Yuan-Zong Song’s research while affiliated with University of Jinan and other places

Deficiency of citrin, the liver-type aspartate-glutamate carrier, arises from biallelic mutations of the gene SLC25A13. Although citrin deficiency (CD) is associated with higher risk of hepatocellular carcinoma (HCC) in adult patients, this association remains inconclusive in pediatric cases. The patient in this paper had been diagnosed to have CD by SLC25A13 analysis at the age 10 months, and then in response to dietary therapy, her prolonged jaundice and marked hepatosplenomegaly resolved gradually. However, she was referred to the hospital once again due to recurrent abdominal distention for 2 weeks at her age 4 years and 9 months, when prominently enlarged liver and spleen were palpated, along with a strikingly elevated serum alpha-fetoprotein (AFP) level of 27605 ng/mL as well as a large mass in the right liver lobe and a suspected tumor thrombus within the portal vein on enhanced computed tomography. After 4 rounds of adjuvant chemotherapy, right hepatic lobectomy and portal venous embolectomy were performed at her age 5 years and 3 months, and metastatic hepatoblastoma was confirmed by histopathological analysis. Afterwards, the patient underwent 5 additional cycles of chemotherapy and her condition remained stable for 7 months after surgery. Unfortunately, hepatoblastoma recurred in the left lobe at the age 5 years and 10 months, which progressed rapidly into liver failure, and led to death at the age 6 years and 1 month. As far as we know, this is the the first case of hepatoblastoma in a patient with CD, raising the possibility of an association between these two conditions.

Background Progressive familial intrahepatic cholestasis type 3 (PFIC3) is an autosomal recessive disease caused by pathogenic variants of the gene ABCB4 . This study aimed to investigate the ABCB4 genotypic and the clinical phenotypic features of PFIC3 patients. Methods The clinical and molecular genetic data of 13 new pediatric patients with PFIC3 as well as 82 reported ones in the PubMed and CNKI databases were collected and analyzed. Results The 13 new PFIC3 patients included six females and seven males, and the main presentations were hepatomegaly, splenomegaly, jaundice, and pruritus, as well as increased levels of gamma-glutamyl transpeptidase (GGT). Fourteen new ABCB4 variants were detected, including eight diagnosed to be likely-pathogenic and six, pathogenic. Among all the 95 PFIC3 cases, hepatomegaly was observed in 85.3% (81/95), pruritus in 67.4% (64/95), splenomegaly in 52.6% (50/95), jaundice in 48.4% (46/95), portal hypertension in 34.7% (33/95) and GGT elevation in 100% (88/88) of the patients. Positive responses at varied degrees to oral ursodeoxycholic acid (UDCA) treatment were observed in 66.1% (39/59) of the patients, among whom 38.5% (15/39) fully recovered in terms of the laboratory changes. Although the condition remained stable in 53 patients (58.9%, 53/90), the clinical outcomes were not promising in the rest 37 cases (41.1%, 37/90), including 7 died, 27 having undergone while another 3 waiting for liver transplantation. A total of 96 ABCB4 variants were detected in the 95 patients. PFIC3 patients with biallelic null variants exhibited earlier onset ages [10.5 (2, 18) vs. 19 (8, 60) months, p = 0.007], lower UDCA response rate [18.2% (2/11) vs. 77.1% (37/48), p = 0.001], and more unpromising clinical outcomes [80% (12/15) vs. 33.3% (25/75), p = 0.001], compared with those with non-biallelic null variants. Conclusions PFIC3 presented with hepatomegaly, pruritus, splenomegaly and jaundice with increased serum GGT level as a biochemistry hallmark. Although varying degrees of improvement in response to UDCA therapy were observed, 41.1% of PFIC3 patients exhibited unfavorable prognosis. ABCB4 genotypes of biallelic null variants were associated with severer PFIC3 phenotypes. Moreover, the 14 novel variants in this study expanded the ABCB4 mutation spectrum, and provided novel molecular biomarkers for diagnosis of PFIC3 patients.

Background and aims: Although the significance of primary congenital hypothyroidism (CH) is supported by an increasing amount of evidence, the clinical and genetic characteristics of this condition are still poorly understood. This study aimed to explore the underlying genetic etiologies in a cohort of primary CH patients. Subjects and methods: The clinical data of 33 patients with primary CH were collected and analyzed via a cross-sectional study. Genetic analysis was performed by high-throughput sequencing and Sanger verification, and the pathogenicity of the novel missense variants was predicted using a variety of comprehensive bioinformatic tools. Results: Among the 33 patients, 22 (22/33, 66.7%) harbored pathogenic variants in the causative genes of thyroid dysgenesis or dyshormonogenesis, with DUOX2 (15/33, 45.5%) topping the list, followed by TG, TPO, DUOXA2 and PAX8. Four novel genetic variants were detected, including a pathogenic frameshift and three likely pathogenic missense variants. Positive neonatal screening for TSH, neonatal jaundice and abnormal thyroid morphology were the main positive findings among all cases. Although 31 of the total 33 CH patients exhibited normal anthropometric and social performance, the other 2 had poor prognosis in this study. Conclusions: This study reported 33 new CH patients bearing four novel genetic variants, which enriched the variant spectrum of CH genes. In this cohort, genetic factors causing thyroid dyshormonogenesis were the main etiologies of CH development. Most patients exhibited a favorable prognosis; however, systematic management remains a challenge in achieving improved clinical outcomes for CH patients.

Background Infantile hypotonia with psychomotor retardation and characteristic facies type 3(IHPRF3) (OMIM #616,900) is an autosomal recessive disorder caused by biallelic pathogenic variants of the TBCK gene, and to date, this disease was reported rather limitedly in number and all described cases were Caucasians. Case presentation This paper reported the clinical and genetic features of a Chinese patient with IHPRF3. The patient was a 15-month-old male with global developmental delay, profound hypotonia, and typical facial dysmorphic features including mildly coarse facial appearance, hypertelorism, tented upper lip, exaggerated Cupid’s bow, macroglossia and arched eyebrows. Magnetic Resonance Imaging (MRI) analysis of the brain revealed slightly widened bilateral ventricles and subarachnoid space. On genetic analysis, the patient was homozygous for a novel TBCK variant c.247C > T(p.Arg83Ter). The parents were both carriers without any positive symptoms or signs. With an extremely low frequency (0.0000082) in Exome Aggregation Consortium, the variant has not been reported in any other databases or official literatures, and was diagnosed to be pathogenic according to the American College of Medical Genetics and Genomics(ACMG) standards and guidelines. Neurorehabilitation training did not work well and the long-term prognosis remained to be observed. Conclusions This study reported the clinical and molecular features of the first non-Caucasian patient with IHPRF3 arising from a novel homozygous TBCK mutation, which provided a novel molecular marker for the definite diagnosis of IHPRF3 patients and for its genetic counseling and prenatal diagnosis in the affected families.

Na⁺-taurocholate cotransporting polypeptide deficiency (NTCPD) is an autosomal recessive disorder arising from biallelic SLC10A1 mutations. As a newly-described inborn error of bile acid metabolism, the epidemiology of this condition remains largely unclear in Chinese population so far. In this study, a total of 2,828 peripheral blood samples were collected from 12 cities in Guangdong, a province with the largest population in China, and the four prevalent SLC10A1 variants c.800C > T (p.Ser267Phe), c.263T > C (p.Ile88Thr), c.595A > C (p.Ser199Arg) and c.665T > C (p.Leu222Ser) were screened for by using polymerase chain reaction (PCR)- restriction fragment length polymorphism (RFLP). As a result, 663 mutated SLC10A1 alleles were detected, and the mutated allele frequency was calculated to be 11.72% (663/5,656), with a carrier frequency 20.69% (1/5) and a theoretical morbidity rate 1.37% (1/73) of NTCPD in Guangdong province. The variant c.800C > T (p.Ser267Phe) exhibited highest allele frequency among the four prevalent variants (χ² = 1501.27, p < 0.0001) as well as higher allele frequency in the peripheral region than that within the Pearl River Delta (χ² = 4.834, p < 0.05). The results suggested that NTCPD might be a disorder rather common in Guangdong province. The findings depicted the molecular epidemiologic features of NTCPD, providing preliminary but significant laboratory evidences for the subsequent NTCPD diagnosis and management in Guangdong population.

Na⁺-taurocholate cotransporting polypeptide deficiency (NTCPD) is a newly described disorder arising from biallelic mutations of the SLC10A1 gene. Due to a lack of compelling evidence from case-control studies, its genotypic and phenotypic features remain open for in-depth investigation. This study aimed to explore the genotypic and clinical phenotypic characteristics of pediatric patients with NTCPD. The SLC10A1 genotypes of all NTCPD patients were confirmed by screening for the prevalent variant c.800C>T and Sanger sequencing when necessary. The clinical presentations and laboratory changes were collected, reviewed, and analyzed, and then qualitatively and quantitatively compared with the relevant controls. A total of 113 pediatric NTCPD patients were diagnosed while c.374dupG and c.682_683delCT were detected as two novel pathogenic mutations. Hypercholanemia was observed in 99.12% of the patients. Indirect hyperbilirubinemia in affected neonates exhibited higher positive rates in comparison to controls. Moreover, transient cholestatic jaundice, elevated liver enzymes, and 25-hydroxyvitamin D (Vit D) deficiency during early infancy were more commonly observed in patients than in controls. All NTCPD patients exhibited favorable clinical outcomes as a result of symptomatic and supportive treatment. The findings enriched the SLC10A1 mutation spectrum and provided comprehensive insights into the phenotypic characteristics of NTCPD. NTCPD should be considered and SLC10A1 gene should be analyzed in patients with above age-dependent clinical features. Furthermore, over investigation and intervention should be avoided in the management of NTCPD patients.

Background: Citrin deficiency (CD) is an autosomal recessive disease resulting from biallelic mutations of the SLC25A13 gene. This study aimed to investigate the molecular epidemiological features of CD in the Guangdong and Shaanxi provinces of China. Methods: A total of 3,409 peripheral blood samples from Guangdong and 2,746 such samples from Shaanxi province were collected. Four prevalent SLC25A13 mutations NG_012247.2 (NM_014251.3): c.852_855del, c.1638_1660dup, c.615+5G>A, and c.1751-5_1751-4ins(2684) were screened by using the conventional polymerase chain reaction (PCR)/PCR-restriction fragment length polymorphism and newly-developed multiplex PCR methods, respectively. The mutated SLC25A13 allele frequencies, carrier frequencies, and CD morbidity rates were calculated and then compared with the Chi-square and Fisher's exact tests. Results: The mutations were detected in 68 out of 6,818 SLC25A13 alleles in Guangdong and 29 out of 5,492 alleles in the Shaanxi population. The carrier frequencies were subsequently calculated to be 1/51 and 1/95, while the CD morbidity rates were 1/10,053 and 1/35,865, in the 2 populations, respectively. When compared with the Shaanxi population, Guangdong exhibited a higher frequency of mutated SLC25A13 allele (68/6,818 vs. 29/5,492, χ2=8.570, P=0.003) in general, with higher c.852_855del (54/6,818 vs. 13/5,492, χ2=17.328, P=0.000) but lower c.1751-5_1751 -4ins(2684) (2/6,818 vs. 9/5,492, P=0.015) allele frequencies. The distribution of c.615+5G>A and c.1638_1660dup between the 2 provinces, as well as all 4 prevalent mutations among different geographic regions within the 2 provinces, did not differed significantly. Conclusions: Our findings depicted the CD molecular epidemiological features in Guangdong and Shaanxi populations, providing preliminary but significant laboratory evidences for the subsequent CD diagnosis and management in the 2 provinces of mainland China.

Neonatal Intrahepatic Cholestasis caused by Citrin Deficiency (NICCD) is an autosomal recessive disease resulting from biallelic SLC25A13 mutations, and its diagnosis relies on genetic analysis. This study aimed to characterize the pathogenicity of 2 novel splice-site variants of SLC25A13 gene. Two patients (C0476 and C0556) suspected to have NICCD, their family members and 9 healthy volunteers were recruited as the research subjects. The SLC25A13 genotypes NG_012247.2(NM_014251.3): c.[852_855del];[69+5G>A] in patient C0476 and c.[1453-1G>A]; [1751-5_1751-4ins(2684)] in patient C0556 were identified by means of polymerase chain reaction, long and accurate polymerase chain reaction, as well as Sanger sequencing. The 2 splice-site variants were absent in control databases and predicted to be pathogenic by computational analysis. The alternative splice variants in monocyte-derived macrophages from patient C0476 demonstrated exon 2 skipping [r.16_69del; p.(Val6_Lys23del)] in vivo, while minigene analysis revealed both exon 2-skipping and retained products from c.69+5G>A in vitro. In the patient C0556, an aberrant transcript [r.1453del; p.(Gly485Valfs*22)] resulting from c.1453-1G>A was detected on minigene splicing study. Thus, c.69+5G>A and c.1453-1G>A were both proved to be pathogenic. The 2 novel splice-site variants expanded the SLC25A13 mutation spectrum and provided reliable molecular markers for the definite diagnosis and genetic counseling of NICCD in the affected families.

Pearson syndrome (PS), also known as Pearson marrow-pancreas syndrome, is a rare, multi-systemic disorder caused by large-scale deletion of mitochondrial DNA (mtDNA) ranging from 2.3 kb to 9 kb, with 4,977 bp in length as the most common variant. This paper reported a novel mtDNA deletion of 4,734 bp in size, spanning from nucleotide 11,220 to 15,953. The infant suffered from chronic hepatomegaly, liver dysfunction, anemia and lactic acidosis over 1 year. Evidences of any infections were negative. Bone marrow aspiration and whole exome sequencing covering nearly 20,000 nucleus genes were performed when aged 3.3 and 6 months, respectively, but no genetic cause was identified. However, at his age 13 months, multiplex ligation-dependent probe amplification assay of the mtDNA in the patient detected a large deletion of 4,734 bp in size spanning the mitochondrial genes MTND4, MTTH, MTTS2, MTTL2, MTND5, MTND6, MTTE, MTCYB and MTTT which were functionally crucial for the intact oxidative phosphorylation pathway and adenosine triphosphate production, and PS was thus definitely diagnosed. This large deletion was negative in his parents and elder brother. Oral ursodeoxycholic acid, fat-soluble vitamins and blood transfusions were administrated, his clinical and laboratory presentations remained stable so far, but the long-term prognosis needed to be followed up. These findings enriched the variant spectrum of mtDNA, and demonstrated the importance of considering mitochondrial disorder in patient with intractable anemia, liver dysfunction and lactic acidosis as well as the significance of appropriate choosing of relevant genetic tools in the etiology diagnosis of such patients.