Multisystemic Manifestations in Rare Diseases: The Experience of Dyskeratosis Congenita

TERT de novo mutation-associated dyskeratosis congenita and porto-sinusoidal vascular disease: a case report

BACKGROUND

Dyskeratosis congenita is a rare genetic disease due to telomere biology disorder and characterized by heterogeneous clinical manifestations and severe complications. "Porto-sinusoidal vascular disease" has been recently proposed, according to new diagnostic criteria, to replace the term "idiopathic non-cirrhotic portal hypertension." TERT plays an important role in telomeric DNA repair and replication. A TERT c.2286 + 1G/A mutation in a splicing consensus site was identified in a patient with pulmonary fibrosis. Recently, a pathogenic de novo TERT c.280A > T variant was associated with diffuse lung disease in an infant.

CASE PRESENTATION

A 16-year-old Han male patient experienced unexplained black stool for 7 days, accompanied by dizziness and fatigue. On examination, there were mesh pigmentations on the exposed areas of the skin on both hands and feet. Laboratory testing revealed moderate hemorrhagic anemia and mild elevation of alanine aminotransferase. A computed tomography scan showed portal hypertension, esophageal and gastric varices, and splenomegaly. The liver stiffness measurement by FibroScan was 6.0 kPa. Liver biopsy revealed typical features of porto-sinusoidal vascular disease. Whole exome sequencing identified a heterozygous TERT c.2286 + 1G > A de novo mutation and quantitative polymerase chain reaction revealed very short telomeres (less than the first percentile for his age). The patient was diagnosed as TERT de novo mutation-related dyskeratosis congenita and porto-sinusoidal vascular disease. He underwent esophageal and gastric variceal ligation treatment and received a carvedilol tablet (12.5 mg) every morning. After 6 months, he has moderate iron deficiency anemia and has started receiving polysaccharide iron complex therapy.

CONCLUSION

When discovering reticular rash and unknown portal hypertension, it is necessary to perform whole exome sequencing and chromosome length testing to clarify the possibility of dyskeratosis congenita/telomere biology disorder with porto-sinusoidal vascular disease.

Characteristic phenotypes of ADH5/ALDH2 deficiency during childhood

ADH5/ALDH2 deficiency is a rare inherited syndrome characterized by short stature, microcephaly, delayed mental development, and hematopoietic dysfunction and has recently been proposed as a disease paradigm. Acute and severe presentations include aplastic anemia, myelodysplastic syndrome, or leukemia, requiring bone marrow transplantation during childhood. Conversely, non-hematological manifestations may exhibit a prolonged and nonspecific clinical trajectory, with growth failure and developmental delay, most of which are often overlooked, particularly in patients with milder symptoms. Here, we describe the clinical course of a girl with a wide spectrum of clinical presentations, including nonspecific hematopoietic disorders, growth retardation, mild developmental delay, amblyopia, hemophagocytic lymphohistiocytosis, and verruca vulgaris, culminating in a genetic diagnosis of AMeD syndrome at 12 years of age. We also summarized the clinical manifestations of previously reported cases of AMeD syndrome. Cumulatively, 13 females and 5 males have been documented, with a cardinal triad of symptoms, aplastic anemia, short stature, and intellectual disability. Additional characteristic observations included pigmentary deposition in approximately half of the cases and skeletal difficulties in one-quarter. We propose that early diagnosis of patients who exhibit relatively mild phenotypes of skin or skeletal lesions is important for managing and improving the quality of life of patients with AMeD syndrome.

Research progress of RNA pseudouridine modification in nervous system

Recent advances of pseudouridine (Ψ, 5-ribosyluracil) modification highlight its crucial role as a post-transcriptional regulator in gene expression and its impact on various RNA processes. Ψ synthase (PUS), a category of RNA-modifying enzymes, orchestrates the pseudouridylation reaction. It can specifically recognize conserved sequences or structural motifs within substrates, thereby regulating the biological function of various RNA molecules accurately. Our comprehensive review underscored the close association of PUS1, PUS3, PUS7, PUS10, and dyskerin PUS1 with various nervous system disorders, including neurodevelopmental disorders, nervous system tumors, mitochondrial myopathy, lactic acidosis and sideroblastic anaemia (MLASA) syndrome, peripheral nervous system disorders, and type II myotonic dystrophy. In light of these findings, this study elucidated how Ψ strengthened RNA structures and contributed to RNA function, thereby providing valuable insights into the intricate molecular mechanisms underlying nervous system diseases. However, the detailed effects and mechanisms of PUS on neuron remain elusive. This lack of mechanistic understanding poses a substantial obstacle to the development of therapeutic approaches for various neurological disorders based on Ψ modification.

Presumptive Cytomegalovirus Retinitis as a Complication of Dyskeratosis Congenita: A Case Report

Introduction

Dyskeratosis congenita is a rare genetic disorder characterized by abnormalities of the skin, nails, and oral mucosa. Retinal involvement in this condition is uncommon. Here, we present a case of a young male patient diagnosed with presumptive cytomegalovirus retinitis, ultimately found to be concomitant with dyskeratosis congenita.

Case Presentation

A non-HIV-infected young male with recurrent infections, including aspergillus pneumonia and pneumocystis pneumonia, presented with presumptive cytomegalovirus retinitis in both eyes. Systemic manifestations included cutaneous hyperpigmentation, nail dystrophy, and oral mucosal leukoplakia. Genetic testing revealed a mutation in the DKC1 gene. The final diagnosis was dyskeratosis congenita complicated by presumptive cytomegalovirus retinitis.

Conclusion

Cytomegalovirus retinitis can serve as an ocular complication of dyskeratosis congenita. When a patient presents with cytomegalovirus retinitis, a comprehensive systematic examination should be conducted as it indicates severe immunodeficiency.

[Progeroid syndromes : Aging, skin aging, and mechanisms of progeroid syndromes]

Progeroid syndromes (PSs) are characterized by the premature onset of age-related pathologies. PSs display a wide range of heterogeneous pathological symptoms that also manifest during natural aging, including vision and hearing loss, atrophy, hair loss, progressive neurodegeneration, and cardiovascular defects. Recent advances in molecular pathology have led to a better understanding of the underlying mechanisms of these diseases. The genetic mutations underlying PSs are functionally linked to genome maintenance and repair, supporting the causative role of DNA damage accumulation in aging. While some of those genes encode proteins with a direct involvement in a DNA repair machinery, such as nucleotide excision repair (NER), others destabilize the genome by compromising the stability of the nuclear envelope, when lamin A is dysfunctional in Hutchinson-Gilford progeria syndrome (HGPS) or regulate the DNA damage response (DDR) such as the ataxia telangiectasia-mutated (ATM) gene. Understanding the molecular pathology of progeroid diseases is crucial in developing potential treatments to manage and prevent the onset of symptoms. This knowledge provides insight into the underlying mechanisms of premature aging and could lead to improved quality of life for individuals affected by progeroid diseases.

Telomere biology: from disorders to hematological diseases

Variations in the length of telomeres and pathogenic variants involved in telomere length maintenance have been correlated with several human diseases. Recent breakthroughs in telomere biology knowledge have contributed to the identification of illnesses named "telomeropathies" and revealed an association between telomere length and disease outcome. This review emphasizes the biology and physiology aspects of telomeres and describes prototype diseases in which telomeres are implicated in their pathophysiology. We also provide information on the role of telomeres in hematological diseases ranging from bone marrow failure syndromes to acute and chronic leukemias.

Case report: A novel mutation in RTEL1 gene in dyskeratosis congenita

Dyskeratosis congenita (DKC), also known as Zinsser-Cole-Engman syndrome, is a telomeropathy typically presenting as a triad of leukoplakia, nail dystrophy, and reticular hyperpigmentation. Reported genetic mutations linked to DKC include DKC1, TINF2, TERC, TERT, C16orf57, NOLA2, NOLA3, WRAP53/TCAB1, and RTEL1. Homozygous, compound heterozygous, and heterozygous mutations in RTEL1 (RTEL1, regulator of telomere elongation helicase 1) gene on chromosome 20q13 are known to cause autosomal dominant as well as recessive DKC. Pathogenic variants of RTEL1 gene in DKC patients include c.2288G>T (p. Gly763Val), c.3791G>A (p. Arg1264His), and RTEL p. Arg981Trp. We report a novel homozygous variant of RTEL1, transcript ID: ENST00000360203.11, exon 24, c.2060C>T (p.Ala687Val), in a patient of DKC presenting with leukoplakia, dystrophic nails, reticulate pigmentation, and positive family history of a similar phenotype. The novel variant, reported as a variant of uncertain significance, may therefore be considered diagnostic for DKC in a Pakistani population.

Early-life liver cirrhosis and variable clinical presentation in telomere disease

AIM

Telomeres are DNA sequences of tandem TTAGGG repeats that protect chromosome ends from degradation and instability. Constitutional loss-of-function telomerase mutations result in rapid telomere shortening, premature senescence and cell death. Liver cirrhosis is rare and has only been reported in adults. We present five family members of Bedouin-Muslim origin, all of which carry the same mutation, and yet demonstrate an extremely variable phenotypical presentation, including liver cirrhosis during early childhood.

METHODS

A multidisciplinary long-term follow-up of two healthy and three affected patients was analysed. The mutation (r.95G>C) was identified in all patients using Sanger sequencing. Telomere length samples were obtained and analysed.

RESULTS

Clinical phenotypes were extremely variable, including age at first symptoms, organ involvement, disease severity and patient prognosis. The most prominent clinical phenotype is liver involvement, including end-stage liver disease early in life, which affects three members of the family. Affected patients had markedly shorter telomeres.

CONCLUSION

We describe an unusual presentation of early liver failure in telomere disease patients. Little, if any, is known about the association between the genotype and phenotype among children with telomere disease and whether the mutation we have described (r.95G>C) is predisposed to early severe hepatic involvement.

The role of liver transplantation in the care of primary hepatic vascular tumours in children

Liver transplantation (LT) is the standard of care for many liver conditions, such as end-stage liver diseases, inherited metabolic disorders, and primary liver malignancies. In the latter group, indications of LT for hepatoblastoma and hepatocellular carcinoma evolved and are currently available for many non-resectable cases. However, selection criteria apply, as the absence of active metastases. Evidence of good long-term outcomes has validated the LT approach for managing these malignancies in the context of specialist and multidisciplinary approach. Nevertheless, LT's role in treating primary vascular tumours of the liver in children, both benign and malignant, remains somewhat controversial. The rarity of the different diseases and the heterogeneity of pathological definitions contribute to the controversy and make evaluating the benefit/risk ratio and outcomes quite difficult. In this narrative review, we give an overview of primary vascular tumours of the liver in children, the possible indications and the outcomes of LT.

Exploring deep learning methods for recognizing rare diseases and their clinical manifestations from texts

BACKGROUND AND OBJECTIVE

Although rare diseases are characterized by low prevalence, approximately 400 million people are affected by a rare disease. The early and accurate diagnosis of these conditions is a major challenge for general practitioners, who do not have enough knowledge to identify them. In addition to this, rare diseases usually show a wide variety of manifestations, which might make the diagnosis even more difficult. A delayed diagnosis can negatively affect the patient's life. Therefore, there is an urgent need to increase the scientific and medical knowledge about rare diseases. Natural Language Processing (NLP) and Deep Learning can help to extract relevant information about rare diseases to facilitate their diagnosis and treatments.

METHODS

The paper explores several deep learning techniques such as Bidirectional Long Short Term Memory (BiLSTM) networks or deep contextualized word representations based on Bidirectional Encoder Representations from Transformers (BERT) to recognize rare diseases and their clinical manifestations (signs and symptoms).

RESULTS

BioBERT, a domain-specific language representation based on BERT and trained on biomedical corpora, obtains the best results with an F1 of 85.2% for rare diseases. Since many signs are usually described by complex noun phrases that involve the use of use of overlapped, nested and discontinuous entities, the model provides lower results with an F1 of 57.2%.

CONCLUSIONS

While our results are promising, there is still much room for improvement, especially with respect to the identification of clinical manifestations (signs and symptoms).