Neonatal sclerosing cholangitis with novel mutations in DCDC2 (doublecortin domain-containing protein 2) in Chinese children

BACKGROUND

Neonatal sclerosing cholangitis (NSC) is a rare and severe autosomal recessive inherited liver disease with mutations in DCDC2, commonly requiring liver transplantation (LT) for decompensated biliary cirrhosis in childhood.

METHODS

The information of four Chinese patients with NSC caused by mutations in DCDC2 from Children's Hospital of Fudan University were gathered. The four patients' clinicopathological and molecular features were summarized by clinical data, liver biopsy, immunohistochemical, and molecular genetic analysis.

RESULTS

All patients presented with jaundice, hepatosplenomegaly, hyperbilirubinemia and bile embolism, and high serum γ-glutamyl transferase activity (GGT). Liver biopsies revealed varying degrees of bile duct hyperplasia, portal-tract inflammation, and/or fibrosis. Whole-exome sequencing (WES) found novel heterozygous variants of c.1024-1G > T /p.? and c.544G > A /p. Gly182Arg in the DCDC2.

CONCLUSION

This study expands the genetic spectrum of DCDC2 in NSC.

Defining pathogenicity of NOTCH2 variants for diagnosis of Alagille syndrome type 2 using a large cohort of patients

BACKGROUND AND AIMS

Alagille syndrome (ALGS) type 2 caused by mutations in NOTCH2 has genotypic and phenotypic heterogeneity. Diagnosis in some atypical patients with isolated hepatic presentation could be missed.

METHODS

Using 2087 patients with paediatric liver manifestations, NOTCH2 allele frequencies, in-silico prediction, protein domains and clinical features were analysed to define the pathogenicity of NOTCH2 variants for diagnosis of ALGS type 2.

RESULTS

Among 2087 patients with paediatric liver manifestations, significantly more NOTCH2 variants were absent in gnomAD in patients with elevated γ-glutamyltransferase (GGT) (p = .041). Significantly more NOTCH2 variants which were absent in gnomAD were located in protein functional domains (p = .038). When missense variants were absent in gnomAD and predicted to be pathogenic by at least three out of seven in-silico tools, they were found to be significantly associated with liver manifestations with elevated GGT (p = .003). Comparing this to patients with likely benign (LB) variants, the patients with likely-pathogenic (LP) variants have significantly more liver manifestations with elevated GGT (p = .0001). Significantly more patients with LP variants had extra-hepatic phenotypes of ALGS compared with those patients with LB variants (p = .0004).

CONCLUSION

When NOTCH2 variants are absent in gnomAD, null variants and missense variants which were predicted to be pathogenic by at least three in-silico tools could be considered pathogenic in patients with high GGT chronic liver diseases.

Updated clinical and glycomic features of mannosyl-oligosaccharide glucosidase deficiency: Two case reports

BACKGROUND

Mannosyl-oligosaccharide glucosidase (MOGS) deficiency is an extremely rare type of congenital disorder of glycosylation (CDG), with only 12 reported cases. Its clinical, genetic, and glycomic features are still expanding. Our aim is to update the novel clinical and glycosylation features of 2 previously reported patients with MOGS-CDG.

CASE SUMMARY

We collected comprehensive clinical information, and conducted the immunoglobulin G1 glycosylation assay using nano-electrospray ionization source quadruple time-of-flight mass spectrometry. Novel dysmorphic features included an enlarged tongue, forwardly rotated earlobes, a birth mark, overlapped toes, and abnormal fat distribution. Novel imaging findings included pericardial effusion, a deep interarytenoid groove, mild congenital subglottic stenosis, and laryngomalacia. Novel laboratory findings included peripheral leukocytosis with neutrophil predominance, elevated C-reactive protein and creatine kinase, dyslipidemia, coagulopathy, complement 3 and complement 4 deficiencies, decreased proportions of T lymphocytes and natural killer cells, and increased serum interleukin 6. Glycosylation studies showed a significant increase of hypermannosylated glycopeptides (Glc3Man7GlcNAc2/N2H10 and Man5GlcNAc2/N2H5) and hypersialylated glycopeptides. A compensatory glycosylation pathway leading to an increase in Man5GlcNAc2/N2H5 was indicated with the glycosylation profile.

CONCLUSION

We confirmed abnormal glycomics in 1 patient, expanding the clinical and glycomic spectrum of MOGS-CDG. We also postulated a compensatory glycosylation pathway, leading to a possible serum biomarker for future diagnosis.

Neonatal cholestasis is an early liver manifestation of children with acid sphingomyelinase deficiency

Background

Patients with acid sphingomyelinase deficiency (ASMD) may be referred to a hepatologist for liver manifestations. This study summarized the liver manifestations of patients with ASMD in the early disease course.

Methods

This study enrolled ASMD patients diagnosed by genetic tests between July 2016 and December 2020 in a national pediatric liver center. The significance of low High-density lipoprotein cholesterol (HDL-C) for aid diagnosis of ASMD in infancy was explored by reviewing 160 consecutive infants with liver manifestations, who underwent both genetic tests and lipid profile studies, between January 2020 and December 2020.

Results

A total of 7 patients were diagnosed as ASMD, and 10 known disease-causing variants were identified. Hepatosplenomegaly, elevated transaminases, and liver foam cells were observed in all the 7 patients at age ranging from 4 to 31 months. Low HDL-C was detected in 5 patients, cherry red spot in 4 patients, development delay in 3 patients, and interstitial lung diseases in 1 patient. Three ASMD patients developed cholestasis around 1 month of age, and bilirubin levels normalized at age ranging from 3 to 10 months. They had persistently elevated transaminases and hepatosplenomegaly, and died within 4 years of age. Among the 160 infants with liver manifestations, 125 (78.1%) had low HDL-C. Fifty-four had both low HDL-C and splenomegaly, including 48 cholestatic infants, but only 1 (1.9%, 1/54) infant without cholestasis was diagnosed as ASMD.

Conclusions

ASMD can manifest as neonatal cholestasis in the early disease course. Cholestasis is a pitfall when low HDL-C is used for aid diagnosis of ASMD in infants with splenomegaly.

TMEM199-Congenital Disorder of Glycosylation With Novel Phenotype and Genotype in a Chinese Boy

Background: TMEM199-congenital disorder of glycosylation (TMEM199-CDG) is a rare autosomal recessive inherited disease characterized by chronically elevated serum transaminase, decreased serum ceruloplasmin, steatosis and/or fibrosis, TMEM199 mutation, reduced level of TMEM199 protein, and abnormal protein glycosylation.

Methods: The information of a Chinese patient with TMEM199-CDG in the Children’s Hospital of Fudan University was reviewed. The patient’s clinical, pathological, and molecular features were obtained by clinical data study, liver biopsy, immunohistochemistry, and molecular genetic analysis.

Results: A 4-year-old Chinese boy presented with hypertransaminasemia, hypercholesterolemia, elevated alkaline phosphatase, decreased serum ceruloplasmin and serum copper level, and coagulopathy since birth. To the best of our knowledge, novel findings included strabismus, cirrhosis by liver biopsy, reduced expression of TMEM199 by immunohistochemistry, and a frameshift variant of c.128delA/p.Lys43Argfs*25 in the TMEM199 gene.

Conclusion: This case added to the phenotypic and genotypic spectrum of TMEM199-CDG.

The Presence of Vacuolated Kupffer Cells Raises a Clinical Suspicion of Niemann-Pick Disease Type C in Neonatal Cholestasis

Early diagnosis of Niemann-Pick disease type C (NP-C) in neonatal cholestasis is still challenging because splenomegaly is non-specific and oxysterol profiling studies also have a relatively low specificity. This study explores a method for identifying infants with a high clinical suspicion of NP-C in neonatal cholestasis. We reviewed the clinical findings of 9 neonatal cholestatic infants with NP-C genetically diagnosed between January 2015 and December 2020. Seven underwent liver biopsy at ages ranging from 35 to 112 d. Foam cells were only detected in 2 (28.6%, 2/7) liver tissues obtained beyond 3 months of age. However, vacuolated Kupffer cells were detected in all 7 liver tissues. Their significance was explored by using 168 neonatal cholestatic infants, who underwent genetic tests and liver biopsy between January 2018 and December 2020. Of them, 26 detected vacuolated Kupffer cells. Six (23.1%, 6/26) were diagnosed as NP-C, comparing to none of the 142 neonatal cholestatic infants without vacuolated Kupffer cells (χ² = 33.983, p < 0.001). The ratio of positive diagnosis of NP-C was 31.6% (6/19) in neonatal cholestatic infants with both vacuolated Kupffer cells and splenomegaly. Therefore, we conclude that the presence of vacuolated Kupffer cells can raise a high clinical suspicion of NP-C in neonatal cholestatic infants, especially in those with splenomegaly.

Four New Cases of SLC35A2-CDG With Novel Mutations and Clinical Features

SLC35A2-CDG is a rare type of X-linked CDG with more than 60 reported cases. We retrospectively analyzed clinical phenotypes and SLC35A2 genotypes of four cases of SLC35A2-CDG from four unrelated families of Han ethnicity in China. All patients had infantile onset epilepsies that were completely or partly resistant to multiple anti-epileptic medications or ketogenic diet. Three patients had severe developmental delay. All patients were female patients carrying de novo deleterious mutations in SLC35A2 (NM_001042498.2) gene, including one canonical splice-site mutation (c.426+1G > A), one large deletion (c.-322_c.274+1del), and two frameshift mutations leading to premature stop codon (c.781delC/p.Arg289ValfsTer88 and c.601delG/p.Ala201GlnfsTer148). Novel clinical features in some of our patients include anemia, hypertriglyceridemia, hypertonia, small ears, extra folds on earlobes, and maternal oligohydramnios or hypothyroidism during pregnancy. In one patient, concomitant Marfan syndrome was confirmed for having positive family history, carrying a heterozygous known disease-causing mutation in FBN1 gene (c.7240C > T/p.Arg2414Ter), and presence of typical features (rachnodactyly, ventrical septal defect, and mitral valve regurgitation). In conclusion, we expanded clinical phenotype and genetic mutation spectrum of SLC35A2-CDG by reporting four new cases with novel pathogenic variants and novel clinical features.

Pediatric Wilson disease presenting as acute liver failure: Prognostic indices

BACKGROUND

Acute liver failure (ALF) can be a primary presentation of Wilson disease (WD). Mortality rates are high in WD with ALF (WDALF). Predictions of mortality in WDALF vary by model and are sometimes contradictory, perhaps because few patients are studied or WD diagnoses are questionable.

AIM

To determine the outcomes among well-documented WDALF patients and assess mortality model performance in this cohort.

METHODS

We reviewed the medical records of our pediatric WDALF patients (n = 41 over 6-years-old, single-center retrospective study) and compared seven prognostic models (King’s College Hospital Criteria, model for end-stage liver disease/pediatric end-stage liver disease scoring systems, Liver Injury Unit [LIU] using prothrombin time [PT] or international normalized ratio [INR], admission LIU using PT or INR, and Devarbhavi model) with one another.

RESULTS

Among the 41 Han Chinese patients with ALF, WD was established by demonstrating ATP7B variants in 36. In 5 others, Kayser-Fleischer rings and Coombs-negative hemolytic anemia permitted diagnosis. Three died during hospitalization and three underwent liver transplantation (LT) within 1 mo of presentation and survived (7.3% each); 35 (85.4%) survived without LT when given enteral D-penicillamine and zinc-salt therapy with or without urgent plasmapheresis. Parameters significantly correlated with mortality included encephalopathy, coagulopathy, and gamma-glutamyl transpeptidase activity, bilirubin, ammonia, and serum sodium levels. Area under the receiver operating curves varied among seven prognostic models from 0.981 to 0.748 with positive predictive values from 0.214 to 0.429.

CONCLUSION

WDALF children can survive and recover without LT when given D-penicillamine and Zn with or without plasmapheresis, even after enlisting for LT.

NBAS disease: 14 new patients, a recurrent mutation, and genotype-phenotype correlation among 24 Chinese patients

AIM

Neuroblastoma amplified sequence (NBAS)-associated disease has a wide phenotypic spectrum, including infantile liver failure syndrome type 2 (ILFS2, OMIM #616483), short stature with optic nerve atrophy and Pelger-Huët anomaly (SOPH) syndrome (OMIM #614800), and a combined phenotype overlapping ILFS2 and SOPH syndrome. The mutation spectra of NBAS and its genotype-phenotype correlation among Chinese were not clear.

METHODS

Clinical and genetic data were retrospectively collected from the medical charts of patients with biallelic NBAS mutations, as well as from Chinese patients in previously published reports.

RESULTS

Fourteen new patients were identified, including 10 novel mutations: c.648-1G>A, c.2563_c.2577+5del/p.His855_Gln859del, c.3115C>T/p.Gln1039Ter, c.3284G>A/p.Trp1095Ter, c.2570C>T/p.Ala857Val, c.6859G>T/p.Asp2287Tyr, c.1028G>A/p.Ser343Asn, c.1177_1182delinsAGATAGA/p.Val393ArgfsTer2, c.3432_3435dupCAGT/p.Ala1146GlnfsTer14, and c.680_690dupACTGTTTCAGC/p.Phe231ThrfsTer35. All 14 patients presented as fever-triggered liver injury, including nine patients that satisfied the criteria of acute liver failure (ALF) in whom c.3596G>A/p.Cys1199Tyr occurred five times. Nine patients had extrahepatic manifestations including short stature, skeletal abnormalities, intellectual disability, ophthalmic abnormalities, low levels of serum immunoglobulins, facial dysmorphism, and cardiac abnormalities. Ten other Chinese patients were collected through a review of published works. Genotype-phenotype analysis in 24 Chinese patients revealed that the percentage of ALF patients with variants in the Sec39 domain was significantly higher than that in the C-terminal (100% vs. 12.5%, P = 0.000), and the percentage of multi-organ/system involvement in patients with variants in the Sec39 domain was significantly lower than that in the C-terminal (40% vs. 100%, P = 0.0128).

CONCLUSIONS

We reported 14 new patients, 10 novel mutations, and a unique recurrent mutation. Correlation analysis indicated that the domain of missense and non-frameshift insertion/deletion mutations in NBAS protein is related to phenotype among Chinese patients.

A novel NFIA gene nonsense mutation in a Chinese patient with macrocephaly, corpus callosum hypoplasia, developmental delay, and dysmorphic features

BACKGROUND

NFIA gene (OMIM*600727) has been shown to be associated with a syndrome of central nervous system malformations (corpus callosum and ventriculomegaly) with or without urinary tract defects(BRMUTD) (OMIM#613735) with a low incidence. METHODS AND RESULTS:   We presented the clinical data of a 3-month-old Chinese infant with clinical features such as thin corpus callosum, ventriculomegaly, development delay, and dysmorphic features (macrocephaly, hypertelorism, slightly pointed chin, broad forehead, and large ears). Genomic DNA was extracted for Trio Whole Exome Sequencing. Preliminary genetic tests revealed one de novo heterozygous nonsense mutation c.220 C>T (p.Arg74Ter) of the NFIA gene (NM_005595).

CONCLUSION

Genetic DNA sequencing is a crucial method for diagnosing BRMUTD. This approach enriches the genotype and spectrum of BRMUTD syndrome and the outcome of the patient.

Glycogen storage disease type VI can progress to cirrhosis: ten Chinese patients with GSD VI and a literature review

Objectives The aim of our study is to systematically describe the genotypic and phenotypic spectrum of Glycogen storage disease type VI (GSD VI), especially in Chinses population.  Methods We retrospectively analyzed ten Chinese children diagnosed as having GSD VI confirmed by next generation sequencing in Children's Hospital of Fudan University and Jinshan Hospital of Fudan University. We described the genotypic and phenotypic spectrum of GSD VI through the clinical and genetic data we collected. Moreover, we conducted a literature review, and we compared the genotypic and phenotypic spectrum of GSD VI between Chinese population and non Chinese population.  Results For the first time, we found that four Chinese patients showed cirrhosis in liver biopsy characterized by the formation of regenerative nodules. In addition, c.772+1G>A and c.1900G>C, p.(Asp634His) were recurrent in three Chinese families and four European families respectively indicating that the genotypic spectrum of PYGL gene may vary among the population. Furthermore, we identified seven novel variants in PYGL gene.  Conclusions Our study enriched the genotypic and phenotypic spectrum of GSD VI, and provided a new clue for management of GSD VI.

Biallelic loss-of-function ZFYVE19 mutations are associated with congenital hepatic fibrosis, sclerosing cholangiopathy and high-GGT cholestasis

BACKGROUND

For many children with intrahepatic cholestasis and high-serum gamma-glutamyl transferase (GGT) activity, a genetic aetiology of hepatobiliary disease remains undefined. We sought to identify novel genes mutated in children with idiopathic high-GGT intrahepatic cholestasis, with clinical, histopathological and functional correlations.

METHODS

We assembled a cohort of 25 children with undiagnosed high-GGT cholestasis and without clinical features of biliary-tract infection or radiological features of choledochal malformation, sclerosing cholangitis or cholelithiasis. Mutations were identified through whole-exome sequencing and targeted Sanger sequencing. We reviewed histopathological findings and assessed phenotypical effects of ZFYVE19 deficiency in cultured cells by immunofluorescence microscopy.

RESULTS

Nine Han Chinese children harboured biallelic, predictedly complete loss-of-function pathogenic mutations in ZFYVE19 (c.314C>G, p.S105X; c.379C>T, p.Q127X; c.514C>T, p.R172X; c.547C>T, p.R183X; c.226A>G, p.M76V). All had portal hypertension and, at liver biopsy, histopathological features of the ductal plate malformation (DPM)/congenital hepatic fibrosis (CHF). Four children required liver transplantation for recurrent gastrointestinal haemorrhage. DPM/CHF was confirmed at hepatectomy, with sclerosing small-duct cholangitis. Immunostaining for two primary-cilium axonemal proteins found expression that was deficient intraluminally and ectopic within cholangiocyte cytoplasm. ZFYVE19 depletion in cultured cells yielded abnormalities of centriole and axoneme.

CONCLUSION

Biallelic ZFYVE19 mutations can lead to high-GGT cholestasis and DPM/CHF in vivo. In vitro, they can lead to centriolar and axonemal abnormalities. These observations indicate that mutation in ZFYVE19 results, through as yet undefined mechanisms, in a ciliopathy.

An infant presenting with extreme hypertriglyceridemia diagnosed as glycogen storage disease type Ia

Background Marked hypertriglyceridemia in infancy is extremely rare. Patients with severe hypertriglyceridemia in early life may be unmasked by a primary or secondary cause. Case presentation A female infant was born in a good condition with normal Apgar scores. No special clinical symptoms and signs had been found within the first two months of life. Poor oral intake and failure to thrive were two main clinical manifestations when she was referred to our hospital at the age of 3.5 months. The milky serum was the only one characteristic presentation. Laboratory testing showed extremely high level of triglycerides, cholesterol and lactate. Many other laboratory indexes cannot be detected because of severe hyperlipemic samples. Multi-gene panel testing for 249 genes about genetic and metabolic liver disease were performed. Gene analysis revealed a G6PC gene deficiency. The patient was a homozygote for c.248G > A, p.R83H and her parents were both the heterozygotes. The infant had been diagnosed as glycogen storage disease type Ia. Conclusions We report an infant presenting with extreme hypertriglyceridemia diagnosed as glycogen storage disease type Ia by genetic testing. The gene panel can be used to confirm the diagnosis and delineate the exact type of glycogen storage disease, which could ultimately really help to reduce unnecessary tests and invasive examinations. Serum lipid should be close monitoring in order to prevent the complications and improve the prognosis.

Novel missense mutation in VPS33B is associated with isolated low gamma-glutamyltransferase cholestasis: Attenuated, incomplete phenotype of arthrogryposis, renal dysfunction, and cholestasis syndrome

The typical phenotype of arthrogryposis, renal dysfunction, and cholestasis (ARC) syndrome involves three cardinal symptoms as the name describes, harboring biallelic mutations on VPS33B or VIPAS39. Except for ARC syndrome, low gamma-glutamyltransferase (GGT) cholestasis often implies hereditary hepatopathy of different severity; however, some remain undiagnosed. Several monogenic defects typically with multiorgan manifestations may only present liver dysfunction at times, such as DGUOK defect and AGL defect. Previously, four VPS33B mutated cases were reported without arthrogryposis, or with less severe symptoms and longer lifespan, indicating the possibility of incomplete ARC phenotype of isolated hepatopathy. So we retrospectively reviewed all patients with confirmed VPS33B/VIPARS39 defect in our center and identified three presenting isolated low-GGT cholestasis with intractable pruritus. Distinguished from others with typical ARC phenotype, these patients did not suffer the other two typical characteristics, survived much longer, and shared a novel missense VPS33B variation c.1726T>C, p.Cys576Arg, causing declined protein expression and abolished interaction with VIPAS39 in-vitro. Serum bile acid profiles of our VPS33B/VIPAS39 mutated patients revealed similar changes to primary defect of bile salt export pump, among which those with isolated cholestasis phenotype had a higher level of total secondary bile acids than that with typical ARC phenotype, indicating the partial residual function of VPS33B.

Risk factors associated with mortality in neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) and clinical implications

Background

Neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) has high prevalence in East Asia, and has been reported in other parts of the world. NICCD is also the most common form of genetic cholestasis among East Asians. There has been reports of mortalities or liver transplants associated with NICCD, but risk factors associated with poor outcome were unknown. Our objective is to report NICCD mortalities in a tertiary pediatric hepatology center, and to explore associated risk factors along with implications to clinical practice.

Method

This is a retrospective analysis of NICCD cases collected from June 2003 until January 2017 in the Children’s Hospital of Fudan University. Clinical, biochemical, and genetic data were compared between deceased cases and survivors without liver transplant.

Results

Sixty-one confirmed NICCD cases, including 52 cases in the survival group, and 9 cases in the mortality group, were included in the analysis. Mean age at referral in the mortality group was significantly higher when compared to the survival group (9.58 ± 5.03 VS 3.96 ± 3.13 months, p < 0.000). The proportion with infection in the mortality group was significantly higher than the survival group (p = 0.023). 44.4% of patients in the mortality group did not receive lactose-free and/or medium chain triglycerides enriched (LF/MCT) formula, and this percentage was significantly higher than the survival group (9.6%, p = 0.021). Mean platelet (PLT) count in the mortality group was significantly lower than the survival group (p = 0.010). Mean serum gamma-glutamyl transpeptidase (GGT), and total cholesterol (TCH) levels were significantly lower in the mortality group when compared to the survival group with p values of 0.001, and 0.019, respectively. Those who died had higher serum ammonium levels than survivors (p = 0.016). Mean level of citrulline was significantly lower in the mortality group compared to the survival group (p = 0.010). On the other hand, mean level of tyrosine was significantly higher in the mortality group than that of the survival group (p = 0.015).

Conclusion

Late referral, presence of infection, delayed treatment with LF/MCT formula, lower platelet count, lower levels of GGT, total cholesterol, blood citrulline, and higher level of blood ammonia and tyrosine, were associated with poor prognosis in NICCD.

Electronic supplementary material

The online version of this article (10.1186/s12887-018-1383-5) contains supplementary material, which is available to authorized users.

Novel Melanocortin 2 Receptor Variant in a Chinese Infant With Familial Glucocorticoid Deficiency Type 1, Case Report and Review of Literature

Familial glucocorticoid deficiency type 1 (FGD1) is an autosomal recessive disorder caused by mutations in the melanocortin 2 receptor (MC2R) gene, characterized by a low or undetectable serum cortisol level and a high adrenocorticotropic hormone (ACTH) level. Clinical manifestations include hypoglycemia, seizure, skin hyperpigmentation, hyperbilirubinemia, cholestasis, and a tall stature. Some dysmorphic features such as, a prominent forehead, hypertelorism, a broad nasal bridge, and small tapering fingers, have been reported. Children with FGD1 may have other isolated endocrine abnormalities. To date, no patient with FGD1 has been reported in mainland China. Here we report on a Chinese patient with FGD1 having a novel MC2R gene variant, a mild transverse palm crease, hypertelorism, and subtle/transient endocrine abnormalities relating to all three zones of the adrenal cortex and thyroid gland. We also reviewed cases with dysmorphic features or additional endocrine abnormalities.

UGT1A1 genotypes and unconjugated hyperbilirubinemia phenotypes in post-neonatal Chinese children: A retrospective analysis and quantitative correlation

To retrospectively analyze and quantitatively correlate UGT1A1 (bilirubin UDP- glucuronosyltransferase gene) genotypes and unconjugated hyperbilirubinemia (UCH) phenotypes among Chinese children.We retrospectively reviewed UCH patients, quantitatively analyzed genotype-phenotype correlation by comparing with healthy controls. Pfam database, SWISS-model, and Pymol were used for UGT1A1 protein domain analysis and protein modeling for assessing the effect of novel missense variants on protein structure.Seventy four cases, including 21 prolonged unconjugated hyperbilirubinemia (PUCH), 30 Gilbert syndrome (GS), 22 Crigler-Najjar syndrome type II (CNS-II), and 1 Crigler-Najjar syndrome type I (CNS-I) phenotypes were analyzed. Total of 21 variants, including 7 novel variants (c.764T>A/p.L255Q, c.1112C>T/p.T371I, c.1028C>A/p.S343X, c.1047delG/p.I350YfsX16, c.996 + 5G>C/g.6923G>C, c.287G>A/p.G96E, and c.1142G>A/p.S381N) were found. In the multiple regression model, heterozygous A(TA)7TAA, G71R/P364L, and Y486D/other mutations were significantly associated with increased risk of GS, PUCH, and CNS-II, respectively. Total allele number is significantly associated with GS and CNS-II, with each increase in total allele number, the odds ratio (OR) of having GS and CNS-II increased by 1.46 and 4.47 fold, respectively. Having only functional polymorphisms in UGT1A1 gene is associated with increased risk of PUCH, and GS with OR values of 5.67 (95% CI: 1.52-21.13), and 3.88 (95% CI: 1.02-14.78), respectively. Having only mutation is associated with significantly increased risk of having GS phenotype (OR: 34.00, 95% CI: 4.65-248.37), but not CNS-II. Polymorphism plus mutation had the strongest association with CNS-II with OR value of 64.80 (95% CI: 7.68-546.41), followed by GS (OR: 4.53, 95% CI: 1.08-19.08).We detected 7 novel variants, and quantitatively calculated risks of having specific phenotypes using genetic data. Among Chinese children, G71R and P364L is independently associated with PUCH, A(TA)7TAA is associated with GS, and Y486D or other disease-causing mutations were associated with CNS-II. Multiple alleles were associated with more severe phenotypes. Combined variant of G71R+Y486D is a common occurrence among Chinese children with UCH.

Novel methionyl-tRNA synthetase gene variants/phenotypes in interstitial lung and liver disease: A case report and review of literature

Interstitial lung and liver disease (ILLD) is caused by biallelic mutations in the methionyl-tRNA synthetase (MARS) gene. To date, no genetic changes other than missense variants were reported in the literature. Here, we report a five-month old female infant with typical ILLD (failure to thrive, developmental delay, jaundice, diffuse interstitial lung disease, hepatomegaly with severe steatosis, anemia, and thrombocytosis) showing novel phenotypes such as kidney stones, acetabular dysplasia, prolonged fever, and extreme leukocytosis. Whole exome sequencing revealed a novel truncating variant (c.2158C>T/p.Gln720Stop) together with a novel tri-nucleotide insertion (c.893_894insTCG that caused the insertion of an arginine at amino acid position 299) in the MARS gene.

A fatal case of mitochondrial DNA depletion syndrome with novel compound heterozygous variants in the deoxyguanosine kinase gene

The deoxyguanosine kinase (DGUOK) gene controls mitochondrial DNA (mtDNA) maintenance, and variation in the gene can alter or abolish the anabolism of mitochondrial deoxyribonucleotides. A Chinese female infant, whose symptoms included weight stagnation, jaundice, hypoglycemia, coagulation disorders, abnormal liver function, and multiple abnormal signals in the brain, died at about 10 months old. Genetic testing revealed a compound heterozygote of alleles c.128T>C (p.I43T) and c.313C>T (p.R105^*) of the DGUOK gene. c.128T>C (p.I43T) is a novel variant located in exon 1 (NM_080916) in the first beta sheet of DGUOK. Her mother was an allele c.313C>T (p.R105^*) heterozygote, which is located in DGUOK exon 2 (NM_080916) between the third and fourth alpha helixes. c.313C>T (p.R105^*) is predicted to result in a 173 amino acid residue truncation at the C terminus of DGUOK. There are as many as 112 infantile mtDNA depletion syndrome (MDS) cases in the literature related to DGUOK gene variants. These variants include missense mutations, nucleotide deletion, nucleotide insertion, and nucleotide duplication. Integrated data showed that mutations affected both conserved and non-conserved DGUOK amino acids and are associated with patient deaths.

Wilson disease with hepatic presentation in an eight-month-old boy

Wilson disease is an autosomal recessive disorder of copper metabolism that can cause fatal neurological and hepatic disease if not diagnosed and treated. The youngest child with normal liver function reported so far is an 8-mo-old Japanese boy with low ceruloplasmin levels, and the youngest child with elevated aminotransferase ever reported so far is a 9-mo-old Korean boy with confirmed by genetic testing. Here we report an 8-mo-old Chinese boy presented with elevated liver enzymes, and low serum ceruloplasmin level. Genetic analysis of ATP7B gene detected two heterozygous disease causing mutations (c.2621C>T/p.A874V and c.3809A>G/p.N1270S), and parental origins were determined. Persistent elevation of serum aminotransferase in this infant was normalized after zinc therapy. To our best knowledge, this is the youngest patient with elevated liver enzymes ever reported worldwide. We hope that this will raise awareness among pediatricians, leading to earlier diagnosis, timely treatment, and better clinical outcome.

JAG1 Mutation Spectrum and Origin in Chinese Children with Clinical Features of Alagille Syndrome

Alagille syndrome is an autosomal dominant disorder that results from defects in the Notch signaling pathway, which is most frequently due to JAG1 mutations. This study investigated the rate, spectrum, and origin of JAG1 mutations in 91 Chinese children presenting with at least two clinical features of Alagille syndrome (cholestasis, heart murmur, skeletal abnormalities, ocular abnormalities, characteristic facial features, and renal abnormalities). Direct sequencing and/or multiplex-ligation-dependent probe amplification were performed in these patients, and segregation analysis was performed using samples available from the parents. JAG1 disease-causing mutations were detected in 70/91 (76.9%) patients, including 29/70 (41.4%) small deletions, 6/70 (8.6%) small insertions, 16/70 (22.9%) nonsense mutations, 8/70 (11.4%) splice-site mutations, 6/70 (9.4%) missense mutations, and 5/70 (7.1%) gross deletions. Of the mutations detected, 45/62 (72.6%) were novel, and almost all were unique, with the exception of c.439C>T, c.439+1G>A, c.703C>T, c.1382_1383delAC, c.2698C>T, and c.2990C>A, which were detected in two cases each; three cases exhibited entire gene deletions. A majority (69.2%) of the point and frameshift mutations could be detected by the sequencing of eleven exons (exons 3, 5, 6, 11, 14, 16, 18, 21, and 23-25). The mutation detection rate was 50.0% (10/20) in atypical cases that only presented with two or three clinical features of Alagille syndrome. Segregation analysis revealed that 81.1% (30/37) of these mutations were de novo. In conclusion, JAG1 mutations are present in the majority of Chinese pediatric patients with clinical features of Alagille syndrome, and the mutations concentrate on different exons from other reports. Genetic study is important for the diagnosis of atypical Alagille syndrome in Chinese patients.