Fanconi anemia, dyskeratosis congenita, and WT syndrome

Lateral thinking in syndromic congenital cardiovascular disease

Syndromic birth defects are rare diseases that can present with seemingly pleiotropic comorbidities. Prime examples are rare congenital heart and cardiovascular anomalies that can be accompanied by forelimb defects, kidney disorders and more. Whether such multi-organ defects share a developmental link remains a key question with relevance to the diagnosis, therapeutic intervention and long-term care of affected patients. The heart, endothelial and blood lineages develop together from the lateral plate mesoderm (LPM), which also harbors the progenitor cells for limb connective tissue, kidneys, mesothelia and smooth muscle. This developmental plasticity of the LPM, which founds on multi-lineage progenitor cells and shared transcription factor expression across different descendant lineages, has the potential to explain the seemingly disparate syndromic defects in rare congenital diseases. Combining patient genome-sequencing data with model organism studies has already provided a wealth of insights into complex LPM-associated birth defects, such as heart-hand syndromes. Here, we summarize developmental and known disease-causing mechanisms in early LPM patterning, address how defects in these processes drive multi-organ comorbidities, and outline how several cardiovascular and hematopoietic birth defects with complex comorbidities may be LPM-associated diseases. We also discuss strategies to integrate patient sequencing, data-aggregating resources and model organism studies to mechanistically decode congenital defects, including potentially LPM-associated orphan diseases. Eventually, linking complex congenital phenotypes to a common LPM origin provides a framework to discover developmental mechanisms and to anticipate comorbidities in congenital diseases affecting the cardiovascular system and beyond.

Fanconi anemia and dyskeratosis congenita/telomere biology disorders: Two inherited bone marrow failure syndromes with genomic instability

Inherited bone marrow failure syndromes (IBMFS) are a complex and heterogeneous group of genetic diseases. To date, at least 13 IBMFS have been characterized. Their pathophysiology is associated with germline pathogenic variants in genes that affect hematopoiesis. A couple of these diseases also have genomic instability, Fanconi anemia due to DNA damage repair deficiency and dyskeratosis congenita/telomere biology disorders as a result of an alteration in telomere maintenance. Patients can have extramedullary manifestations, including cancer and functional or structural physical abnormalities. Furthermore, the phenotypic spectrum varies from cryptic features to patients with significantly evident manifestations. These diseases require a high index of suspicion and should be considered in any patient with abnormal hematopoiesis, even if extramedullary manifestations are not evident. This review describes the disrupted cellular processes that lead to the affected maintenance of the genome structure, contrasting the dysmorphological and oncological phenotypes of Fanconi anemia and dyskeratosis congenita/telomere biology disorders. Through a dysmorphological analysis, we describe the phenotypic features that allow to make the differential diagnosis and the early identification of patients, even before the onset of hematological or oncological manifestations. From the oncological perspective, we analyzed the spectrum and risks of cancers in patients and carriers.

Ocular manifestations and visual functions in patients with Fanconi anaemia

PURPOSE

Fanconi anaemia (FA) is a multisystemic disorder with ocular implications. This study aims to describe visual function, ocular characteristics and visual processing skills in patients with FA after haematopoietic stem cell transplantation.

METHODS

Ten patients with FA, ages 8-17 years, underwent ophthalmological examinations, corneal, periocular and fundus photography, visual evoked potentials (VEPs), visual fields and ocular motor and visual processing information tests.

RESULTS

Best-corrected decimal visual acuity was ≥0.65 in all 20 eyes. Microcornea was present in 18 of 18 eyes, short axial lengths in six of six eyes, steep corneal curvatures in four of six eyes, ptosis in 14 of 16 eyes, short palpebral fissures in 15 of 16 eyes and hypotelorism in three of seven patients. Optic disc areas were smaller in patients with FA compared to controls (p = 0.0003 right, p = 0.0003 left eye). Visual fields were abnormal in 4 of 18 eyes, while VEP was abnormal in 1 of 20 eyes. Eight patients had ocular motor dysfunction, while nine of 10 patients showed delay in visual processing skills.

CONCLUSION

Patients with FA can present with microcornea, microphthalmia, ptosis, steep corneal curvatures, small optic discs, ptosis and delay in visual processing skills. Detailed ophthalmological and visual processing skills assessments and developmental investigations are important to detect impairments and facilitate appropriate support.

Dyskeratosis Congenita: a historical perspective

"Dyskeratosis Congenita (DC) also known as Zinsser-Engman-Cole syndrome is a rare multi-system bone marrow failure syndrome characterised by mucocutaneous abnormalities and an increased predisposition to cancer". This is a common definition of DC but how did this definition arise? The aim of this review is to follow the development of DC and associated diseases from its first reported description in the early 20th century to the current understanding of the genes involved and its pathophysiology in 2007 in a chronological order. Although this review is not intended to be an exhaustive citation of the literature available it does provide a summary of the key developments, citing particularly the earlier reports of each development.

Dyskeratosis congenita: delay in diagnosis and successful treatment of pancytopenia by bone marrow transplantation

Dyskeratosis congenita is an inherited disorder characterized by nail dystrophy, skin pigmentary changes, mucosal leukoplakia, pancytopenia and an increased incidence of malignancy. Because of a widely held view that the outcome of bone marrow transplantation in dyskeratosis congenita is poor, this treatment option is sometimes not considered when pancytopenia develops. We present a child currently doing well 3 years after bone marrow transplantation, and review the literature.