Hypothalamic hamartomas (HH) are rare, tumor-like malformations that occur during fetal development and are present at birth. The lesions usually do not change in size or spread to other locations. Both the type and severity of symptoms vary greatly among patients with hypothalamic hamartomas. Common symptoms include frequent gelastic seizures (spontaneous laughing, giggling and/or smirking) or dacrystic seizures (crying or grunting); developmental delays; and/or precocious puberty. Additional symptoms may include cognitive impairment; emotional and behavioral difficulties; and endocrine disturbances. These symptoms often start early in life but are frequently misdiagnosed. For some patients, endocrine (hormonal) disturbances such as central precocious puberty may be the only symptom. These patients can often be treated successfully with medications. For some, however, HH can be disabling. For those with HH and epilepsy, it is common for the disorder to progress and for different types of seizures to develop. The seizures associated with HH often cannot be well-controlled with the standard seizure medications. For some, additional treatment such as surgical removal, radiosurgery, or thermoablation may be indicated. Though hypothalamic hamartomas can occur in patients with certain genetic disorders (such as Pallister-Hall syndrome), the majority of cases are sporadic. The disease is congenital hypothalamic hamartoma syndrome (MONDO_0009436, a Monarch Disease Ontology entry). Also known as: Pallister-Hall-like syndrome, hamartoma of hypothalamus, hypothalamic hamartoma, hypothalamic hamartomas.