Identification of Pathogenic Variants Causes Microcephaly In Sindh Families


  • Zaib-Un-Nisa Mughal Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
  • Jawaid Ahmed Zai Department of Physiology, University of Sindh, Jamshoro
  • Muhammad Ansar Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
  • Ali Muhammad Memon Department of Physiology, University of Sindh, Jamshoro, Pakistan



MCPH, ASPM, DNA isolation, Mutation, Sanger Sequencing


 Introduction: The study was designed to identify the genetic mutation in families with autosomal recessive primary microcephaly (MCPH). Methodology: The present study was cross-sectional and conducted at the Department of Biochemistry, Quaid-e-Azam University, Islamabad in 2017. The two families (A and B) with MCPH phenotype randomly selected from Hyderabad and Tando Adam districts respectively. Informed written consent was taken, physical parameters were measured and blood samples were collected from both families. DNA was extracted from whole blood and PCR was performed. The ASPM gene located on chromosome 1 is known to play a vital role in mitotic spindle fiber regulation during neurogenesis, and also is the most probable causative agent of microcephaly. Therefore targeted Sanger sequencing method for the ASPM gene was selected for variant identification in both families. Results: The Sanger sequencing result showed the novel missense variant (c.5841T/C; p. K1862E) in 18 exon of ASPM gene in Family A  and this variant predicted as damaging in mutation tester, and provean and also exhibited deleterious in Polyphen 2 and SIFT public database. Similarly in family B we found a previously reported protein pre termination variant (c.3978G/A; p.Trp1326*) (rs137852995) in exon 17 of ASPM gene. The later mutation was most predominant cause of microcephaly in KPK families. Conclusion: Therefore it is concluded that mutation in the ASPM gene is the most prominent genetic player of Microcephaly in Pakistani families. The current study aids in the genetic analysis of MCPH phenotype families in Pakistan alongwith the counseling of MCPH families.


Ponting C, Jackson AP. Evolution of primary microcephaly genes and the enlargement of primate brains. Curr Opin Genet Develop 2005; 15(3): 241-8.

Mughal Zu, Zai JA, Ansar M. A Missense variant in LAMA3 gene causes microcephaly and epidermolysis bullosa in a Pakistani family. J Liaquat Univ Med Health Sci 2021; 20(3): 198-203.

Woods CG. Human microcephaly. Curr Opin Neurobiol 2004; 14(1): 112-7.

Zaqout S, Morris-Rosendahl D, Kaindl AM. Autosomal recessive primary microcephaly (MCPH): an update. Neuropediatrics 2017; 48(03): 135-42.

Hussain S, Nawaz A, Hamid M, Ullah W, Khan IN, Afshan M, et al. Mutation screening of multiple Pakistani MCPH families revealed novel and recurrent protein‐truncating mutations of ASPM. Biotechnol Appl Biochem 2021 Nov 26.

Nicholas AK, Khurshid M, Désir J, Carvalho OP, Cox JJ, Thornton G, et al. WDR62 is associated with the spindle pole and is mutated in human microcephaly. Nature Genetics 2010; 42(11): 1010-4.

Bond J, Roberts E, Springell K, Lizarraga S, Scott S, Higgins J, et al. A centrosomal mechanism involving CDK5RAP2 and CENPJ controls brain size. Nature Genetics 2005; 37(4): 353-5.

Bond J, Roberts E, Mochida GH, Hampshire DJ, Scott S, Askham JM, et al. ASPM is a major determinant of cerebral cortical size. Nature Genetics 2002; 32(2): 316-20.

Hussain MS, Baig SM, Neumann S, Nürnberg G, Farooq M, Ahmad I, et al. A truncating mutation of CEP135 causes primary microcephaly and disturbed centrosomal function. Am J Human Genetics 2012; 90(5): 871-8.

Guernsey DL, Jiang H, Hussin J, Arnold M, Bouyakdan K, Perry S, et al. Mutations in centrosomal protein CEP152 in primary microcephaly families linked to MCPH4. Am J Human Genetics 2010; 87(1): 40-51.

Khan MA, Rupp VM, Orpinell M, Hussain MS, Altmüller J, Steinmetz MO, et al. A missense mutation in the PISA domain of HsSAS-6 causes autosomal recessive primary microcephaly in a large consanguineous Pakistani family. Human Mol Genet 2014; 23(22): 5940-9.

Hussain MS, Baig SM, Neumann S, Peche VS, Szczepanski S, Nürnberg G, et al. CDK6 associates with the centrosome during mitosis and is mutated in a large Pakistani family with primary microcephaly. Human Mol Genet 2013; 22(25): 5199-214.

Moawia A, Shaheen R, Rasool S, Waseem SS, Ewida N, Budde B, et al. Mutations of KIF14 cause primary microcephaly by impairing cytokinesis. Annals Neurol 2017; 82(4): 562-77.

Alakbarzade V, Hameed A, Quek DQ, Chioza BA, Baple EL, Cazenave-Gassiot A, et al. A partially inactivating mutation in the sodium-dependent lysophosphatidylcholine transporter MFSD2A causes a non-lethal microcephaly syndrome. Nature Genet 2015; 47(7): 814-7.

Braun DA, Lovric S, Schapiro D, Schneider R, Marquez J, Asif M, et al. Mutations in multiple components of the nuclear pore complex cause nephrotic syndrome. J Clin Invest 2018; 128(10): 4313-28.

Khan MA, Windpassinger C, Ali MZ, Zubair M, Gul H, Abbas S, et al. Molecular genetic analysis of consanguineous families with primary microcephaly identified pathogenic variants in the ASPM gene. J Genet 2017; 96(2): 383-7.

Abuelo D. Microcephaly syndromes. In Seminars in pediatric neurology 2007; 14(3): 118-27.

Do Carmo Avides M, Glover DM. Abnormal spindle protein, Asp, and the integrity of mitotic centrosomal microtubule organizing centers. Science 1999; 283(5408): 1733-5.

Kouprina N, Pavlicek A, Collins NK, Nakano M, Noskov VN, Ohzeki JI, et al. The microcephaly ASPM gene is expressed in proliferating tissues and encodes for a mitotic spindle protein. Human Mol Genet 2005; 14(15): 2155-65.

Saunders RD, Avides MD, Howard T, Gonzalez C, Glover DM. The Drosophila gene abnormal spindle encodes a novel microtubule-associated protein that associates with the polar regions of the mitotic spindle. The Journal of cell biology. 1997 May 19; 137(4): 881-90.

Tsang WY, Spektor A, Luciano DJ, Indjeian VB, Chen Z, Salisbury JL, et al. CP110 cooperates with two calcium-binding proteins to regulate cytokinesis and genome stability. Mol Biol Cell 2006; 17(8): 3423-34.

Kousar R, Nawaz H, Khurshid M, Ali G, Khan SU, Mir H, et al. Mutation analysis of the ASPM gene in 18 Pakistani families with autosomal recessive primary microcephaly. J Child Neurol 2010; 25(6): 715-20.

Ahmad I, Baig SM, Abdulkareem AR, Hussain MS, Sur I, Toliat MR, et al. Genetic heterogeneity in Pakistani microcephaly families revisited. Clin Genet 2017; 92(1): 62-8.

Wang R, Khan A, Han S, Zhang X. Molecular analysis of 23 Pakistani families with autosomal recessive primary microcephaly using targeted next-generation sequencing. J Human Genet 2017; 62(2): 299-304.




How to Cite

Mughal, Z.-U.-N., Zai, J. A., Muhammad Ansar, & Memon, A. M. (2023). Identification of Pathogenic Variants Causes Microcephaly In Sindh Families. BioSight, 4(1), 11–16.



Original Article