[Genetic analysis of a child with gastrointestinal hemorrhage and Cerebroretinal microangiopathy with calcifications and cysts and a literature review].

Objective: To explore the clinical characteristics and genetic cause of a child with gastrointestinal hemorrhage and Cerebroretinal microangiopathy with calcifications and cysts (CRMCC) and to review the literature.

Methods: Clinical data of a child with gastrointestinal hemorrhage with CRMCC admitted to the Hepatology Department of Hunan Children's Hospital in September 2019 were collected, and peripheral blood DNA of the child and his parents were analyzed by whole exome sequencing. Candidate variants were validated by Sanger sequencing, followed by bioinformatics analysis, American College of Medical Genetics and Genomics (ACMG) Standards and Guidelines for the Interpretation of Sequence Variants pathogenicity classification, and protein structure prediction. A literature search with "Coats Plus syndrome" or "Cerebroretinal microangiopathy with calcifications and cysts" as keywords was conducted at PubMed, China National Knowledge Infrastructure and Wanfang databases to include recently published studies (up to December 2023). This study has been approved by the Ethics Committee of Hunan Children's Hospital (Ethics No. KY2020-07). Informed consent for clinical research was obtained from the guardian of the child.

Results: The proband was a 10-year-10-month-old boy. The clinical manifestations were intrauterine and postnatal growth retardation, gastrointestinal hemorrhage, liver fibrosis, panhemopenia, bilateral exudative retinopathy, intracranial lesions and facial pigmentation. WES and Sanger sequencing revealed two novel heterozygous variants in the CTC1 gene: c.787G>A (p.Val263Met) in exon 5 and c.2930C>G (p.Ser977Cys) in exon 17, which were inherited from his mother and father, respectively. According to ACMG pathogenicity classification, both missense variants were classified as variants of uncertain significance (VUS). Protein structure prediction showed the absence of LIG_SH3_3 motif and LIG_SH3_3 motif, and the p.Ser977Cys mutation may affect the binding between CST (CTC1-STN1-TEN) complex and DNA strand. The child had continued to experience recurrent gastrointestinal bleeding episodes despite propranolol treatment, but the condition was controlled after liver transplantation. According to the predefined literature search strategy of this study, a total of 10 relevant articles on pediatric CRMCC patients were retrieved, involving 11 children with gastrointestinal bleeding. Pharmacological and endoscopic therapies play a certain role in the management of CRMCC children complicated with gastrointestinal bleeding.

Conclusion: The CTC1 gene c.787G>A and c.2930C>G variants probably underlay CRMCC in this child. This study has broadened the variation spectrum of CTC1-related diseases and provided a basis for genetic counseling. Liver transplantation may be an important treatment for gastrointestinal hemorrhage in children who do not respond well to medication and endoscopic therapy.