Think about it: FMR1 gene mosaicism.
Francesca Andrea Bonarrigo1, Silvia Russo2, Paola Vizziello3
1Pediatric Clinic 1, Department of Pathophysiology and Transplantation, University of Milan Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
Journal of Child Neurology
|September 26, 2013
Summary
Fragile X syndrome (FXS), a common cause of intellectual disability, can present with mild symptoms. This case highlights rare FMR1 gene mosaicism, emphasizing the need for early diagnosis in subtle cases.
Area of Science:
- Genetics
- Neurodevelopmental Disorders
- Molecular Biology
Background:
- Fragile X syndrome (FXS) is a leading genetic cause of intellectual disability and autism.
- It typically results from CGG trinucleotide repeat expansion in the FMR1 gene, leading to protein dysfunction.
Observation:
- A 4-year-old boy presented with mild psychomotor delay and no significant dysmorphic features.
- Molecular analysis revealed a rare mosaic pattern in the FMR1 gene, with one normal and one fully mutated allele.
Findings:
- The patient's FMR1 gene analysis demonstrated mosaicism for repeat size and methylation.
- This rare genetic finding in FXS underscores the variability of clinical presentation.
Implications:
- Physicians should consider FXS in patients with even mild developmental delays.
- Early diagnosis is crucial for effective patient rehabilitation and informed family planning.
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