A Boy with an LCR3/4-Flanked 10q22.3q23.2 Microdeletion and Uncommon Phenotypic Features

Patients with 10q22.3q23.1 recurrent deletion syndrome are at risk for juvenile polyposis

Juvenile polyposis syndrome (JPS) is a rare autosomal dominant predisposition to hamartomatous polyps within the gastrointestinal tract, at high risk for malignant transformation. BMPR1A and SMAD4 loss-of-function variants account for 50% of the cases. More specifically, point mutations and structural abnormalities in BMPR1A lead to a highly penetrant yet variable phenotype of JPS. Intriguingly, in the developmental disorder caused by a recurrent 10q22.3q23.1 7 Mb deletion which includes BMPR1A, juvenile polyps have never been reported. We present the case of a young adult harboring this recurrent deletion, in a context of intellectual disability, ventricular septal defect and severe juvenile polyposis syndrome diagnosed at the age of 25 years, requiring a surgical preventive colectomy. She developed a gastric adenocarcinoma from which she died at the age of 32. We hypothesize that with the current available pangenomic CNV arrays, the diagnosis of 10q22.3q23.1 deletion is often made several years before the onset of the digestive phenotype, which could explain the absence of reports for juvenile polyps. This observation highlights the importance of an active digestive surveillance of patients with 10q22.3q23.1 deletion.

On the significance of craniosynostosis in a case of Kabuki syndrome with a concomitant KMT2D mutation and 3.2 Mbp de novo 10q22.3q23.1 deletion

Craniosynostosis has rarely been described in patients with Kabuki syndrome. We report here a boy with facial asymmetry due to combined premature synostosis of the right coronal and sagittal sutures as well as several symptoms reminiscent of Kabuki syndrome (KS). Our case supports previous observations and suggests that craniosynostosis is a part of the KS phenotype. The uniqueness of our case is the sporadic co-occurrence of two genetic disorders, that is, a de novo frameshift variant in the KMT2D gene and a de novo 3.2 Mbp 10q22.3q23.1 deletion. Our findings emphasize the importance of the initial clinical assessment of children with craniosynostosis and that genomic and monogenic disorders, such as Kabuki syndrome, should be considered among the differential diagnoses of syndromic forms of craniosynostosis.

A New Case of the Rare 10q22.3q23.2 Microdeletion Flanked by Low-Copy Repeats 3/4

Deletions in the 10q22.3q23.2 region are rare and mediated by 2 low-copy repeats (LCRs 3 and 4). These deletions have already been recognized as the 10q22q23 deletion syndrome. The phenotype associated with this condition is rather uncharacteristic, and most common features are craniofacial dysmorphisms and developmental delay. We describe a boy with craniofacial dysmorphic features, developmental delay, tetralogy of Fallot, hand/foot abnormalities, and recurrent respiratory tract infections. Chromosomal microarray analysis disclosed a 7.8-Mb microdeletion at 10q22.3q23.2, flanked by LCRs 3/4, and an additional 16q12.1 microdeletion of 189 kb. This article reviews the clinical signs of reported cases with similar deletions and compares them with our patient, contributing to a better understanding of genotype-phenotype correlation.