Sinus pauses and high-grade atrioventricular block in Albright's hereditary osteodystrophy with pseudopseudohypoparathyroidism.

Albright's hereditary osteodystrophy (AHO) is a rare inherited syndrome involving the molecular defects in the gene encoding the α subunit of the stimulatory G protein (Gsα). AHO has several variants, mainly pseudohypoparathyroidism (PHP) and pseudopseudohypoparathyroidism (PPHP). We present a family that share the same inactivating GNAS1 mutation, the daughter being affected by PPHP and her late father with PHP. The daughter, in her late teens, presented with a long history of presyncopal and syncopal attacks. Her father died suddenly in his mid-40 s. As expected, her laboratory tests to date have shown normal biochemistry and hormonal levels. Subsequently, an implantable loop recorder was inserted. This demonstrated extreme sinus pauses of >11 s and also high-grade atrioventricular block. A dual-chamber pacemaker was therefore inserted.