Multiple hepatic adenomas in a child with microvillus inclusion disease

Fetal Bowel Abnormalities Suspected by Ultrasonography in Microvillus Inclusion Disease: Prevalence and Clinical Significance

Microvillus inclusion disease (MVID) is a rare, inherited, congenital, diarrheal disorder that is invariably fatal if left untreated. Within days after birth, MVID presents as a life-threatening emergency characterized by severe dehydration, metabolic acidosis, and weight loss. Diagnosis is cumbersome and can take a long time. Whether MVID could be diagnosed before birth is not known. Anecdotal reports of MVID-associated fetal bowel abnormalities suspected by ultrasonography (that is, dilated bowel loops and polyhydramnios) have been published. These are believed to be rare, but their prevalence in MVID has not been investigated. Here, we have performed a comprehensive retrospective study of 117 published MVID cases spanning three decades. We find that fetal bowel abnormalities in MVID occurred in up to 60% of cases of MVID for which prenatal ultrasonography or pregnancy details were reported. Suspected fetal bowel abnormalities appeared in the third trimester of pregnancy and correlated with postnatal, early-onset diarrhea and case-fatality risk during infancy. Fetal bowel dilation correlated with MYO5B loss-of-function variants. In conclusion, MVID has already started during fetal life in a significant number of cases. Genetic testing for MVID-causing gene variants in cases where fetal bowel abnormalities are suspected by ultrasonography may allow for the prenatal diagnosis of MVID in a significant percentage of cases, enabling optimal preparation for neonatal intensive care.

Liver Transplantation for Hepatic Adenoma: A UNOS Database Analysis and Systematic Review of the Literature

BACKGROUND

Liver transplantation (LT) has been employed for hepatic adenoma (HA) on a case-oriented basis. We aimed to describe the characteristics, waitlist, and post-LT outcomes of patients requiring LT for HA.

METHODS

All patients listed or transplanted for HA in the United States were identified in the United Network for Organ Sharing (UNOS) database (1987-2020). A systematic literature review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis statement.

RESULTS

A total of 199 HA patients were listed for LT in UNOS and the crude waitlist mortality was 9.0%. A total of 142 HA patients underwent LT; 118 of these were among those listed with an indication of HA who underwent LT, and 24 were diagnosed incidentally. Most did not experience hepatocellular carcinoma transformation (89.4%). Over a median follow-up of 62.9 mo, death was reported in 18.3%. The 1-, 3-, and 5-y patient survival rates were 94.2%, 89.7%, and 86.3% in the UNOS cohort. The systematic review yielded 61 articles reporting on 99 nonoverlapping patients undergoing LT for HA and 2 articles reporting on multicenter studies. The most common LT indications were suspected malignancy (39.7%), unresectable HA (31.7%), and increasing size (27.0%), whereas 53.1% had glycogen storage disease. Over a median follow-up of 36.5 mo, death was reported in 6.0% (n=5/84). The 1-, 3-, and 5-y patient survival rates were all 95.0% in the systematic review.

CONCLUSIONS

LT for HA can lead to excellent long-term outcomes in well-selected patients. Prospective granular data are needed to develop more optimal selection criteria and further improve outcomes.

Pediatric Hepatocellular Adenomas: The Influence of Age and Syndrome on Subtype

Hepatocellular adenomas are rare in children. A large study focused on pediatric patients has not been undertaken. A natural language search was performed at 5 institutions for hepatocellular adenomas in patients younger than 21 years old. Clinical characteristics as well as immunohistochemical staining profile was reviewed and adenomas subtyped per standard classification. Patients were divided into prepubescent and postpubescent age group. Thirty-one patients were included. Eleven (35%) were male and 10 (32%) were prepubescent. Fifteen (54%) of 28 patients with known clinical histories had adenomas associated with a syndrome. The percentage of the different adenoma subtypes was: 16% β-catenin activated, 10% combined inflammatory and β-catenin activated, 29% HFN1α-inactivated, 35% inflammatory, and 10% unclassified subtype by immunohistochemical staining. Interestingly 53% of patients with syndromes were male, while 85% of patients in the nonsyndromic group were female. The total number of β-catenin activated tumors was greater in the syndromic group (5/15, 33%) and prepubescent group (5/10, 50%) than in the nonsyndromic group (2/13, 16%) and postpubescent group (3/21, 14%), P=0.4 and 0.07, respectively. Inflammatory type adenoma was more frequent in the postpubescent (10/21, 48%) than in the prepubescent group (1/10, 10%), P=0.06, trending toward significance. Pediatric patients with hepatocellular adenomas frequently have syndromes, especially in the prepubescent group. In patients with syndromes a greater percentage of adenomas were β-catenin activated. In patients without a known syndrome the distribution of hepatocellular adenoma subtypes appears similar to adults.

Congenital diarrhea in a newborn infant: A case report

BACKGROUND

Microvillus inclusion disease (MVID) is a rare autosomal recessive cause of severe congenital diarrhea with significant morbidity and mortality. Definitive treatment involves bowel transplant. The diagnosis of this condition can be challenging and a few genetic panels are available for the identification of the most common mutations. We present the case of an infant with MVID due to a mutation not reported in the literature before.

CASE SUMMARY

We report the case of an infant transferred to our institution with severe diarrhea of unknown etiology, failure to thrive, and significant metabolic derangements. An extensive work-up including stool studies for common gastrointestinal pathogens, abdominal ultrasound, esophagogastroduodenoscopy with duodenal biopsy and flexible sigmoidoscopy failed to reveal a diagnosis. Multiple dietary and formula regimens were introduced but all resulted in voluminous diarrhea. She remained on total parenteral nutrition (TPN) for the duration of her hospital stay. Genetic testing was done and she was subsequently found to have a novel mutation in the MYO5B gene [homozygous mutation for MYO5B c.1462del, p. (Ile488Leufs*93)] giving us the diagnosis of MVID. She remains on TPN while awaiting bowel transplant at the time of the compilation of this case report.

CONCLUSION

We report a novel mutation involved in MVID and highlight the importance of considering this disease when faced with a newborn presenting with life threatening diarrhea. At the time of this publication, 232 allelic variations of this gene (MIM#606540) exist in National Center for Biotechnology Information's database. Our patient's mutation has not been reported in literature as a cause of MVID.

An overview and online registry of microvillus inclusion disease patients and their MYO5B mutations

Microvillus inclusion disease (MVID) is one of the most severe congenital intestinal disorders and is characterized by neonatal secretory diarrhea and the inability to absorb nutrients from the intestinal lumen. MVID is associated with patient-, family-, and ancestry-unique mutations in the MYO5B gene, encoding the actin-based motor protein myosin Vb. Here, we review the MYO5B gene and all currently known MYO5B mutations and for the first time methodologically categorize these with regard to functional protein domains and recurrence in MYO7A associated with Usher syndrome and other myosins. We also review animal models for MVID and the latest data on functional studies related to the myosin Vb protein. To congregate existing and future information on MVID geno-/phenotypes and facilitate its quick and easy sharing among clinicians and researchers, we have constructed an online MOLGENIS-based international patient registry (www.MVID-central.org). This easily accessible database currently contains detailed information of 137 MVID patients together with reported clinical/phenotypic details and 41 unique MYO5B mutations, of which several unpublished. The future expansion and prospective nature of this registry is expected to improve disease diagnosis, prognosis, and genetic counseling.