Macrocephaly is customarily diagnosed if head circumference is greater than two standard deviations (SDs) above the mean. Relative macrocephaly occurs if the measure is less than two SDs above the mean, but is disproportionately above that when ethnicity and stature are considered. Diagnosis can be determined in utero or can be determined within 18–24 months after birth in some cases where head circumference tends to stabilize in infants. Diagnosis in infants includes measuring the circumference of the child's head and comparing how significant it falls above the 97.5 percentile of children similar to their demographic. If falling above the 97.5th percentile then the patient will be checked to determine whether there is any intracranial pressure present and whether or not immediate surgery is needed. If immediate surgery is not needed then further testing will be done to determine whether the patient has either macrocephaly or benign macrocephaly. Diagnosis for macrocephaly involves the comparison of the infant's head circumference to that of other infants of the same age and ethnicity. If a patient is suspected of having macrocephaly molecular testing will be used to confirm diagnosis. Symptoms vary on the cause of macrocephaly on the child and if the child has any other accompanying syndromes which will be determined through molecular testing. Benign or familial macrocephaly Benign macrocephaly can occur without reason or be inherited by one or both parents (in which it is considered benign familial macrocephaly and is considered megalencephaly form of macrocephaly). Diagnoses for familial macrocephaly is determined by measuring the head circumference of both parents and comparing it to the child's. Benign and familial macrocephaly is not associated with neurological disorders. While benign and familial macrocephaly does not result in neurological disorders, neurodevelopment will still be assessed. Although neurological disorders do not occur, temporary symptoms of benign and familial macrocephaly include: developmental delay, epilepsy, and mild hypotonia. Neurodevelopment is assessed for all cases and suspected cases of macrocephaly to determine whether and what treatments may be needed, and whether any other syndrome/s may be present or likely to develop.
symptom of Maroteaux–Lamy syndrome
symptom of Rotor syndrome
symptom of Tay–Sachs disease
symptom of Lesch–Nyhan syndrome
symptoms of Rotor syndrome
symptom of Bannayan–Riley–Ruvalcaba syndrome
symptom of Andersen–Tawil syndrome
symptom of Scheuermann's disease