Identification of two novel homozygous nonsense mutations in TRAPPC9 in two unrelated consanguineous families with intellectual Disability from Iran

BACKGROUND: Pathogenic mutations in TRAPPC9 are associated with autosomal recessive Intellectual Disability (ID), a major public health issue that affects about 1–3% of children worldwide. METHOD: Clinical evaluation, magnetic resonance imaging, peripheral blood karyotype, Multiplex ligation‐dependent probe amplification (MLPA), array CGH, and whole‐exome sequencing were used to characterize etiology in three patients from two unrelated consanguineous families of Iranian descent with intellectual disability. RESULTS: Whole‐exome sequencing showed two novel homozygous nonsense mutations (c.937C>T) in exon 3 and (c.3103C>T) in exon 19 of TRAPPC9 (NM_031466.7) in two unrelated consanguineous families. CONCLUSION: The two novel variants found in TRAPPC9 caused truncated protein and clinical manifestations such as ID, developmental delay, microcephaly, and brain abnormalities in three patients.