Clinical and molecular characterization of an extended family with Fabry disease

To characterize clinical manifestations, biochemical changes, mutation of alpha-Galactosidase (alpha-Gal A) gene A (GLA), and functional capability of mutant protein.

Seventeen subjects from a family with a newly diagnosed patient with Fabry disease were enrolled in the present study. In each individual, clinical history, physical examination, leukocyte enzyme activity of alpha-Gal A, and mutation analysis were performed. Those with a mutation were further investigated by ophthalmological and audiological evaluations, electrocardiography, echocardiogram, urinalysis, and blood tests to determine renal insufficiency. Expression study of the mutant protein was performed using a Pichia pastoris expression system.

Four affected males and five symptomatic female carriers were identified. Clinical manifestations included severe neuropathic pain, acroparesthesia, hypo-/hyper-hidrosis, frequent syncope, ischemic stroke, cardiac hypertrophy, corneal dystrophy and cart-wheel cataract, high frequency sensorineural hearing loss, periorbital edema and subcutaneous edema over hands and interphalangeal joints. None had angiokeratoma or renal symptoms. The authors identified a novel mutation, p.L106R, in the GLA gene. Recombinant expression of the mutant protein gave little or no enzyme activity compared to the normal protein.

There were intrafamilial clinical variabilities, but consistent findings of the absence of angiokeratoma and renal symptoms, which could represent a unique feature of this particular mutation.