A recognizable type of syndromic short stature with arthrogryposis caused by bi-allelic SEMA3A loss-of-function variants.

The semaphorins constitute a large family of secreted and membrane-associated proteins that regulate many developmental processes, including neural circuit assembly, bone formation and angiogenesis. Recently, bi-allelic loss-of-function variants in SEMA3A (semaphorin 3A) were identified in a single patient with a particular pattern of multiple congenital anomalies (MCA). Using homozygosity mapping combined with exome sequencing, we identified a homozygous SEMA3A variant causing a premature stop codon in an 8 year old boy with the same pattern of MCA. The phenotype of these patients is characterized by postnatal short stature, skeletal anomalies of the thorax, a minor congenital heart or vascular defect, camptodactyly, micropenis, and variable additional anomalies. Motor development is delayed in both patients, and intellectual development is delayed in one patient. Our observation of a second case supports the notion that bi-allelic mutations in SEMA3A cause an autosomal recessive type of syndromic short stature.

Modification of risk for cancer as a coincidental finding in DNA array investigation.

The high resolution of modern DNA arrays has the implification of unintended coincidental detection of gene deletions predisposing to late-onset neurological and oncological disorders. Here, we report the case of an 18-year-old girl with mild intellectual disability, facial dysmorphisms, and a microdeletion of approximately 6.3 Mb on 22q12.1q12.3 including NF2, the gene for neurofibromatosis type 2, and CHEK2, a modifier gene for breast cancer. Subsequent magnetic resonance imaging of the brain showed she had already developed bilateral vestibular schwannomas. The challenge of DNA arrays and the consequences for genetic counselling and informed consent will be discussed in the light of this unique case with a microdeletion including both a high risk and a moderate risk cancer predisposition gene.