Targeted Gene Sanger Sequencing Should Remain the First-Tier Genetic Test for Children Suspected to Have the Five Common X-Linked Inborn Errors of Immunity
Authors: Chan Koon-Wing , Wong Chung-Yin , Leung Daniel , Yang Xingtian , Fok Susanna F. S. , Mak Priscilla H. S. , Yao Lei , Ma Wen , Mao Huawei , Zhao Xiaodong , Liang Weiling , Singh Surjit , Barbouche Mohamed-Ridha , He Jian-Xin , Jiang Li-Ping , Liew Woei-Kang , Le Minh Huong Thi , Muktiarti Dina , Santos-Ocampo Fatima Johanna , Djidjik Reda , Belaid Brahim , Ismail Intan Hakimah , Abdul Latiff Amir Hamzah , Lee Way Seah , Chen Tong-Xin , Liu Jinrong , Jin Runming , Wang Xiaochuan , Chien Yin Hsiu , Yu Hsin-Hui , Raj Dinesh , Raj Revathi , Vaughan Jenifer , Urban Michael , Berg Sylvia van den , Eley Brian , Lee Anselm Chi-Wai , Isa Mas Suhaila , Ang Elizabeth Y. , Lee Bee Wah , Yeoh Allen Eng Juh , Shek Lynette P. , Quynh Le Nguyen Ngoc , Nguyen Van Anh Thi , Phan Nguyen Lien Anh , Capulong Regina D. , Mallillin Joanne Michelle , Villanueva Jose Carlo Miguel M. , Camonayan Karol Anne B. , Vera Michelle De , Casis-Hao Roxanne J. , Lobo Rommel Crisenio M. , Foronda Ruby , Binas Vicky Wee Eng , Boushaki Soraya , Kechout Nadia , Phongsamart Gun , Wongwaree Siriporn , Jiratchaya Chamnanrua , Lao-Araya Mongkol , Trakultivakorn Muthita , Suratannon Narissara , Jirapongsananuruk Orathai , Chantveerawong Teerapol , Kamchaisatian Wasu , Chan Lee Lee , Koh Mia Tuang , Wong Ke Juin , Fong Siew Moy , Thong Meow-Keong , Latiff Zarina Abdul , Noh Lokman Mohd , Silva Rajiva de , Jouhadi Zineb , Al-Saad Khulood , Vignesh Pandiarajan , Jindal Ankur Kumar , Rawat Amit , Gupta Anju , Suri Deepti , Yang Jing , Au Elaine Yuen-Ling , Kwok Janette Siu-Yin , Chan Siu-Yuen , Hui Wayland Yuk-Fun , Chua Gilbert T. , Duque Jaime Rosa , Cheong Kai-Ning , Chong Patrick Chun Yin , Ho Marco Hok Kung , Lee Tsz-Leung , Wong Wilfred Hing-Sang , Yang Wanling , Lee Pamela P. , Tu Wenwei , Yang Xi-Qiang , Lau Yu Lung 
Published: July 2022

To address inborn errors of immunity (IEI) which were underdiagnosed in resource-limited regions, our centre developed and offered free genetic testing for the most common IEI by Sanger sequencing (SS) since 2001. With the establishment of The Asian Primary Immunodeficiency (APID) Network in 2009, the awareness and definitive diagnosis of IEI were further improved with collaboration among centres caring for IEI patients from East and Southeast Asia. We also started to use whole exome sequencing (WES) for undiagnosed cases and further extended our collaboration with centres from South Asia and Africa. With the increased use of Next Generation Sequencing (NGS), we have shifted our diagnostic practice from SS to WES. However, SS was still one of the key diagnostic tools for IEI for the past two decades. Our centre has performed 2,024 IEI SS genetic tests, with in-house protocol designed specifically for 84 genes, in 1,376 patients with 744 identified to have disease-causing mutations (54.1%). The high diagnostic rate after just one round of targeted gene SS for each of the 5 common IEI (X-linked agammaglobulinemia (XLA) 77.4%, Wiskott–Aldrich syndrome (WAS) 69.2%, X-linked chronic granulomatous disease (XCGD) 59.5%, X-linked severe combined immunodeficiency (XSCID) 51.1%, and X-linked hyper-IgM syndrome (HIGM1) 58.1%) demonstrated targeted gene SS should remain the first-tier genetic test for the 5 common X-linked IEI.