Below is a list of syndromes associated with macrocephaly that are noted in "". Macrocephaly and brain white matter abnormalities have also been observed. Absence of one copy is associated with macrocephaly and intellectual disability. Most mutations cause microcephaly while some specific changes appear to result in macrocephaly. A person with macrocephaly does not necessarily indicate that megalencephaly is also present. Benign and familial macrocephaly is not associated with neurological disorders. Babies with glutaric acidemia type 1 often are born with unusually large heads (macrocephaly). Macrocephaly is amongst the earliest signs of GA1. In "Secret Six" #6 (December 2006), Tetch claims to suffer from macrocephaly. Macrocephaly is observed in 84% of patients with Cowden syndrome. Macrocephaly is a "pivotal clinical sign" of many neurological diseases.