Patients with Chromosome 11q Deletions Are Characterized by Inborn Errors of Immunity Involving both B and T Lymphocytes

Prenatal diagnosis of Jacobsen syndrome associated with a distal 11q deletion and a distal 8q duplication by chromosome microarray analysis in a fetus with a de novo unbalanced translocation of 46,XX,der(11)t(8;11)(q24.13;q23.3) and multiple congenital anomalies on fetal ultrasound

OBJECTIVE

We present prenatal diagnosis of Jacobsen syndrome associated with a distal 11q deletion and a distal 8q duplication by chromosome microarray analysis (CMA) in a fetus with multiple congenital anomalies on fetal ultrasound.

CASE REPORT

A 41-year-old, gravida 2, para 1, woman underwent amniocentesis at 25 weeks of gestation because of intrauterine growth restriction, endocardial cushion defect, clenched hands, arthrogryposis, rocker bottom feet and craniosynostosis on fetal ultrasound. Amniocentesis revealed a karyotype of 46,XX,add(11)(q23.3). Array comparative genomic hybridization (aCGH) analysis of the DNA extracted from the uncultured amniocytes revealed the result of arr 8q24.13q24.3 × 3, 11q23.3q25 × 1. Analysis of FGFR2 revealed no mutation. The karyotype was 46,XX,der(11)t(8;11)(q24.13;q23.3). The parental karyotypes were normal. The pregnancy was subsequently terminated, and a dead malformed fetus was delivered with craniofacial dysmorphism of low-set malformed ears, depressed nasal bridge, hypertelorism, small mouth, clenched hands and rocker bottom feet. Cytogenetic analysis of the placenta revealed a karyotype of 46,XX,der(11)t(8;11)(q24.13;q23.3). aCGH analysis of the DNA extracted from the umbilical cord showed the result of arr 8q24.13q24.3 (126,302,369-146,280,020) × 3.0, arr 11q23.3q25 (120,469,928-134,868,407) × 1.0 [GRCh37] with a 19.978-Mb duplication of 8q24.13-q24.3 and a 14.398-Mb deletion of 11q23.3-q25 encompassing the genes of BSX, ETS1, FLI1 and ARHGAP32.

CONCLUSION

CMA is useful for detection of de novo chromosomal rearrangement in the fetus with multiple congenital anomalies on fetal ultrasound.

Case report: ETS1 gene deletion associated with a low number of recent thymic emigrants in three patients with Jacobsen syndrome

Jacobsen syndrome is a rare genetic disorder associated with a terminal deletion in chromosome 11. The clinical presentation is variable. Although immunodeficiency has been described in patients with Jacobsen syndrome, a clear genotype-phenotype correlation has not yet been established. Here, we report on the immunologic phenotypes of four patients with Jacobsen syndrome. All four patients showed one or more atypical immunologic features. One patient suffered from recurrent viral infections, two patients had experienced a severe bacterial infection and one had received antibiotic prophylaxis since early childhood. One patient had experienced severe, transient immune dysregulation. Hypogammaglobulinemia and low B cell counts were found in two patients, while the number of recent thymic emigrants (CD31+CD45RA+ CD4 cells) was abnormally low in three. When considering the six immune-related genes located within the affected part of chromosome 11 (ETS1, TIRAP, FLI1, NFRKB, THYN1, and SNX19), only the ETS1 gene was found be deleted in the three patients with low numbers of recent thymic emigrants and non-switched memory B cells. Our findings support the hypothesis whereby Jacobsen syndrome is associated with a combined immunodeficiency with variable presentation. Further investigations of potential genotype-phenotype correlations are warranted and might help to personalize patient management in individuals lacking immune-related genes. In addition, we recommend immunologic follow-up for all patients with Jacobsen syndrome, as immune abnormalities may develop over time.