Hereditary Motor and Sensory Neuropathy with Cataract - HYCCIN

Klinische Symptomatik

Patients with hypomyelinating leucodystrophy with congenital cataract (HCC) reveal congenital cataract, progredient neurological impairment as wellas a diffuse lack of myelin (visible in MRT). A psychomotoric retardation begins at the end of the first year of life. Walking is only possible with support. Pyramidal and cerebellar dysfunction increases, sometimes with dysarthry and intention tremor. Muscle weakness and atrophy frequently occur in the lower extremities. Mental retardation is mildly to medium. Cortex and grey matter remain unaffected, but a diffuse cerebral hypomyelinisation occurs. Neurophysiologically, a peripheral neuropathy is observed in almost all cases. Sural nerve biopsy also reveals signs of a hypomyelination and a mild axonal loss (depending on the stage of development).

Genetik

HCC is an autosomal recessive inheritance. The HYCCIN gene is located on chromosome 7p15.3. Other names for this gene are Downregulated by CTNNB1, protein A (DRCTNNB1A) and Family with sequence similarity 126, member A (FAM126A).

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Diagnostik