Genotype correlates with clinical course and outcome of children with tight junction protein 2 (TJP2) deficiency-related cholestasis

BACKGROUND AND AIMS

The study aimed to describe the clinical course and outcomes, and analyze the genotype-phenotype correlation in patients with tight junction protein 2 (TJP2) deficiency.

APPROACH AND RESULTS

Data from all children with chronic cholestasis and either homozygous or compound heterozygous mutations in TJP2 were extracted and analyzed. The patients were categorized into 3 genotypes: TJP2-A (missense mutations on both alleles), TJP2-B (missense mutation on one allele and a predicted protein-truncating mutation [PPTM] on the other), and TJP2-C (PPTMs on both alleles). A total of 278 cases of genetic intrahepatic cholestasis were studied, with TJP2 deficiency accounting for 44 cases (15.8%). Of these, 29 were homozygous and 15 were compound heterozygous variants of TJP2 . TJP2-A genotype was identified in 21 (47.7%), TJP2-B in 7 cases (15.9%), and TJP2-C in 16 cases (36.4%), respectively. Patients with the TJP2-C genotype were more likely to experience early infantile cholestasis (87.5% vs. 53.5%, p =0.033), less likely to clear jaundice (12.5% vs. 52.2%, p =0.037), more likely to develop ascites, and had higher serum bile acids. Patients with the TJP2-C genotype were more likely to die or require liver transplantation (native liver survival: 12.5% vs. 78.6%, p <0.001), with a median age at death/liver transplantation of 2.5 years. Cox regression analysis revealed that TJP2-C mutations ( p =0.003) and failure to resolve jaundice ( p =0.049) were independent predictors of poor outcomes.

CONCLUSIONS

Patients with the TJP2-C genotype carrying PPTMs in both alleles had a rapidly progressive course, leading to early decompensation and death if they did not receive timely liver transplantation.

Pediatric combined living donor liver and kidney transplantation for primary hyperoxaluria type 2

We report the case of a 12-year-old boy with primary hyperoxaluria type 2 (PH2) presenting with end-stage renal disease and systemic oxalosis who underwent a combined living donor liver and kidney transplant from 3 donors, 1 of whom was a heterozygous carrier of the mutation. Plasma oxalate and creatinine levels normalized immediately following the transplant and remain normal after 18 months. We recommend combined liver and kidney transplantation as the preferred therapeutic option for children with primary hyperoxaluria type 2 with early-onset end-stage renal disease.

The Need for Culturally Appropriate Food Allergy Management Strategies: The Indian Milk Ladder

BACKGROUND

Cow's milk allergy (CMA) is one of the most common and complex food allergies affecting children worldwide and, with a few exceptions, presents in the first few months of life. Baked-milk-containing diets are well tolerated in the majority of milk-allergic children and allow dietary restrictions to be relaxed. In addition, the early introduction of tolerated forms of allergenic foods to an infant's diet in small amounts may enhance the outgrowth of their milk allergy through oral tolerance induction. The methods of milk introduction vary widely across the globe.

METHODS

We convened an expert group to develop a comprehensive milk ladder based on the calculated milk protein content of Indian foods. To validate the milk ladder, the foods chosen for the ladder were analyzed and the ladder was re-evaluated based on the cooked milk protein content.

RESULTS

Combining expert consensus and validation of milk protein content, we created the world's first milk ladder containing Indian foods. This is the first ladder that provides information on the timing and temperature of cooking, with validated milk protein content.

CONCLUSIONS

This is the first milk ladder based on the unique features of Indian food habits built by the consensus of Indian experts along with international collaboration with laboratory quantification of milk protein in each step. We believe the "The Indian Milk Ladder" will be a very helpful tool for pediatricians helping manage CMA in children as well as their parents and caregivers, not only in India, but in countries world-wide where these foods are commonly consumed.

Kasai Portoenterostomy at a Slightly Delayed Age and Native Liver Survival in Children With Biliary Atresia: Single Center Experience

OBJECTIVES

We studied the modifiable prognostic factors that extend native liver survival at 2 years after Kasai portoenterostomy (KPE).

METHODS

We reviewed hospital records of patients with neonatal cholestasis, with focus on infants diagnosed with biliary atresia in a tertiary care hospital between January, 2014 and May, 2021. We determined the association of outcome with clinical and laboratory variables.

RESULTS

Infants who underwent KPE at a median (IQR) age of 76 (72-79) days had best outcomes, with minimal severe post-KPE complications and 2-year survival rate of 84.6%, compared to other infants (younger and older days at KPE). The median (IQR) weight at KPE in this group was 4.66 (4.2, 5.0) kg.

CONCLUSION

In contrast to traditional recommendations, babies with median age at KPE of 76 days had superior native liver survival (84.6%) and reduced post-KPE complications, as compared to earlier KPE age. Nutritional status and weight of infant at KPE could be associated with this survival difference. This observation needs confirmation through multicentric prospective study.

When Push Comes to Shove! Emergency ABO-Incompatible Pediatric Living Donor Liver Transplant for Acute Wilson's Disease

ABO-incompatible living donor liver transplantation (ABOi-LDLT) is on the rise as a viable option in countries with limited access to deceased donor grafts. While reported outcomes of ABOi-LT in children are similar to ABO- Compatible liver transplant (ABOc-LT), most children beyond 1-2 years of age will need desensitization to overcome the immunological barrier of incompatible blood groups. The current standard protocol for desensitization is Rituximab that targets B lymphocytes and is given 2-3 weeks prior to LT. However, this timeline may not be feasible in children requiring emergency LT for acute liver failure (ALF) or acute-on-chronic liver failure (ACLF). In this emergency situation of ABOi-LT, a safe multipronged approach may be an acceptable alternative solution. We report a child with acute Wilson's disease with rapidly deteriorating liver function who underwent a successful ABOi-LDLT using a rapid desensitization protocol.

Delayed Expulsion of biliary cast after hepaticojejunostomy for post-liver transplantation biliary stricture-better cut than canulate?

BACKGROUND

Biliary strictures after living donor liver transplantation (LDLT) are a significant cause of post-transplant morbidity. Endoscopic therapy is usually the first choice of treatment though surgical treatment may provide better biliary drainage.

METHODS

We report a case of LDLT performed in a child for acute liver failure who developed an anastomotic biliary stricture with biliary cast formation. We performed a Roux en Y hepaticojejunostomy to treat the stricture.

RESULTS

Allograft function improved after surgery with no further episodes of cholangitis. Two months after the surgery, the child passed a large biliary cast in the stools. This reiterates the advantage of wide biliary drainage provided through surgical therapy.

CONCLUSIONS

Surgery for biliary strictures following LDLT may provide superior long term biliary drainage- especially when biliary casts are present.

Fructose-1,6-bisphosphatase deficiency caused by a novel homozygous Alu element insertion in the FBP1 gene and delayed diagnosis

Fructose-1,6-bisphosphatase (FBPase) enzyme deficiency is one of the treatable autosomal recessive inherited metabolic disorders. If diagnosed early, FBPase deficiency has a favorable prognosis. We report the clinical and biochemical findings of a 9.5-year-old female child with FBPase deficiency. FBPase deficiency is caused by a homozygous Arthrobacter luteus (Alu) insertion in the FBP1 gene, reported for the first time.