[Clinical characteristics of early juvenile GM2 gangliosidosis: a case report]

Area of Science:

• Neuroscience
• Genetics
• Pediatric Neurology

Background:

• GM2 gangliosidosis is a rare lysosomal storage disorder.
• Juvenile forms typically present with specific neurological and developmental patterns.

Observation:

• A 15-year-old male presented with early juvenile GM2 gangliosidosis, manifesting as progressive clumsiness and motor regression from 1.5 years.
• Intellectual disability appeared later, at age 6, with rapid motor deterioration post-varicella infection.
• Unusual features included lack of startle response, no macrocephaly, minimal myoclonus, autistic behaviors (phonophobia), and initial cerebral atrophy preceding cerebellar atrophy.

Findings:

• The patient's presentation deviated from typical juvenile GM2 gangliosidosis, particularly the pattern of brain atrophy (cerebral then cerebellar) and the late onset of intellectual disability.
• The occurrence of autistic behavioral problems was also noted as an unusual characteristic.

Implications:

• Recognizing these atypical features is vital for accurate diagnosis of GM2 gangliosidosis.
• This case provides insights into the varied pathomechanisms of GM2 gangliosidosis.
• Understanding these variations can guide future research and clinical management.