7 Mb de novo deletion within 8q21 in a patient with distal arthrogryposis type 2B (DA2B)

We report on a 7 11/12 years old male patient with normal mental development, club feet, ulnar deviation and mild camptodactyly as well as facial dysmorphism including high forehead, small mouth, broad nasal bridge, epicanthus, high palate, brachycephalus, short neck, and dysplastic ears consistent with distal arthrogryposis type 2B (DA2B). Mutational analysis of the genes MYH3, TNNI2, TNNT3 and TPM2, known to cause DA2B revealed no apparent disease causing mutation. Molecular karyotyping using a 250 K SNP array revealed a heterozygous de novo 7 Mb deletion of 8q21.11–8q21.13 containing 23 genes. Prioritisation of possible candidate genes using the bioinformatics tool ENDEAVOUR revealed three favoured genes, HEY1, FABP5 and FABP4 as potential causes of the phenotype. We propose that the 8q21 region contains a further locus which contributes to the genetically heterogeneous DA2B.

► We describe a patient with distal arthrogryposis type 2B (DA2B).
► The patient has a de novo 7 Mb deletion in 8q21.
► We propose that the 8q21 region contains a further locus for DA2B.
► Of note, the patient shows normal mental development.