Fragile X syndrome clinical and associated comorbidities | ||
| Middle East Journal of Medical Genetics | ||
| Volume 10, Issue 1, October 2021 PDF (1.01 M) | ||
| DOI: 10.4103/MXE.MXE_11_20 | ||
| Authors | ||
| Hisham Megahed; Ola Shaheen; Hala Hamza; Miral M. Refeat | ||
| Abstract | ||
| Background Fragile X syndrome (FXS) is the most common inherited cause of intellectual developmental delay, affecting 1 in 4000 males and 1 in 8000 females. It is caused by expansion of CGG trinucleotide repeats in the 5' untranslated region of the fragile X mental retardation 1 () gene that leads to hypermethylation. Fragile X represents with certain physical manifestations; however, a spectrum of subtle medical problems may occasionally be associated with these children. Aim The aim of this study is to highlight the prevalence of fragile X-associated subtle medical problems confirmed by bisulfate treatment and methylation-specific (MS)-PCR assay as a sensitive, accurate, and rapid technique. Patients and methods The current study included 32 Egyptian male children clinically diagnosed with fragile X symptoms. Their ages ranged from 4.2 to 11.9 years, with an average age of 7.5 years. All cases were subjected to thorough physical, clinical, and neurological examinations and confirmed by molecular analysis using conventional PCR, followed by bisulfite treatment and MS-PCR. Results Recurrent seizures were the main presenting complaint in 14 (43.75%) patients, autism spectrum disorder in seven (21.8%) patients, attention-deficit hyperactivity disorder in six (18.7%) patients, and delayed language development in four (12.5%) patients. Cardiac anomalies were found in five (15.6%) cases, four (12.5%) patients had strabismus, two (6.25%) patients had otitis media, and another two (6.25%) patients had gastrointestinal problems. Some patients exhibited more than one clinical presentation. MS-PCR of gene revealed full mutations with CGG repeats of more than 200 in 24 (75%) patients, and premutation alleles with CGG repeats ranged from 55 to 200 in eight (25%) cases. Conclusion Children with FXS should be subjected to specific and accurate checklist of physical, neurological, cardiac, ophthalmic, and ENT examinations. MS-PCR assay is a useful technique for rapid and accurate molecular diagnosis of FXS. This may allow early detection, diagnosis, and management of these subtle medical problems. | ||
| Keywords | ||
| attention-deficit hyperactivity disorder; Autism Spectrum Disorder; Epilepsy; Fragile X syndrome; full mutation; Intellectual Disability; methylation-specific PCR | ||
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