3.1 Cohort description
Samples from the patients and their families (n = 100) were collected
from 10 hospitals located across China and included 44 females and 56
males. Of these, only one family member was affected in 89 families. The
mean [interquarter range] age of symptom onset of the probands was
32 months [7, 38.75], while the mean [interquarter range] age at
enrollment was 59 months [24.5, 87.75]. On average, it took more
than two years to receive a diagnosis after symptom onset. Fourteen
patients received inconclusive results from CMA and 62 received
nondiagnostic ES. A total of 24 patients received both CMA and ES prior
to enrollment (Figure 2a ). Patients presented with phenotypes
frequently associated with GDD/ID, such as abnormal brain MRI (n=56),
facial dysmorphism (n=30), and hypotonia (n=28). An overview of the
families is summarized in Table 1 . The detailed information of
each family is listed in Table S1 .