub-family C, member 2 (ABCC2) gene. The ABCC2 protein is located in the apical membrane of hepatocytes, and known mutations of this gene cause impaired maturation and trafficking of the mutated protein from the endoplasmic reticulum (ER) to the Golgi complex. We have characterized the ABCC2 gene in a Japanese DJS patient by polymerase chain reaction and DNA sequencing, resulting in the identification of two mutations. One mutation, 1815+2 (T>A) in the splice donor site of intron 13, has already been reported. However, we have identified a novel nonsense mutation consisting of a (C>T) transition at nucleotide 3928 in exon 28.

Multiple black hepatocellular adenomas in a male patient

A 65-year-old man presented with multiple liver tumours. Imaging techniques could not differentiate between adenomas and hepatocellular carcinomas. He had no relevant past medical history. Liver function tests were normal except for a 1.5-fold rise in GGT. AFP was normal. Viral markers were negative. During laparoscopy, numerous black tumours of different sizes were seen. These tumours were adenomas without malignant transformation. Tumoral hepatocytes contained a brown pigment in the canalicular area without evidence of cholestasis. This pigment was Fontana positive and looked like Dubin-Johnson pigment by electron microscopy. The expression of the canalicular multispecific organic anion transporter (cMOAT) was decreased in the tumours but normal in the non-tumoral liver ruling out the diagnosis of Dubin-Johnson syndrome. There was mild iron deposition possibly related to an homozygous H63D mutation in the HFE gene. Three years after their discovery, the size of the tumours remained stable. It is concluded that this male patient with multiple adenomas and mild iron overload is at risk of developing an hepatocellular carcinoma and that the black colour of adenomas is probably due to a partial defect in excretion of organic anions.

Pigmented liver cell adenoma in two male patients

We report two cases of hepatocyte neoplasia with extensive deposition of Dubin-Johnson-like pigment in men without Dubin-Johnson syndrome. This pigment has previously been described in hepatocellular carcinoma but not in liver cell adenoma. The tumors of both patients showed some atypical cytologic features, but no frank histologic evidence of malignancy. Long-term follow up for several years showed no evidence of recurrence after limited surgical excision. We conclude that tumors with this structure may be cured by limited surgical excision and should be considered as pigmented liver cell adenomas.

[Clinical pathology of Dubin-Johnson syndrome]

OBJECTIVE

To investigate the property of pigment granules in the hepatocytes in patients with Dubin-Johnson syndrome.

METHOD

Light microscopy, histochemical, immnohistochemical and electron microscopy techniques were used to study the pigment glanules and the expression of S-100 protein and HMB45 in hepatocytes.

RESULTS

Histological examination revealed normal lobular architecture and the abundont brown pigments which were chiefly seen in the centrilobular zone hepatocytes. The pigment granules were evidenced to have the characterization of both lipofuscin and melanin by histochemical staining and ultrastructural studies and to have the featurts of the melanin by immnohistochemical staining.

CONCLUSION

The results suggest that the pigment graunles are lipfuscin-melanin complex in the hepatocytes in patients with Dubin-Johnson syndrome.

A case of late onset primary hyperoxaluria type I (PH-I) presented with black liver

A 63-year-old woman who had received hemodialysis therapy since she fell acute on chronic renal failure 4 years ago presented with multiple joint pain. Nephrocalcinosis was not detected by abdominal X-ray when hemodialysis therapy was initiated. Laboratory testing showed azotemia, anemia, hypoproteinemia and mild liver dysfunction but no liver cirrhosis. Biopsied bone tissue demonstrated numerous calcium oxalate crystal depositions. Laparoscopy revealed black liver in macroscopic view. Histological studies showed numerous lipofuscin-like dark brown granules were deposited in hepatocytes. The activity of alanine : glyoxylate aminotransferase (AGT) was less than 0.1 U/g in biopsied patient's liver tissue. Generally, clinical symptoms demonstrated by Japanese primary hyperoxaluria type I (PH-I) patients are milder than those of European patients. Some PH-I patients may successfully avoid urinary tract calcification unless they fall into oliguria by some other causes. The lipofuscin granules are most likely the source of the dark color. Massive deposition of the lipofuscin granules indicated that the duration of the liver metabolic abnormality had lasted for long time. Thus, black liver may be related to a mild form of PH-I.

Dubin-Johnson-like syndrome in golden lion tamarins (Leontopithecus rosalia rosalia)

On routine blood screens, persistent conjugated hyperbilirubinemia was discovered in two groups of closely related adult female golden lion tamarins (Leontopithecus rosalia rosalia, n = 8). Bromosulfophthalein (BSP) retention tests were performed on four hyperbilirubinemic and three control tamarins. BSP excretion was delayed in hyperbilirubinemic tamarins as compared with controls. Grossly, liver of affected tamarins was dark brown to black, with a prominent reticulated pattern. Histologic examination revealed abundant intrahepatic pigment, primarily in a centrilobular and midzonal distribution. Most of the pigment did not react with Perls' Prussian blue method for iron, Hall's method for bilirubin, or the Armed Forces Institute of Pathology acid-fast method for lipofuscin but was positive with Fontana and lipofuscin-ferric ferricyanide reduction techniques. Liver from control golden lion tamarins had intrahepatocellular Perls' iron-positive pigment diffusely throughout the lobule with a small amount of Fontana method-positive pigment. Ultrastructurally, hepatocytes from a hyperbilirubinemic tamarin contained pleomorphic electron-dense structures within lysosomes. Transport studies demonstrated secretion of fluorescein isothiocyanate-labeled glycocholic acid, a fluorescent bile acid analog, into bile canaliculi and no secretion of carboxydichlorofluorescein diacetate, a non-bile acid organic anion, by liver from a hyperbilirubinemic tamarin. In contrast, control liver secreted carboxydichlorofluorescein diacetate readily into bile canaliculi. The clinicopathologic presentation of this syndrome in golden lion tamarins is similar to that described for Dubin-Johnson syndrome of human beings.

Defective biliary excretion of epinephrine metabolites in mutant (TR-) rats: relation to the pathogenesis of black liver in the Dubin-Johnson syndrome and Corriedale sheep with an analogous excretory defect

Dubin-Johnson patients, mutant Corriedale sheep and TR- and EHBR mutant rats have recessively inherited defective bile canalicular secretion of many nonbile acid organic anions. The human and ovine mutants have black livers and lysosomal pigment accumulation. The livers in TR- and EHBR mutant rats are not black, and sparse lysosomal pigment accumulation is seen. Previously, we postulated that the unidentified pigment in the Dubin-Johnson syndrome results from the accumulation of tyrosine, phenylalanine and tryptophan metabolites, such as metanephrine, which are normally secreted in bile as organic anions. We tested this hypothesis in TR- rats. 3H-epinephrine was injected intravenously; control rats secreted 2.80% +/- 0.52% of the injected dose in bile as compared with 0.19% +/- 0.07% in TR- rats. From 82% to 90% of biliary radioactivity was due to polar conjugates in control rats and mutant rats. TR- rats retained more of the injected dose in the liver, particularly in lysosomes, and secreted more in urine than did control rats. After feeding control and TR- rats for 4 mo with a rat chow diet supplemented with 4% tyrosine, tryptophan and phenylalanine, the liver did not become grossly black; however, histological and electron microscopic study revealed dense lysosomal pigment accumulation in TR- rats. Intraportal injection of metanephrine resulted in the appearance of black liver in TR- rats that persisted for at least 2 hr and was not associated with pigment accumulation by light or electron microscopic examination.(ABSTRACT TRUNCATED AT 250 WORDS)

Pericanalicular microfilaments of hepatocytes in patients with familial non-hemolytic hyperbilirubinemia

We observed pericanalicular webs (PCW) of liver cells in cases with familial non-hemolytic hyperbilirubinemia using electron microscopy. The area and width of PCW were determined by morphometric methods as a way of quantitating this feature. The mean PCW width was 0.175 +/- 0.003 micron (mean +/- SE) in Dubin-Johnson syndrome and 0.184 +/- 0.005 micron in Rotor's syndrome. In both of these syndromes PCW width was significantly larger than that in Gilbert's syndrome (0.124 +/- 0.003 micron) (p less than 0.01). The mean PCW area was 0.585 +/- 0.017 micron 2 in Dubin-Johnson syndrome and 0.582 +/- 0.030 micron 2 in Rotor's syndrome. Values in these two syndromes were significantly larger than that in Gilbert's syndrome (0.382 +/- 0.014 micron 2) (p less than 0.01). Widths and areas of PCW in these three syndromes were not significantly different between central, intermediate, and peripheral zones of the hepatic lobules. There was a positive correlation between serum direct bilirubin levels and widths or areas of PCW in these syndromes. These results suggested that disturbances of bile flow caused by the dysfunction of pericanalicular microfilaments are partly involved in the pathogenesis of Dubin-Johnson syndrome and Rotor's syndrome.

[Dubin-Johnson syndrome associated with hepatocellular carcinoma--report of an autopsy case]

An autopsy case of Dubin-Johnson syndrome (DJS), associated with hepatocellular carcinoma (HCC), the third such case in Japanese literature, is reported. A 64-year-old man, known to have had jaundice from his childhood, was admitted because of weight loss. Close examination revealed that the patient had DJS with HCC and a right lobectomy of the liver was performed. He died, however, of metastasis of HCC about 36 months later. At autopsy, the liver was found to be brownish-black in color. Microscopic findings of the liver were those common to HCC and chronic active hepatitis, and the brown pigment seen in the hepatocytes was mainly confined to the centrilobular ares. After histochemical and electronmicroscopic study, a close relation between this pigment and lysosome is suspected.

Clinicopathological studies of the Dubin-Johnson syndrome complicated with chronic hepatitis

Eleven patients with Dubin-Johnson syndrome (DJS) were studied clinicopathologically. In three patients with DJS, concomitant chronic hepatitis was observed. They showed long-standing jaundice with the symptoms of general fatigue and anorexia. Laboratory tests revealed mild hypertransaminasemia, elevated serum bilirubin (over 5.0 mg/dl) and a high level of serum Bromsulphalein (BSP) retention at 45 min (above 18%). Two patients complicated with chronic hepatitis showed a rather slow secondary rise in the BSP excretion curve in comparison with the patients who had no complication. One patient accompanied with the most severe fibrosis showed no secondary rise in the BSP excretion curve. After the treatment of the patient with phenobarbital, however, a secondary rise in the BSP excretion curve appeared and the serum BSP level was also significantly decreased at all points on the BSP excretion curve. Histological examination of the liver revealed the decreased number of the Dubin-Johnson pigments in the patients complicated with chronic hepatitis. Laparoscopically, a patient with a chronic aggressive hepatitis showed a dark gray decololization of the liver surface and another patient with a chronic aggressive hepatitis showed a black color of the liver surface with partial nodule formation.

A black hepatocellular carcinoma with Dubin-Johnson-like pigment and Mallory bodies: a histochemical and ultrastructural study

A hepatocellular carcinoma which was predominately black was surgically excised from a noncirrhotic, asymptomatic 62-year-old white man. Brown-black, pigment granules, found only in the tumor cells, were histochemically and ultrastructurally identical to the hepatocellular pigment found in Dubin-Johnson syndrome. The latter pigment is thought to accumulate as a consequence of a genetically determined abnormality in the excretion of catecholamines and related substances. It is postulated that the pigment formation in this tumor developed via a similar, though epigenetic, mechanism. This occurrence has not been previously described. Unusual PAS-negative, globular cytoplasmic inclusions were also found in the tumor cells and these proved to be Mallory bodies by electron microscopy.

[Contribution to the diagnosis of Dubin-Johnson syndrome]

Eight patients with Dubin-Johnson's syndrome have been reported. It appoints the greatest casuistry about the theme in our country. The coincidence covers all the aspects of the disease except by the fact that we emphasize, as a matter of interest, that we were able to visualize the gallblader and the biliary tract through oral cholecystography visualize the gallblader and the biliary tract through oral cholecystography or through intravenous cholangiography, in all the patients who have been studied. It doesn't agree with the class descriptions in which these exams have negative results. So we point out the possibility of this disease's existence in spite of the radiographic visulaization of biliary tract, particularly in those patients with moderated hepatic pigment-deposit. Refering to pathologic anathomy we remark the importance in the search of the pigment charactiristic of the Dublin-Johnson's syndrome in all the liver histopathologic exams. Besides, we consider it valuable to make the Fontana-Masson coloration in those patients who present negative pigment reaction to iron. The systematic examinations of the cytoplasmatic pigments will allow us to diagnose the disease even in the cases with minimum and latent characteristics.

Familial nonhemolytic jaundice with free and conjugated hyperbilirubinemia, elevated serum bile acids, and liver pigmentation

We have described an 11-year-old patient with nonhemolytic hyperbilirubinemia, elevated serum bile acids, and liver pigmentation. The Bromsulphalein clearance was not typical of that seen in the Dubin-Johnson syndrome, but there was a secondary rise at 120 min. The abnormalities involving several organic anions and liver histology are compared to those seen in other types of familial nonhemolytic jaundice.

Dublin-Johnson syndrome with some unusual features in a Chinese family

Three cases of chronic nonhaemolytic jaundice with conjugated bilirubin in the serum are described in a Chinese family. Bromsulphthalein excretion tests gave results typical of the Dubin-Johnson syndrome. Liver histology in the proband showed cytoplasmic pigment of the lipofuscinmelanin variety, and intravenous cholecystography failed to show visualisation of the gallbladder. Unusual findings included onset during the neonatal period in the proband and the presence of some iron pigment in the hepatic cells with a little canalicular cholestasis. It is suggested that the infant may have had a concomitant nonspecific hepatitis. These cases are regarded as belonging to a disease group in which the Dubin-Johnson syndrome is at one end of a spectrum. The mode of inheritance is discussed.

[Hyperbilirubinemias; diagnostic and therapeutic aspects]

In the newborn functional disturbances of bilirubin metabolism may be threatening for the life of affected infants. Apart from states with massive overproduction of bilirubin caused by hemolytic crisis functional hyperbilirubinemias in adults represent preponderant hereditary disorders (Gilbert's syndrome, Dubin-Johnson-syndrome, Rotor-syndrome), full compatible with normal life span. Affected subjects are considered as normal persons and should be advised to live a normal life, avoiding however all well-known exogenous factors which may exacerbate the disease. The important clinical and characteristic diagnostic criteria of the mentioned disorders of bilirubin matabolism as well as the possibilities of their symptomatic therapy are discussed.

Mitochondrial pathology in the liver in a patient with the Dubin-Johnson syndrome

Electron microscopy study of a liver biopsy from a patient with the Dubin-Johnson syndrome revealed evidence of severe mitochondrial damage. The changes included membranous whorls, isolated intramitochondrial membranes, myelin figures and large cytoplasmic vacuoles, presumably representing degenerated micochondria. Mitochondrial damage should be looked for in future electron microscopy studies in patients with the Dubin-Johnson syndrome.

Lysosomal changes in liver tissue from patients with the Dubin-Johnson-Sprinz syndrome

1. Clinical, morphological and biochemical data, including data obtained from the application of subcellular fractionation techniques to liver biopsy specimens, are presented for two patients with the Dubin-Johnson-Sprinz (DJS) syndrome. 2. Subcellular fractionation experiments demonstrate that the lysosomes, which have strikingly reduced equilibrium densities, accumulate melanin. Morphological studies confirm the presence of pigments within lysosomes. 3. Although there are increased activities of lysosomal acid hydrolases in the liver tissue from patients with the DJS syndrome, the integrity of these organelles is essentially normal and therefore the accumulation of pigment would not be expected to initiate liver damage. The DJS syndrome is thus a benign type of secondary lysosomal storage disease.