Talk to Pediatrician on Unable To Suck & Swallow

Assalam-o-Alaikum, My daughter born 3 months back (18th Jun 2018) in Riyadh, Saudi Arabia. In first few hours, doctors found that baby’s moment is well below than a normal infant. At the same time, they found that baby is unable to suck and swallow. Hence, doctors believe that baby is suffering from central Hypotonia. And Doctors recommended NG tube to feed baby, which we are still using even after 3 months. In parallel, a series of tests (Attached) has been conducted on baby including (Brain MRI, Brain Ultrasound, Brain CT, CSF for Cytology, Lactats – CSF, new born screening, Creatine Kinase, methylation analysis prader-willi syndrome) and all test reports are normal, and doctors are unable to find the cause of Hypotonia. As a next step of investigation, doctors are recommending to conduct “Whole Exome Sequencing test”, which is underway now. I would like to know if this investigation is going on the right direction? and any help on solving baby’s suck and swallow problem?