A veterinarian in Thailand was diagnosed with COVID-19 after being sneezed on by an infected cat owned by an infected patient. Genetic study supported the hypothesis of SARS-CoV-2 transmission from the owner to the cat, and then from the cat to the veterinarian.
Biliary atresia (BA) is the most severe form of obstructive cholangiopathy occurring in infants. Definitive diagnosis of BA usually relies on operative findings together with supporting pathological patterns found in the extrahepatic bile duct. In infancy, overlapping clinical patterns of cholestasis can be found in other diseases including biliary hypoplasia and progressive familial intrahepatic cholestasis. In addition, BA has been reported as a phenotype in some rare genetic syndromes. Unlike BA, other cholangiopathic phenotypes have their own established genetic markers. In this study, we used these markers to look for other cholestasis entities in cases diagnosed with BA. DNA from 20 cases of BA, diagnosed by operative findings and histopathology, were subjected to a study of 19 genes associated with infantile cholestasis syndromes, using whole exome sequencing. Variant selection focused on those with allele frequencies in dbSNP150 of less than 0.01. All selected variants were verified by polymerase chain reaction-direct sequencing. Of the 20 cases studied, 13 rare variants were detected in 9 genes: 4 in (Alagille syndrome), 2 in (progressive familial intrahepatic cholestasis [PFIC] type 6), and one each in (Dubin-Johnson syndrome), (PFIC type 2), (Crigler-Najjar syndrome), (Kabuki syndrome), (Mitchell-Riley syndrome), (Fanconi anemia), and (Zimmermann-Laband syndrome). Genetic lesions associated with various cholestatic syndromes detected in cases diagnosed with BA raised the hypothesis that severe inflammatory cholangiopathy in BA may not be a distinct disease entity, but a shared pathology among several infantile cholestatic syndromes.
Genome-wide association studies (GWASs) have identified a genetic associated between
EFEMP1
and biliary atresia (BA). To examine the susceptibility of single nucleotide polymorphisms (SNPs) in
EFEMP1
in Thai BA patients, we performed an analysis of the genetic associations and biological interactions with previously reported key SNPs in
ADD3
, a key gene associated with BA. The study also used high-throughput sequencing to detect novel variants in both genes. In addition, the clinical impact of
EFEMP1
SNPs in terms of survival association was also evaluated. The genotypes of 60 BA patients and 179 controls were evaluated using a TaqMan genotyping assay for rs2501577 and rs17095355 in
ADD3
and rs6761893 and rs727878 in
EFEMP1
. The genotype frequencies were analyzed together with the SNP-SNP interactions. Fine mapping by whole-exome sequencing was performed to identify deleterious variants within both genes, and the survival analysis results were analyzed with the
EFEMP1
SNPs. The recessive genotypes of rs2501577, rs17095355 and rs6761893 showed significantly higher frequencies in the BA patients than the controls, and a logistic regression showed that minor alleles of those SNPs increased the BA risk by ORs of 1.86, 1.67, and 1.84, respectively. Moreover, the SNP-SNP interference suggested that a combination of recessive alleles from the 2 genes resulted in an additive risk to BA. In addition, rare missense variants in the gene coding sequences were identified in 7 cases. Immunohistochemical studies revealed a pattern of ADD3 downregulation and EFEMP1 overexpression in the bile ducts of BA patients. Patients with the AA genotype of rs6761893 had significantly lower 5-year native liver survival (34.0%) than those with AT/TT (75.0%), with a log-rank p value of 0.041. Variants in
EFEMP1
are associated with the occurrence of BA in Thai patients. In addition, these variants have an additive influence on BA risk when combined with
ADD3
variants. Moreover, rs6761893 in
EFEMP1
was indicative of survival in Thai BA patients.
Patient: Female, 2-year-old
Final Diagnosis: Juvenile hyaline fibromatosis
Symptoms: Multiple painless soft tissue masses affecting the ears • forehead • scalp
Medication: —
Clinical Procedure: Excision biopsy • surgery removal
Specialty: Pediatrics and Neonatology • Surgery
Objective:
Rare disease
Background:
Juvenile hyaline fibromatosis is a rare autosomal recessive disorder with unknown prevalence characterized by abnormal development of hyalinized fibrous tissue usually in the skin, mucosa, bone, and often the internal organs. Here, we report the case of a 7-year-old girl from a family with ANTXR2 mutation confirming JHF.
Case Report:
The girl presented with multiple painless soft-tissue swellings affecting the ears, forehead, and scalp. Excisional biopsies of the masses reported positive immunohistochemical staining for collagen type VI in the extracellular matrix area, which indicated collagen VI accumulation. Genetic analysis was performed using whole-exome sequencing. The variants were further validated using Sanger sequencing in trio-based approach. We identified a novel mutation, c.1273_1293delinsTCTTGTGGGTTTGGCT in exon 15 of ANTXR2 gene, leading to a frame-shift of the amino acid from codon 425 to all the rest of the amino acid chain (p.Pro425Serfs). The change of an encoded protein interrupted lysosome-mediated degradation of collagen VI. This finding was compatible with her parents whose genetic tests were both positive for the same heterogenous deletion/insertion mutation. The patient was treated with surgical excision of the tumor masses, which had to be repeated several times due to recurrences.
Conclusions:
This novel mutation in exon 15 of the ANTXR2 gene may help improve understanding of genotype-phenotype correlations for this syndrome and provide the basis for diagnostic testing. A multidisciplinary team approach including genetic molecular testing is required for an accurate diagnosis and management of JHF for conducting genetic counseling for affected families as a part of holistic management.
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