Inherited Liver Diseases: Inherited Liver Diseases: Four More Diseases

0:00Welcome to Board Pearls. This is episode three of three of the Inherited Liver Diseases chapter, in the Liver Disease module. This episode covers four inherited diseases. A man with lower-lobe emphysema and cirrhosis shows how alpha-one antitrypsin deficiency injures the lung and the liver by opposite mechanisms, why the serum level misleads, what each phenotype means, and why augmentation helps only the lung. A teenager with cystic fibrosis and a large spleen shows why that cirrhosis is focal, why a biopsy misleads, why portal hypertension can arrive while the liver still works, and how the modulators are matched to mutations. A woman whose cystic liver presses on her stomach shows the three genetic forms of polycystic liver disease, why symptoms and not cyst number decide treatment, and why the Model for End-Stage Liver Disease, MELD, score undercounts her illness. And an itching infant shows the inherited cholestatic syndromes of childhood, progressive familial intrahepatic cholestasis, PFIC, benign recurrent intrahepatic cholestasis, BRIC, and Alagille syndrome, which are told apart by the gamma-glutamyl transferase, GGT.

1:13Here's the first patient. A forty-four-year-old man who quit smoking five years ago has emphysema, worst in the lower lobes. Now he has an enlarged spleen and low platelets, and his elastography shows cirrhosis. His alpha-one antitrypsin level was reported as normal during a recent chest infection. He drinks a few beers on weekends and takes ibuprofen most days for back pain.

1:36Lower-lobe emphysema at his age with cirrhosis points to alpha-one antitrypsin deficiency, despite his normal level. Alpha-one antitrypsin is a serpin, a serine protease inhibitor made by the liver. It inhibits neutrophil elastase, and also trypsin, collagenase, cathepsin G, proteinase three, and chymotrypsin, so a deficiency injures tissue wherever neutrophil proteases act, in the lung, the arterial wall, and the skin. Inheritance is co-dominant, unlike the recessive hemochromatosis and Wilson disease of the first two episodes, so each SERPINA1 allele contributes to the level and to the risk of misfolding. The Z allele is carried by about one in twenty-five people of European descent, and PiZZ affects about one in sixteen hundred to two thousand births in the United States and Northern Europe.

2:25One protein injures his two organs in opposite ways. The Z mutation, glutamate to lysine at amino acid three forty-two, prevents proper folding, so the protein polymerizes and is trapped in the hepatocyte's endoplasmic reticulum, and the circulating level falls to about fifteen percent of normal. The lung is injured by too little protein in the blood. Without antiprotease, elastase destroys the alveoli, causing early panacinar emphysema that's worst in the lower lobes, even in non-smokers. The liver is injured by too much protein trapped inside its cells, as the Z polymers damage the hepatocytes. So lower-lobe emphysema in a man in his thirties or forties calls for testing, and once the deficiency is found, the liver is watched.

3:11Which organs are at risk depends on the phenotype. PiMM is the wild type, in about ninety-five percent of people, and PiZZ carries the highest risk of liver and lung disease. PiSS and PiSZ have moderately reduced levels, and PiSZ can cause liver disease, because it pairs a polymer-forming Z allele with a poorly secreted S allele. PiMZ heterozygotes have levels of fifty to one hundred milligrams per deciliter, about sixty percent of normal. They rarely get liver disease from the deficiency alone, but it amplifies alcohol, metabolic dysfunction-associated steatotic liver disease, MASLD, and viral hepatitis. PiNull patients make no protein at all, so they get severe early emphysema but no liver disease, because there's nothing to misfold. A thirty-eight-year-old man with severe emphysema, a normal liver, and no detectable protein is PiNull.

4:01His normal level didn't exclude the diagnosis, because the serum level is unreliable. Alpha-one antitrypsin is an acute phase reactant that rises with inflammation, and it falls in advanced cirrhosis of any cause, so a level drawn during a chest infection meant nothing. The standard is Pi typing by isoelectric focusing or SERPINA1 genotyping, and his phenotype is PiZZ. On biopsy, the Z polymers appear as eosinophilic periportal inclusions on hematoxylin and eosin staining, and as globules that stain with periodic acid-Schiff, PAS, and survive diastase on PAS-D. They survive because diastase digests glycogen, and the globules are protein. Prussian blue stains iron, not these globules.

4:47The disease reaches beyond his lungs and liver, and across every age. Persistent neonatal cholestatic jaundice occurs in fifteen to thirty percent of PiZZ infants, and ten to fifteen percent of PiZZ children progress to liver failure in childhood. Adults present with chronic hepatitis or cryptogenic cirrhosis, and once cirrhosis is established, liver cancer develops at about three to five percent a year. About eight percent of deficient adults develop significant liver disease, and it progresses steadily in those who do, so all of them are monitored. Arterial aneurysms with dissection and stroke occur in adults, because the missing brake on elastase weakens the arterial wall, and ulcerative neutrophilic panniculitis is a rare skin manifestation. Alpha-one antitrypsin cirrhosis is the most common metabolic indication for liver transplant.

5:35His treatment splits by organ. Weekly intravenous augmentation with pooled human alpha-one antitrypsin slows his lung decline by replacing circulating anti-elastase, but it doesn't protect his liver, because the polymers inside his hepatocytes aren't helped by more protein in his blood. Smoking and alcohol stop, so his weekend beers end. Nonsteroidal anti-inflammatory drugs, NSAIDs, are avoided in PiZZ at any stage, because they raise the liver's production of alpha-one antitrypsin and worsen the polymer load, so his ibuprofen stops. PiZZ adults need yearly liver tests, a blood count, and ultrasound or elastography, with liver cancer surveillance once they're cirrhotic.

6:16Transplant cures the liver disease, because the recipient takes on the donor's Pi phenotype, and long-term survival in adults is about sixty-five percent. He stops alcohol and NSAIDs, starts augmentation, begins liver cancer surveillance every six months, and is referred for transplant evaluation.

6:38A heterozygote is handled differently. A fifty-one-year-old PiMZ woman with MASLD drinks moderately. She needs no formal surveillance, but she should minimize alcohol, treat her MASLD risk factors, be vaccinated against hepatitis A and B, and not smoke, because her phenotype amplifies any liver injury and the same protease imbalance speeds lung disease in smokers.

6:57Cystic fibrosis is the other inherited disease that damages both the lungs and the liver, but its liver injury starts in the bile ducts. A seventeen-year-old boy with cystic fibrosis is homozygous for F508del and has pancreatic insufficiency. His alkaline phosphatase is three hundred twenty and his GGT one hundred ninety, both rising over a year. His spleen is palpable. His bilirubin, albumin, and international normalized ratio, INR, are normal, and his vitamin D is low. His family asks whether he needs a liver biopsy.

7:32Rising cholestatic enzymes and a palpable spleen in a teenager with cystic fibrosis point to cystic fibrosis liver disease. Cystic fibrosis affects about one in three thousand births in the United States and Northern Europe, and liver disease develops in five to ten percent of patients over time, so every patient's liver tests are watched. In cholangiocytes, the CFTR channel drives chloride and bicarbonate secretion into bile. When it fails, the bile becomes thick and inspissated and mechanically blocks small ducts, and bile acids injure the tissue around them. The result is periductal fibrosis in patches, wherever ducts are plugged, which is focal biliary cirrhosis. The typical picture is a rising alkaline phosphatase and GGT in adolescence or young adulthood, with portal hypertension as the fibrosis advances.

8:21His family's question has a clear answer: usually no biopsy. The diagnosis is clinical, made with ultrasound and FibroScan, because a needle can land in normal liver between scarred patches and falsely reassure. Cholestatic labs, a heterogeneous nodular liver, splenomegaly, and known cystic fibrosis secure it. His ultrasound shows a heterogeneous, nodular liver and a sixteen-centimeter spleen, and his elastography is raised. A near-normal core from a patchy disease would show where the needle went, not what the liver is doing.

8:52His large spleen means portal hypertension, even with normal synthetic function. Periductal fibrosis obstructs flow without destroying hepatocytes, so portal hypertension can arrive while the bilirubin, albumin, and INR are still normal, and waiting for synthetic failure means waiting too long. His raised stiffness and large spleen put him far outside the Baveno seven zone in which endoscopy can be skipped, so he's scoped and has small varices. Chapter twenty-three covers portal hypertension.

9:22His treatment has three parts. Ursodeoxycholic acid, fifteen to twenty milligrams per kilogram a day, a higher dose than in primary biliary cholangitis, stimulates biliary bicarbonate secretion and shifts the bile acid pool toward a relatively non-toxic bile acid, though the evidence in cystic fibrosis liver disease is limited despite wide use. The fat-soluble vitamins A, D, E, and K are replaced, because both cholestasis and pancreatic insufficiency deplete them, and chapter thirty-two covers their monitoring.

9:55The third part treats the channel itself, and the modulator is chosen by mutation. Ivacaftor, a potentiator, restores channel opening in class three mutations such as G551D. Lumacaftor-ivacaftor and tezacaftor-ivacaftor pair a corrector with the potentiator to rescue the F508del processing defect in homozygotes. Elexacaftor-tezacaftor-ivacaftor is the standard for anyone with at least one F508del allele, and it has transformed the lung disease and modified the liver disease by fixing the upstream defect. He continues elexacaftor-tezacaftor-ivacaftor, adds ursodeoxycholic acid and vitamins, and is followed for his varices. Transplant is for end-stage disease, sometimes combined with a lung transplant.

10:45Not every abdominal pain in cystic fibrosis is liver disease. A twenty-two-year-old woman with cystic fibrosis has right upper quadrant pain after meals, gallstones, and normal liver enzymes. Cholesterol gallstones are common in cystic fibrosis, from altered bile composition and impaired gallbladder motility, and the gallbladder is often small or atretic. Her problem is her gallbladder, not cystic fibrosis liver disease, and chapter twenty-seven covers gallstones.

11:16The next inherited liver disease isn't about injury at all, but about size. A fifty-two-year-old woman with autosomal dominant polycystic kidney disease has a liver packed with dozens of cysts. Over a year she's developed early fullness after a few bites, abdominal pain, and shortness of breath lying flat, and she's lost weight. Her liver tests are normal and her kidney function is moderately reduced. A surgeon friend has told her the cysts should all be drained.

11:44She has polycystic liver disease from autosomal dominant polycystic kidney disease, ADPKD, one of three genetic forms. ADPKD, from PKD1 in about eighty-five percent and PKD2 in the rest, produces kidney and liver cysts that grow through abnormal cholangiocyte proliferation and fluid secretion, driven by disordered planar cell polarity signaling. Autosomal recessive polycystic kidney disease, ARPKD, from PKHD1, combines kidney cysts with a mostly fibrotic liver, congenital hepatic fibrosis, and recurrent cholangitis. Isolated polycystic liver disease, without kidney involvement, is autosomal dominant and most often comes from PRKCSH, which encodes hepatocystin, or SEC63. Both are endoplasmic reticulum proteins for folding and trafficking, and their failure disrupts the cholangiocyte cilium. In the dominant forms, each child has a one-in-two chance of carrying the gene. More than ten to twenty cysts on cross-sectional imaging prompts evaluation for a genetic form, while a few simple cysts mean nothing.

12:54Her symptoms, not her cyst count, are why she needs treatment. Most polycystic liver disease causes no symptoms and needs no therapy. Treatment is for pain, for an enlarged liver causing early satiety, for breathlessness from pressure on the diaphragm, and for biliary or vascular obstruction from large cysts, so new cholestasis in a cystic liver calls for a search for an obstructing cyst. She has three of the four and is losing weight. Her normal liver tests mean the tissue between the cysts works, so her disease is size and pressure, not failure.

13:29The same cysts without symptoms need nothing. A forty-six-year-old man has fifteen liver cysts on a computed tomography, CT, scan done for a kidney stone, no kidney cysts, and no symptoms. He likely has isolated polycystic liver disease, and he needs only an explanation.

13:49Her friend's advice to drain every cyst is wrong, because treatment starts with a drug. A somatostatin analog, long-acting octreotide or lanreotide, comes first, reducing cyst fluid secretion through somatostatin receptor two on the biliary epithelium. The effect is modest, a five to ten percent reduction in liver volume over six to twelve months, but that's often enough to relieve compression, so the response is judged at six to twelve months, not sooner. She starts lanreotide, and after nine months her liver volume is down eight percent and her early fullness has eased, but a dominant twelve-centimeter cyst still presses on her stomach.

14:27When a somatostatin analog isn't enough, surgery follows: laparoscopic or open fenestration of dominant cysts, or partial hepatectomy, but only when enough liver tissue remains. She has adequate liver around the cyst, so she has a laparoscopic fenestration of that one cyst, and she improves. With cysts throughout and little normal tissue, resection wouldn't be safe.

14:50Transplant is reserved for massive disease that hasn't responded, or for a combined liver-kidney transplant in advanced ADPKD. Her preserved synthetic function gives her a low calculated MELD despite disabling mass effect, which is why symptomatic polycystic liver disease qualifies for a MELD exception. Chapter twenty-four covers exceptions.

15:12The recessive form looks nothing like hers. A fourteen-year-old boy has kidney cysts, an enlarged spleen, varices, recurrent cholangitis, and normal liver function. He has ARPKD with congenital hepatic fibrosis. His problems are portal hypertension and cholangitis, not cyst mass, so his care is portal hypertension care and treatment of each cholangitis. Caroli disease, intrahepatic biliary ectasia, and Caroli syndrome, the same with congenital hepatic fibrosis, overlap with ARPKD and are covered in chapter twenty-seven.

15:48The last patient returns to cholestasis, this time in a child, where alpha-one antitrypsin deficiency was one of the causes to consider. A seven-month-old boy has had jaundice and intense itching since about three months of age. He scratches until he bleeds, sleeps poorly, and is growing slowly. His bilirubin is high and mostly conjugated, and his bile acids are very high, but his GGT is normal. His first doctor took the normal GGT as reassurance.

16:16Severe itch and conjugated jaundice from early infancy, with very high bile acids and a normal GGT, point to progressive familial intrahepatic cholestasis, and the normal GGT is the clue, not the reassurance. GGT rises when the biliary epithelium is chronically injured, so a low or normal GGT in a clearly cholestatic child means the problem lies upstream, in how the hepatocyte exports bile acids. Because neonatal cholestasis occurs in fifteen to thirty percent of PiZZ infants, a cholestatic infant also gets a Pi phenotype.

16:52The familial cholestatic syndromes split by GGT and by whether they progress. Low-GGT disease is PFIC types one and two, both with severe itch in infancy and progressive liver disease. PFIC one comes from ATP8B1, which encodes FIC1, a phosphatidylserine flippase that keeps the canalicular membrane asymmetric so it can support bile acid transport. PFIC two comes from ABCB11, which encodes BSEP, the bile salt export pump, so bile acids can't leave the hepatocyte and injure it from inside. The two look alike, so genetic testing separates them. His shows two ABCB11 mutations, so he has PFIC two.

17:37His type needs special attention. PFIC two carries the highest risk of liver cancer in childhood, because the retained bile acids drive both injury and oncogenic signaling, and it's the only PFIC in which a raised alpha-fetoprotein, AFP, should prompt cancer surveillance, so his AFP is followed. It can also recur after transplant. Having never made BSEP, the recipient can form antibodies against the donor liver's BSEP and reproduce the export failure. Transplant is reserved for end-stage disease.

18:12His itch is the most urgent problem day to day. The ileal bile acid transporter inhibitors, approved in twenty twenty-one, reduce reabsorption of bile acids in the ileum and shrink the bile acid pool, relieving itch and cholestatic injury. Odevixibat is approved for PFIC, and maralixibat for Alagille syndrome and, since twenty twenty-four, for PFIC. Rifampin, through activation of the pregnane X receptor, and naltrexone, through central opioid blockade, treat refractory itch. Medium-chain triglycerides and fat-soluble vitamins are given because cholestasis impairs ordinary fat absorption. Ursodeoxycholic acid has limited use in PFIC one and two, because changing the composition of the bile acid pool doesn't fix a broken export pump. He starts odevixibat, and within two months he sleeps through the night.

19:07The same genes can cause a milder disease. BRIC types one and two are missense forms of ATP8B1 and ABCB11 with enough residual function for the liver to recover. They cause episodes of intense itch and jaundice lasting weeks, with complete normalization between episodes and no fibrosis. A young adult with several self-limited bouts and normal liver tests between them has BRIC, which is treated symptomatically, with reassurance.

19:37A high GGT points to a different gene. A nineteen-year-old woman has gallstones, including stones inside her liver, cholestatic liver tests, and a high GGT. She has PFIC three, from ABCB4, which encodes MDR3. It's the only high-GGT PFIC, and it can present in later childhood or adulthood. MDR3 moves phosphatidylcholine into bile. Without it, unbuffered bile acids injure the biliary epithelium, which raises the GGT, and cholesterol falls out of solution and forms stones, including stones inside the liver. Ursodeoxycholic acid helps here, because the composition of the bile acid pool is the problem, so she starts it.

20:24Some cholestatic children have findings outside the liver. A two-year-old girl has cholestasis and itch, deep-set eyes, a broad forehead, a pointed chin, a murmur from peripheral pulmonic stenosis, butterfly vertebrae on x-ray, and posterior embryotoxon on slit-lamp examination. She has Alagille syndrome, which is autosomal dominant, from JAG1 in about ninety-four percent, including small deletions of chromosome twenty that involve JAG1, and from NOTCH2 in about one to two percent. JAG1-NOTCH signaling drives the embryonic development of bile ducts, the heart, and the skeleton, so losing one copy causes bile duct paucity, cardiac outflow malformations, and vertebral arch defects together.

21:09The triad is butterfly vertebrae, peripheral pulmonic stenosis, and posterior embryotoxon, and the characteristic facies are nearly universal. The liver disease is cholestatic enzymes and itch, progressing to cirrhosis in a subset, and she starts maralixibat. The diagnosis comes from examining the heart, the vertebrae, and the eyes.

21:30Here are the traps the boards set in these patients. A normal alpha-one antitrypsin level during inflammation doesn't exclude deficiency. Augmentation doesn't protect the liver. PAS-diastase globules aren't Prussian blue iron. PiSZ can cause liver disease, and PiMZ amplifies other injury. PiNull doesn't cause liver disease. NSAIDs are avoided in PiZZ. And cancer surveillance starts once cirrhosis develops.

21:55The cystic fibrosis traps come next. A normal biopsy doesn't rule out cystic fibrosis liver disease. Varices are looked for without waiting for synthetic failure. Fat-soluble vitamins are replaced, and the ursodeoxycholic acid dose is higher than in primary biliary cholangitis. The modulator has to match the mutation. And gallbladder pain isn't liver disease.

22:20The polycystic traps follow. Cysts without symptoms aren't treated, cyst count doesn't decide treatment, and draining every cyst isn't the answer. Surgery comes after a trial of a somatostatin analog, and only with enough liver left. MELD doesn't reflect mass effect. And the fibrotic liver of ARPKD isn't the cystic liver of ADPKD.

22:42The cholestatic traps close the list. A normal GGT doesn't rule out PFIC. Ursodeoxycholic acid isn't the answer in PFIC one or two. PFIC two needs AFP follow-up and can recur after transplant. PFIC three can first appear in a young adult. BRIC doesn't cause fibrosis. And Alagille syndrome is missed unless the heart, vertebrae, and eyes are examined.

23:07So, start to finish. Diagnose alpha-one antitrypsin deficiency by phenotype or genotype. PiZZ damages the lung through lost antiprotease and the liver through retained Z polymers, which are PAS-positive and diastase-resistant, so augmentation helps the lungs only. PiSZ can cause liver disease, PiNull spares the liver, and PiMZ amplifies other injury. Monitor PiZZ adults yearly, survey them once they're cirrhotic, stop smoking, alcohol, and NSAIDs, and remember that transplant cures the liver.

23:41Cystic fibrosis liver disease is focal biliary cirrhosis from thick bile, diagnosed by labs, ultrasound, and elastography rather than biopsy, and portal hypertension can come before synthetic failure. Give ursodeoxycholic acid at fifteen to twenty milligrams per kilogram, vitamins A, D, E, and K, and a modulator matched to the mutation.

24:04In polycystic liver disease, symptoms decide. Start with a somatostatin analog, then fenestration or resection when enough liver remains, and transplant with a MELD exception, combined with a kidney in advanced ADPKD.

24:19Separate the childhood cholestatic syndromes by GGT. Low GGT with severe itch in infancy is PFIC one or two, and PFIC two needs AFP follow-up and can recur after transplant. High GGT is PFIC three, with stones inside the liver and a response to ursodeoxycholic acid. BRIC is episodic and resolves completely. Treat itch with odevixibat or maralixibat, or with rifampin or naltrexone. Alagille syndrome combines bile duct paucity with peripheral pulmonic stenosis, butterfly vertebrae, and posterior embryotoxon.

24:55That completes the Inherited Liver Diseases chapter. The next chapter is portal hypertension and the complications of cirrhosis.

25:03For the full chapter, the practice vignettes, and the topic-tagged question bank, head to board pearls dot com. You'll find the rest of the series on Apple Podcasts, Spotify, or wherever you listen to podcasts. That brings us to the end of episode three of three of chapter twenty-two, and I'll see you in the next one.