I. Introduction
Holoprosencephaly (HPE) is a relatively rare developmental defect in the
median structures of the brain and face that results from impaired
cleavage of the embryonic forebrain. HPE occurs in 5–12/10,000 live
births (1), whereas an estimated 40 per 10 000 cases are seen among
human abortions indicating a high rate of fetal loss (2).
Patients with holoprosencephaly frequently display craniofacial
anomalies including midline facial clefts, cyclopia and nasal anomalies.
, They may also suffer from dysfunctions in the pituitary glands
presenting with diabetes insipidus (3).
Holoprosencephaly is etiologically diverse and can be perturbed by both
genetic and environmental causes, either individually or more likely in
combination with other congenital disorders. Approximately 65% of
holoprosencephaly appears to be sporadic and cannot be ascribed to any
known cause. Clinically, there is a nearly continuous spectrum of
malformations consistent with HPE which can manifest with variable
expressivity and/or penetrance, demonstrated by the segregation analysis
of familial cases (4).
Patients manifest a wide spectrum of clinical conditions and neurologic
dysfunction. Severity of symptoms correlates with the degree of
hemispheric nonseparation (5). Because the clinical spectrum of this
defect has been inadequately described in milder forms, we aim to report
an Iranian patient with holoprosencephaly with associated DI, which was
found to be refractory to conventional treatments.