Low-Phospholipid Associated Cholelithiasis (LPAC) syndrome: A synthetic review

Relationship between Abnormal Lipid Metabolism and Gallstone Formation

Cholelithiasis is a common biliary system disease with a high incidence worldwide. Abnormal lipid metabolism has been shown to play a key role in the mechanism of gallstones. Therefore, recent research literature on the genes, proteins, and molecular substances involved in lipid metabolism during the pathogenesis of gallstones has been conducted. This study aimed to determine the role of lipid metabolism in the pathogenesis of gallstones and provide insights for future studies using previous research in genomics, metabolomics, transcriptomics, and other fields.

Low phospholipid-associated cholelithiasis syndrome, a not uncommon cause of biliary problems and hospital admissions

BACKGROUND AND AIMS

biliary diseases are a major cause of morbidity and mortality for patients and a burden for the healthcare system. The genetic syndrome of low phospholipid-associated cholelithiasis (LPAC) is a little known and rare entity whose treatment with bile salts avoids symptoms, admissions and the need for surgery. The aim of this study was to determine its incidence and characteristics in our center.

METHODS

prospective study performed between February 2021 and September 2022. LPAC was diagnosed if at least two of the following were present: onset of biliary problems < 40 years of age, recurrence of symptoms after cholecystectomy, ultrasound image of hepatolithiasis (multiple echoic foci, comet-tail images, hepatolithiasis with acoustic shadow). Demographic, clinical, genetic (analysis of MDR3 gene mutations) and ultrasound characteristics and their incidence were analyzed in hospital admissions for biliary causes.

RESULTS

thirty-six patients with LPAC were identified. Of these, six were among 237 admissions due to biliary causes in the previous nine months, with an incidence of 2.5 % (95 % CI: 1.17-5.41). By age subgroup, the incidence was 16.7 % in those admitted < 40 years of age and 9.1 % in those < 50. Considering females only, the incidence was 21 % in those admitted < 40 years and 15.8 % in those < 50 years. All patients remained asymptomatic after treatment with ursodeoxycholic acid and there were no new admissions.

CONCLUSIONS

LPAC syndrome is not as uncommon as it may appear, especially in women < 50 years of age admitted with biliary problems. Its correct diagnosis based on simple criteria could avoid a significant number of hospital admissions and unnecessary cholecystectomies.

Considerations for Low Phospholipid-Associated Cholelithiasis (LPAC) Syndrome: Report of Three Cases

Low phospholipid-associated cholelithiasis (LPAC) syndrome is a rare underdiagnosed genetic feature presenting less than 1% of symptomatic cholelithiasis, with variable clinical forms ranging from simple to complications. Diagnosis criteria are recurrent biliary symptomatology occurring in young patients (<40 years old) and/or recurrence after cholecystectomy and/or having a history of biliary gallstones in first-degree relatives and characteristic ultrasound findings. Early detection of this entity, due to the awareness of gastroenterologists, radiologists, and visceral surgeons, will allow an improvement in the quality of life of patients and the prevention of complications. We report three cases of the LPAC syndrome and discuss its different aspects.

Targeted liver ultrasound performed by an expert is the pivotal imaging examination for low phospholipid-associated cholelithiasis

OBJECTIVES

Low phospholipid-associatedcholelithiasis (LPAC) is a clinical syndrome that can be associated with variants in the adenosinetriphosphate-binding cassette subfamily B, member 4 (ABCB4) transporter gene, in a proportion of patients. The diagnosis of LPAC is defined by clinical as well as imaging criteria of intrahepatic hyperechoic foci or microlithiasis and biliary sludge on ultrasound. The aim of the study was to assess the role of imaging in investigating patients presenting with clinical features suggesting a diagnosis of LPAC.

METHODS

Imaging findings in 51 patients with clinical LPAC were retrospectively reviewed. Most patients had been referred with difficult-to-manage biliary pain postcholecystectomy and some with intrahepatic dilated ducts and stones. The diagnosis of LPAC was made on clinical features.

RESULTS

The patients were young with symptom onset at median age 24 years and were mainly female (75%). Ultrasound was performed by an expert in 48/51 and magnetic resonance cholangiopancreatography (MRCP) in 47/51 patients. Targeted liver ultrasound found small hyperechoic foci with comet tail artifacts or posterior acoustic shadowing typical of LPAC in 30/48 (63%) of examinations. However, ultrasound examinations performed before referral for investigation did not report these findings. Intrahepatic duct dilatation was seen in 26/51 (51%) of cases. MRCP did not reliably detect microlithiasis.

CONCLUSIONS

Targeted liver ultrasound performed by an expert aware of the possible diagnosis is the pivotal investigation for patients with clinical features suggesting LPAC. The findings in ultrasound performed before referral suggest LPAC is under-recognized and under-diagnosed.

ABCB4 Mutations in Adults Cause a Spectrum Cholestatic Disorder Histologically Distinct from Other Biliary Disease

BACKGROUND

Mutations in the ABCB4 gene are associated with failure of bile acid emulsification leading to cholestatic liver disease. Presentations range from progressive familial intrahepatic cholestasis type 3 (PFIC3) in childhood, to milder forms seen in adulthood.

AIMS

We sought to characterize adult disease with particular reference to histology which has been hitherto poorly defined.

METHODS

Four unrelated adults (three female, mean age 39 years) and three sisters presenting with cholestatic liver disease in adulthood, associated with variants in the ABCB4 gene, were identified. Clinical review and detailed blinded histopathological analysis were performed.

RESULTS

Two novel pathogenic ABCB4 variants were identified: c.620 T > G, p.(Ile207Arg) and c.2301dupT, p.(Thr768TyrfsTer26). Sub-phenotypes observed included low-phospholipid-associated cholelithiasis syndrome (LPAC), intrahepatic cholestasis of pregnancy (ICP), drug-induced cholestasis, idiopathic adulthood ductopenia, and adult PFIC3. Of note, 5/7 had presented with gallstone complications (4 meeting LPAC definition) and 4/6 females had a history of ICP. Considerable overlap was observed phenotypically and liver transplantation was required in 3/7 of patients. Histologically, cases generally demonstrated ductopenia of the smaller tracts, mild non-ductocentric portal inflammation, bilirubinostasis, significant copper-associated protein deposition, and varying degrees of fibrosis.

CONCLUSIONS

Adults with ABCB4 mutations may harbor a spectrum of cholestatic disease phenotypes and can progress to liver transplantation. We observed a distinct histological pattern which differs from classical biliary disease and describe two novel pathogenic ABCB4 variants. ABCB4 sequencing should be considered in patients with relevant cholestatic phenotypes and/or suggestive histology; accurate diagnosis can guide potential interventions to delay progression and inform family screening.

Low phospholipids associated cholelithiasis syndrome in a young women: A rare case report

Low phospholipid-associated cholelithiasis (LPAC) is a rare, still poorly understood genetic disorder characterized by the association of an ABCB4 mutation and low biliary phospholipid concentration with recurrent cholelithiasis, responsible for the development of intrahepatic lithiasis in adults. The mutation of the ABCB4 gene, which codes for the ABCB4/MDR3 ductal protein, a biliary transporter, leads to precipitation of cholesterol crystals in the bile ducts leading to the formation of intrahepatic stones. The diagnosis should be suspected when at least 2 of the following criteria are present: onset of symptoms before age 40; recurrence of biliary symptoms (biliary colic, jaundice, cholangitis, acute pancreatitis) after cholecystectomy; presence of echogenic foci in the liver indicative of intrahepatic stones or biliary sludge; previous episode(s) of intrahepatic cholestasis during pregnancy; and a family history of gallstones in first degree relatives. Imaging techniques, especially ultrasound, play an important role in the detection of intrahepatic stones. The majority of clinical situations are simple and not serious, often managed by medical treatment with ursodeoxycholic acid, but certain complicated forms may require more invasive endoscopic or surgical treatment. We report a case of a 43-year-old woman, cholecystectomized 5 years ago, who presented with liver colic-like pain with cytolysis and biological cholestasis. Ultrasound and MRI showed the presence of intrahepatic calculi disseminated along the bile duct pathway creating a comet tail appearance and generating a posterior shadow cone. The interrogation of the patient showed that her sister was being followed for LPAC syndrome. The diagnosis of LPAC syndrome was retained and the patient was put under medical treatment with ursodeoxycholic acid with regular clinical, biological and radiological follow-up.

Review article: diagnostic and therapeutic approach to persistent abdominal pain beyond irritable bowel syndrome

BACKGROUND

Persistent abdominal pain (PAP) poses substantial challenges to patients, physicians and healthcare systems. The possible aetiologies of PAP vary widely across organ systems, which leads to extensive and repetitive diagnostic testing that often fails to provide satisfactory answers. As a result, widely recognised functional disorders of the gut-brain interaction, such as irritable bowel syndrome and functional dyspepsia, are often diagnosed in patients with PAP. However, there are a number of less well-known differential diagnoses that deserve consideration.

AIM

To provide a comprehensive update on causes of PAP that are relatively rare in occurrence.

METHODS

A literature review on the diagnosis and management of some less well-known causes of PAP.

RESULTS

Specific algorithms for the diagnostic work-up of PAP do not exist. Instead, appropriate investigations tailored to patient medical history and physical examination findings should be made on a case-by-case basis. After a definitive diagnosis has been reached, some causes of PAP can be effectively treated using established approaches. Other causes are more complex and may benefit from a multidisciplinary approach involving gastroenterologists, pain specialists, psychologists and physiotherapists. This list is inclusive but not exhaustive of all the rare or less well-known diseases potentially associated with PAP.

CONCLUSIONS

Persistent abdominal pain (PAP) is a challenging condition to diagnose and treat. Many patients undergo repeated diagnostic testing and treatment, including surgery, without achieving symptom relief. Increasing physician awareness of the various causes of PAP, especially of rare diseases that are less well known, may improve patient outcomes.

Clinical, biological, radiological, and genetic study of LPAC syndrome in Tunisian patients

BACKGROUND AND STUDY AIMS

Low phospholipid-associated cholelithiasis (LPAC) syndrome is a form of cholelithiasis associated with the ABCB4 gene mutation. The defects of the protein ABCB4 encoded by this gene promote the formation of biliary cholesterol microcalculations. ABCB4 screening is negative in a significant proportion of patients.

PATIENTS AND METHODS

An analytical study of the epidemiological, clinical, biological, and radiological characteristics of 19 patients was conducted, followed by Sanger-type sequencing of the 27 exons encoding the ABCB4 gene.

RESULTS

Our results showed a female predominance, symptomatic vesicular lithiasis predominance, and a high frequency of biliary complications in patients carrying an ABCB4 mutation. Normal ​​ liver enzyme values were found in 84.2% of the cases. Intrahepatic hyperechoic foci were present in 68.4%. Molecular analysis detected a pathogenic mutation of the ABCB4 gene in 31.57% of patients. The mutations found were a nonsense mutation and three missense mutations, including two new mutations.

CONCLUSION

Our epidemiological, clinical, and genetic results concord with previous studies of LPAC syndrome. Two of the mutations we found have never been detected in patients with LPAC. The low percentage of ABCB4 gene mutations can be explained by the absence of studies of other genes involved in bile acid homeostasis besides the ABCB4 gene and by the inclusion criteria used in this study.

Novel ABCB4 mutations in an infertile female with progressive familial intrahepatic cholestasis type 3: A case report

BACKGROUND

Mutations that occur in the ABCB4 gene, which encodes multidrug-resistant protein 3, underlie the occurrence of progressive familial intrahepatic cholestasis type 3 (PFIC3). Clinical signs of intrahepatic cholestasis due to gene mutations typically first appear during infancy or childhood. Reports of PFIC3 occurring in adults are rare.

CASE SUMMARY

This is a case study of a 32-year-old infertile female Chinese patient with a 15-year history of recurrent abnormal liver function. Her primary clinical signs were elevated levels of alkaline phosphatase and γ-glutamyl transpeptidase. Other possible reasons for liver dysfunction were eliminated in this patient, resulting in a diagnosis of PFIC3. The diagnosis was confirmed using gene detection and histological analyses. Assessments using genetic sequencing analysis indicated the presence of two novel heterozygous mutations in the ABCB4 gene, namely, a 2950C>T; p.A984V mutation (exon 24) and a 667A>G; p.I223V mutation (exon 7). After receiving ursodeoxycholic acid (UDCA) treatment, the patient's liver function indices improved, and she successfully became pregnant by in vitro fertilization. However, the patient developed intrahepatic cholestasis of pregnancy in the first trimester. Fortunately, treatment with UDCA was safe and effective.

CONCLUSION

These novel ABCB4 heterozygous mutations have a variety of clinical phenotypes. Continued follow-up is essential for a comprehensive understanding of PFIC3.

Low Phospholipid-Associated Cholelithiasis: Contribution of Imaging in Two Cases

Low phospholipid-associated cholelithiasis (LPAC) is a genetic disease responsible for the development of intrahepatic lithiasis. It is retained in the presence of two of the following three criteria: age of onset of biliary symptoms less than 40 years; echogenic intrahepatic images or microlithiasis; and the recurrence of biliary clinical signs after cholecystectomy. The majority of clinical situations are simple and not serious, but some complicated forms may require more invasive endoscopic or surgical treatments. By presenting two case studies, we illustrated and summarized the different aspects of this entity.

Combined Mutations of Canalicular Transporter Proteins Causing Low Phospholipid-Associated Cholelithiasis and Transient Neonatal Cholestasis in an Infant

Low phospholipid-associated cholelithiasis syndrome is characterized by the development of cholelithiasis in early adulthood (<40 years of age) but is rarely diagnosed in childhood. It is associated with gene sequence variants in the ABCB4 gene encoding the multidrug resistance protein 3 which are mostly heterozygous. Transient neonatal cholestasis has been reported with heterozygous mutations in both ABCB4 and ABCB11 (Bile Salt Exporter Protein). We report a 3-month-old male with cholelithiasis and transient neonatal cholestasis in the setting of combined pathogenic heterozygous mutations in the genes ABCB4 and ABCB11. Initiation of ursodeoxycholic acid therapy led to a resolution of the cholestasis and gall stones. Our case highlights the complex nature of the genetics of cholestatic disorders.

A novel compound heterozygous mutation in ABCB4 gene in a pedigree with progressive familial intrahepatic cholestasis 3: a case report

Progressive familial intrahepatic cholestasis (PFIC) includes a group of genetic autosomal recessive disorders that predominantly affects young children and results in early-onset progressive liver damage. Variations in ABCB4 have been shown to cause PFIC3. However, the association between ABCB4 genotype and clinical manifestations remains unclear. We investigated the clinical manifestations and genetic features of a Chinese Han pedigree with PFIC3. A 15-year-old boy, with high-serum gamma-glutamyl transferase (γ-GT) cholestatic cirrhosis, was diagnosed with PIFC3. After ursodeoxycholic acid (UDCA) treatment, the boy stayed in a relatively stable state with mild itching, and elevated γ-GT exhibited a remarkable decrease. Genetic testing identified a novel compound heterozygous mutation L842P/V1051A in ABCB4, which was inherited from his mother and father, respectively. Several predictive software suggested that these two mutations are pathogenic. Interestingly, the same compound heterozygous mutation was also found in his two sisters, one of whom had a history of intrahepatic cholestasis of pregnancy (ICP) and the other had asymptomatic gallstones. Therefore, this novel compound heterozygous mutation L842P/V1051A caused a continuum of ABCB4-related diseases including ICP, cholelithiasis and PFIC3 in our pedigree. The inconsistency between genotypes and phenotypes may be influenced by other factors. Genetic testing will be useful for diagnosis and genetic counseling.

Low-phospholipid-associated cholelithiasis syndrome: Prevalence, clinical features, and comorbidities

Background & Aims

Low-phospholipid-associated cholelithiasis (LPAC) syndrome, a rare genetic form of intrahepatic cholelithiasis in adults, is still poorly understood. We report the results of the largest-ever case-control study of patients with LPAC syndrome aiming to assess the prevalence, clinical features, and comorbidities of the disease.

Methods

We included all LPAC cases diagnosed between 2001 and 2016 in 11 French centres. Controls consisted of all patients who underwent a cholecystectomy for common gallstone disease in a single non-academic centre over 1 year. A logistic regression analysis was used to identify the clinical features associated with LPAC syndrome across several patient strata with increasing levels of diagnostic confidence. The ratio between the incident cases of LPAC syndrome and the total number of cholecystectomies for gallstones was used to assess the relative prevalence of the disease.

Results

In this study, 308 cases and 206 controls were included. LPAC syndrome accounted for 0.5–1.9% of all patients admitted with symptomatic gallstone disease. Age at first symptoms <40 years, absence of overweight, persistence of symptoms after cholecystectomy, intrahepatic micro- or macrolithiasis, common bile duct (CBD) lithiasis, and no history of cholecystitis were independently associated with LPAC diagnosis. ATP-binding cassette subfamily B member 4 (ABCB4) variants, present in 46% of cases, were associated with CBD lithiasis, chronic elevation of gamma-glutamyltransferase (GGT), and personal or family history of hepato-biliary cancer.

Conclusions

In this case-control study, LPAC syndrome accounted for approximately 1% of symptomatic cholelithiasis in adults. In addition to pre-established diagnostic criteria, normal weight, CBD lithiasis, and no history of cholecystitis were significantly associated with the syndrome. ABCB4 gene variations in patients with LPAC were associated with CBD lithiasis, chronic cholestasis, and a personal or family history of hepato-biliary cancer.

Lay summary

In the largest case-control study ever conducted in patients with LPAC syndrome, a rare genetic form of intrahepatic cholelithiasis in young adults, LPAC syndrome was found in approximately 1% of all patients admitted to the hospital for symptomatic gallstones and, in addition to the pre-established characteristics of the syndrome (age at first symptoms <40 years, recurrence of symptoms after cholecystectomy, and/or imaging evidence of intrahepatic microlithiasis), was associated with lower BMI, higher prevalence of common bile duct stones, and lower incidence of acute cholecystitis. ABCB4 gene variants, which were detected in about half of cases, were associated with common bile duct stones and a personal or family history of hepato-biliary cancer.

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Low-phospholipid-associated cholelithiasis (LPAC) syndrome affects approximately 1% of adults with symptomatic cholelithiasis.

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Normal weight, common bile duct stones, and lack of cholecystitis are clinical features significantly associated with this syndrome.

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ABCB4 variants in patients with LPAC may be associated with an increased personal or family risk of hepato-biliary cancer.

Should patients with symptomatic cholelithiasis before 30 years of age be tested for ABCB4 gene mutations?

BACKGROUND AND AIMS

Low phospholipid-associated cholelithiasis syndrome (LPAC) is characterized by recurrent symptomatic cholelithiasis in young adults associated with ABCB4 gene mutations. Current diagnosing criteria are complex and heterogeneous, making this a largely underdiagnosed entity. Also, although recommended, genetic testing is not necessary for the diagnosis and its real advantages are not clear. The aim of our study was to explore the prevalence of ABCB4 mutations in symptomatic patients with cholelithiasis before the age of 30.

METHODS

We conducted a multicentric prospective cohort study including patients with symptomatic cholelithiasis presenting before 30 years of age in 4 Portuguese centres between January 2017 and December 2019. ABCB4 gene was analyzed by next generation sequencing (NGS) including all exons and flanking regions. In 17/32 patients ABCB11 and ATP8B1 variants were also analyzed by NGS.

RESULTS

Thirty-two patients were included (75% females, median age of symptom onset was 23 ± 5 years). We found that 8/32 (25%) patients had mutations in ABCB4 gene, 3/17 (18%) in ATP8B1 gene and 1/17 (6%) in ABCB11 gene. 44% (8/18) of patients with LPAC syndrome criteria had identified variants, while the prevalence of mutations in patients with symptoms onset before 30 as sole criteria was 29%.

CONCLUSION

Our results suggest that LPAC should be systematically suspected and investigated in patients with symptomatic cholelithiasis before age of thirty, but genetic testing should only be attempted in patients complying with the more stringent LPAC criteria.

Low phospholipid-associated cholelithiasis syndrome: A rare cause of acute pancreatitis that should not be neglected

BACKGROUND

Low phospholipid-associated cholelithiasis (LPAC) syndrome is a very particular form of biliary lithiasis with no excess of cholesterol secretion into bile, but a decrease in phosphatidylcholine secretion, which is responsible for stones forming not only in the gallbladder, but also in the liver. LPAC syndrome may be underreported due to a lack of testing resulting from insufficient awareness among clinicians.

AIM

To describe the clinical and radiological characteristics of patients with LPAC syndrome to better identify and diagnose the disease.

METHODS

We prospectively evaluated all patients aged over 18 years old who were consulted or hospitalized in two hospitals in Paris, France (Bichat University Hospital and Croix-Saint-Simon Hospital) between January 1, 2017 and August 31, 2018. All patients whose profiles led to a clinical suspicion of LPAC syndrome underwent a liver ultrasound examination performed by an experienced radiologist to confirm the diagnosis of LPAC syndrome. Twenty-four patients were selected. Data about the patients’ general characteristics, their medical history, their symptoms, and their blood tests results were collected during both their initial hospitalization and follow-up. Cytolysis and cholestasis were expressed compared to the normal values (N) of serum aspartate and alanine transaminase activities, and to the normal value of alkaline phosphatase level, respectively. The subjects were systematically reevaluated and asked about their symptoms 6 mo after inclusion in the study through an in-person medical appointment or phone call. Genetic testing was not performed systematically, but according to the decision of each physician.

RESULTS

Most patients were young (median age of 37 years), male (58%), and not overweight (median body mass index was 24). Many had a personal history of acute pancreatitis (54%) or cholecystectomy (42%), and a family history of gallstones in first-degree relatives (30%). LPAC syndrome was identified primarily in patients with recurring biliary pain (88%) or after a new episode of acute pancreatitis (38%). When present, cytolysis and cholestasis were not severe (2.8N and 1.7N, respectively) and disappeared quickly. Interestingly, four patients from the same family were diagnosed with LPAC syndrome. At ultrasound examination, the most frequent findings in intrahepatic bile ducts were comet-tail artifacts (96%), microlithiasis (83%), and acoustic shadows (71%). Computed tomography scans and magnetic resonance imaging were performed on 15 and three patients, respectively, but microlithiasis was not detected. Complications of LPAC syndrome required hospitalizing 18 patients (75%) in a conventional care unit for a mean duration of 6.8 d. None of them died. Treatment with ursodeoxycholic acid (UDCA) was effective and well-tolerated in almost all patients (94%) with a rapid onset of action (3.4 wk). Twelve patients’ (67%) adherence to UDCA treatment was considered “good.” Five patients (36%) underwent cholecystectomy (three of them were treated both by UDCA and cholecystectomy). Despite UDCA efficacy, biliary pain recurred in five patients (28%), three of whom adhered well to treatment guidelines.

CONCLUSION

LPAC syndrome is easy to diagnose and treat; therefore, it should no longer be overlooked. To increase its detection rate, all patients who experience recurrent biliary symptoms following an episode of acute pancreatitis should undergo an ultrasound examination performed by a radiologist with knowledge of the disease.