Genetic Predisposition to Vaccine-Induced Immune Thrombotic Thrombocytopenia: is there a Family Link?

Background: Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare life-threatening thrombotic reaction to COVID-19 vaccines. Case description: Two young male first cousins, with a family history of idiopathic thrombocytopenic purpura, developed VITT after the Ad26.COV2.S vaccine. Both had a favourable clinical and analytical outcome. We investigated the genetic factors that could be associated with a genetic predisposition to VITT. Conclusions: There are no published cases where the VITT patients were relatives. The genetic study did not reveal any likely pathogenic variants, although the prevalent polymorphism c.497A>G (p.(His166Arg)) in the FCGR2A gene was found in a homozygous state. More studies are required to better understand VITT's pathophysiology and any underlying genetic predispositions. LEARNING POINTS: Vaccine-induced immune thrombotic thrombocytopenia (VITT), a rare but life-threatening disease, emerged with COVID-19 vaccines.The genetic analyses revealed the FCGR2A gene in a homozygous state.These cases may raise new questions about a family predisposition to VITT.

Variants in the new E1' cryptic exon of the VHL gene associated with congenital erythrocytosis-Description of three cases.

Congenital erythrocytosis (CE) represents a rare and heterogeneous group of hereditary disorders. The molecular basis of VHL gene mutations related to CE. Recently, Lenglet et al. reported a discovery of a novel cryptic exon in the VHL gene. Mutations in the first intronic region resulting in the creation of a cryptic exon termed E1' were found in seven families with CE and one family with VHL disease. We report three patients with prolonged CE with the aetiology being clarified several years later by sequencing of intronic region 1 of the VHL gene. This work addresses the first cases reported at the clinical level of VHL-associated CE due to the E1' cryptic exon.

Vaccine-Induced Thrombotic Thrombocytopenia: A Case Report.

While the number of people who have been vaccinated against coronavirus disease 2019 (COVID-19) in Portugal keeps rising, the risk of complications, although rare, keeps rising too. We report a case of vaccine-induced thrombotic thrombocytopenia (VITT) in a 30-year-old previously healthy male after vaccination with Ad26.COV2.S. The patient presented to the emergency department (ED) with abdominal pain and headache. Laboratory tests revealed thrombocytopenia, high D-dimer levels, and fibrinogen consumption. Thoracoabdominal CT scan showed a thrombus in the portal mesenteric venous axis. A positive PF4 heparin enzyme-linked immunosorbent assay confirmed the VITT diagnosis, and the patient was started on intravenous immunoglobulin. Both clinical complaints and laboratory findings resolved within six days, and he was discharged to follow-up. This case shows that general symptoms after vaccination should not be depreciated, highlights the importance of early diagnosis and treatment, and raises new questions about the follow-up and further study of these patients.