Identification of Chromosome Abnormalities in Subtelomeric Regions Using Multiplex Ligation Dependent Probe Amplification (MLPA) Technique in 100 Iranian Patients With Idiopathic Mental Retardation

Farkhondeh Behjati; Saghar Ghasemi Firouzabadi; Firoozeh Sajedi; Kimia Kahrizi; Mostafa Najafi; Behruz Ebrahimizade Ghasemlou; Yousef Shafeghati; Fatemeh Behnia; Ali Reza Mohammadi Arya; Hossein Karimi; Fatemeh Hadipour; Zahra Hadipour; Peyman Jamali; Roxana Kariminejad; Hossein Darvish; Ideh Bahman; Eiman Bagherizadeh; Hossein Najmabadi; Roshanak Vameghi

doi:10.5812/ircmj.8221

Identification of Chromosome Abnormalities in Subtelomeric Regions Using Multiplex Ligation Dependent Probe Amplification (MLPA) Technique in 100 Iranian Patients With Idiopathic Mental Retardation

Iran Red Crescent Med J. 2013 Oct;15(10):e8221. doi: 10.5812/ircmj.8221. Epub 2013 Oct 5.

Authors

Farkhondeh Behjati¹, Saghar Ghasemi Firouzabadi¹, Firoozeh Sajedi², Kimia Kahrizi¹, Mostafa Najafi¹, Behruz Ebrahimizade Ghasemlou¹, Yousef Shafeghati³, Fatemeh Behnia⁴, Ali Reza Mohammadi Arya⁵, Hossein Karimi⁶, Fatemeh Hadipour⁷, Zahra Hadipour⁷, Peyman Jamali⁸, Roxana Kariminejad⁹, Hossein Darvish¹⁰, Ideh Bahman¹, Eiman Bagherizadeh⁷, Hossein Najmabadi¹, Roshanak Vameghi²

Affiliations

¹ Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, IR Iran.
² Pediatric Neurorehabilitation Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, IR Iran.
³ Sarem Cell Research Center, Sarem Hospital, Tehran, IR Iran ; Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, IR Iran.
⁴ Department of Occupational Therapy, University of Social Welfare and Rehabilitation Sciences, Tehran, IR Iran.
⁵ University of Social Welfare and Rehabilitation Sciences, Tehran, IR Iran.
⁶ Zafar Rehabilitation Clinic, Tehran, IR Iran.
⁷ Sarem Cell Research Center, Sarem Hospital, Tehran, IR Iran.
⁸ Shahroud Welfare Organization, Shahroud, IR Iran.
⁹ Pathology and Genetics Center, Tehran, IR Iran.
¹⁰ Department of Medical Genetics, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.

Abstract

Background: Mental retardation/Developmental delay (MR/DD) is present in 1 - 3% of the general population (1, 2). MR is defined as a significant impairment of both cognitive (IQ < 70) and social adaptive functions, with onset before 18 years of age.

Objectives: The purpose was to determine the results of subtelomeric screening by the Multiplex Ligation Dependent Probe Amplification (MLPA) Technique in 100 selected patients with idiopathic mental retardation (IMR) in Iran.

Materials and methods: A number of 100 patients with IMR, normal karyotypes and negative fragile-X and metabolic tests were screened for subtelomeric abnormalities using MLPA technique.

Results: Nine of 100 patients showed subtelomeric abnormalities with at least one of the two MLPA kits. Deletion in a single region was found in 3 patients, and in two different subtelomeric regions in 1 patient. Duplication was only single and was present in 2 patients. Three patients were found to have both a deletion and duplication.MLPA testing in the parental samples of 7 patients which was accessible showed that 4 patients were de novo, 2 patients had inherited from a clinically normal mother, and one had inherited from a clinically normal father. Screening with the two MLPA kits (SALSA P036 and SALSA P070) proved abnormality in only five of the 9 patients.

Conclusions: So, the prevalence rate of abnormal subtelomeres using MLPA technique in patients with idiopathic MR in our study was 5 - 9%, the higher limit referring to the positive results of one of the two MLPA kits, and the lower limit representing the results of positive double-checking with the two MLPA kits.

Keywords: Hypersomnolence Idiopathic; Ligation; Mental Retardation.