Hi!
I can understand your worries regarding your son. Persistence of ankle clonus of 5-10 beats in an infant beyond the first three months of life is usually abnormal. If it persists beyond eight months of life and there is no other neurological abnormality then it may be a sign of very minimal cerebral palsy. Otherwise some neurological symptoms may appear (however mild) as the child grows up. The cause may be cerebral palsy or other upper motor neuron disease--traumatic brain injury, multiple sclerosis etc. As of now it is best to observe the child and follow up monthly with the pediatrician and consult a pediatric neurologist. Hope this helps. Take care!
The medical advice given should not be considered a substitute for medical care provided by a doctor who can examine you. The advice may not be completely correct for you as the doctor cannot examine you and does not know your complete medical history. Hence this reply to your post should only be considered as a guiding line and you must consult your doctor at the earliest for your medical problem.