Familial cryptic translocation between chromosomes 2qter and 8qter: further delineation of the Albright hereditary osteodystrophy-like phenotype

Recently five patients with an Albright hereditary osteodystrophy (AHO)-lik e phenotype were reported to have a subtelomeric deletion of the long arm o f chromosome 2. These patients showed a striking resemblance to a number of patients from a large pedigree known to us for a long time. After molecula r confirmation of a subtelomeric deletion in one patient, FISH analysis was used and a cryptic translocation between the long arms of chromosomes 2 an d 8, t(2;8)(q37.3;q24.3), was detected. Remarkably, five proven and 10 prob able cases with a 2qter deletion were found in the family, but none with an 8qter deletion. This was not explained by increased fetal loss. The major clinical characteristics of terminal 2q deletion are a short, sto cky build, round face, sparse hair, deeply set eyes, bulbous nose, thin ver milion border, brachymetaphalangism, seizures, and developmental delay. A s pecific behavioural phenotype consisting of periods of hyperkinesia and agg ression can develop with age. The overall phenotype is sufficiently charact eristic to allow clinical recognition. The cytogenetic and molecular studies did not narrow down the common delete d region. Both testing of additional 2q markers and characterisation of oth er AHO-like patients with 2q37 microdeletions may help to define the candid ate gene region.