Autosomal dominant cone dystrophy-cerebellar atrophy (ADCoCA) (modified ADCA Harding II)

Abstract

An autosomal dominant cone dystrophy-cerebellar atrophy (ADCoCA) pedigree (with symptoms of variable penetration) over five generations is described. Visual deterioration may start in early childhood and precede the cerebellar ataxia by many years, while the ophthalmo-logical as well as the neurological signs and symptoms may practically remain silent throughout life. Next to those carriers, fully unaffected members may transmit the disease. This ADCoCA is characterized initially by a tritan-colour defect and bull's eye macula, characteristic for cone dystrophy, progressing to photoreceptor dystrophy over the entire retina, with progressive extinction of the photopic and scotopic ERG (cone-rod dystrophy).

Histopathology shows progressive loss of photoreceptors, degeneration of afferent and efferent cerebellar pathways, hemispheric cerebellar cortical atrophy, loss of retinal ganglion cells, trans-geniculate atrophy of the optic pathway, typical involvement and atrophy of the corpus subthalami-cum and pallidum, progressive involvement of lower motor nuclei of the brainstem, loss of neurons in the anterior horn of the spinal cord and slight atrophy of the pyramidal pathways. This is one of the rare families where a dominant cone dystrophy combined with ataxia, has been documented throughout an entire family, as many cases are observed later in life and described as tapetoretinal degeneration and (or) optic atrophy, whereas both latter are only secondary, but may appear primary, as the natural course of the disease is lacking.

Key Words:

• cone dystrophy
• cerebellar atrophy
• ataxia (heredity)
• autosomal dominant