CD55-deficiency in Jews of Bukharan descent is caused by the Cromer blood type Dr(a-) variant.
Hum Genet
; 142(5): 683-690, 2023 May.
Article
em En
| MEDLINE
| ID: mdl-35314883
ABSTRACT
The complement system regulator CD55 was initially found to carry the Cromer blood group system antigens, and its complete loss of function was subsequently revealed to cause a severe monogenic gastrointestinal syndrome characterized by protein-losing enteropathy and susceptibility to venous thrombosis. Here we present homozygosity to the CD55 c.596C>T; p.Ser199Leu variant, which was previously described as the Cromer Dr(a-) genotype, in two Bukharan Jewish CD55-deficiency patients with variable disease severity. We confirm that this missense variant causes aberrant splicing and deletion of 44 bp in exon 5, leading to premature termination and low expression of the CD55 protein. Furthermore, Patient 1 exhibited a mildly abnormal B cell immunophenotyping profile. By population screening we established that this variant is highly prevalent in the Bukharan Jewish population, with a carrier frequency of 117, suggesting that many similar patients are un- or mis-diagnosed. The phenotypic variability, ranging from abdominal pain when eating a high-fat diet to the full CD55-deficiency phenotype, is likely related to modifiers affecting the proportion of the variant that is able to escape aberrant splicing. Establishing the diagnosis of CD55-deficiency in a timely manner, even in patients with milder symptoms, may have a critical effect on their management and quality-of-life since treatment with the complement inhibitor eculizumab is highly effective in ameliorating disease manifestations. Awareness of founder mutations within certain populations can further guide genetic testing and prevent a diagnostic odyssey, by placing this CD55 variant high on the differential diagnosis.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Antígenos de Grupos Sanguíneos
/
Judeus
Limite:
Humans
Idioma:
En
Revista:
Hum Genet
Ano de publicação:
2023
Tipo de documento:
Article
País de afiliação:
Israel