To improve the understanding of clinical phenotype and genotype of ataxia telangiectasia-like disorder 1 (ATLD1). Clinical data of a child with ATLD1 were retrospectively analyzed and related literatures were reviewed. An 11-year-old female patient was admitted to the hospital for regression in motor and intelligence development for more than two years. Clinical features include positive findings in hand rotation test, Romberg's sign, and finger-nose test, weakly positive findings in heel-knee-tibia test and left ankle clonus, other findings are grade IV muscle strength in all four limbs, poor coordination, and body swaying from side to side during walking. Two variants in MRE11 gene, c.728G>C and c.68G>C, were found by whole genome sequencing, which have not been reported. Diagnosis of ATLD was made, and rehabilitation with electronic biofeedback, low-frequency pulses, joint release training, traction, occupational therapy, hand function training, and exercise classes were ineffective. There are many causes of motor developmental delay and intellegence delay in children. Timely genetic testing helps early confirmed diagnosis. Guided prenatal counseling and diagnosis helps to avoid over-treatment and birth defects.