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Savant characteristics in a child with developmental delay and deletion in the short arm of chromosome 20
J Rovet1, K Krekewich, K Perlman
1Department of Psychology, Hospital for Sick Children, Toronto, Ontario, Canada.
Insights
A four-year-old boy with chromosome 20 deletion showed advanced reading skills despite developmental delays. His profile highlights exceptional memory and fantasy, contrasting with motor and math challenges.
Area of Science:
- Genetics
- Neurodevelopmental disorders
- Child psychology
Background:
- A case study of a four-year-old boy with a deletion on the short arm of chromosome 20.
- The child experienced early medical issues, including infantile hypoglycemic convulsions due to growth hormone deficiency.
- Initial delays were noted in motor and language development.
Observation:
- The child demonstrated self-taught reading skills from 2.5 years old.
- He exhibited computer proficiency, an exceptional memory for spatial information (maps, locations), and a rich fantasy life.
- Good diction and an extensive vocabulary were also observed.
Findings:
- Neuropsychological evaluation indicated low-average overall intelligence.
- Language, memory, and attention functions were within normal limits.
- Significant impairments were found in visuomotor, graphomotor abilities, and general motor skills.
- Advanced decoding and reading comprehension contrasted with average abilities in mathematics, spelling, and general knowledge.
Implications:
- This case highlights the complex and heterogeneous neurodevelopmental outcomes associated with chromosome 20 deletions.
- It underscores the potential for specific cognitive strengths, such as early literacy and spatial memory, to emerge despite global developmental challenges.
- Further research into genotype-phenotype correlations in chromosome 20 abnormalities is warranted to understand such unique developmental trajectories.
Abstract:
The development outcome of a four-year-old boy with a deletion of the short arm of chromosome 20 is described. Despite a number of early medical problems, including infantile hypoglycemic convulsions secondary to growth hormone deficiency and delayed motor and language development, he has been reading (self-taught) since 2.5 years and currently has computer proficiency, and exceptional memory for maps and spatial locations, an extremely rich and active fantasy life, good diction, and an extensive spoken vocabulary. Neuropsychological evaluation revealed low-average intelligence with normal language, memory and attention functions, and impaired visuomotor and graphomotor ability and motor skills. He showed extremely advanced decoding and reading comprehension skills while mathematics, spelling and general knowledge abilities were average.