Endocrine Abstracts

Background: Septo-optic dysplasia (SOD), also known as de-Morsier syndrome, is a rare congenital disorder characterized by any combination of optic nerve hypoplasia, pituitary dysfunction and midline abnormalities of the brain. Clinical diagnosis requires the presence of at least two of the features. This disorder is equally prevalent in males and females, with a reported incidence of 1/10,000 live births. There is wide variation in the severity of the clinical features found. The most common endocrine anomaly is GH deficiency followed by ACTH and hypothyroidism.

Case report: A 37-year-old man with complaints of chronic back pain performed a CT scan of the spine which revealed diffuse bone demineralization. Later, a DEXA scan confirmed the diagnosis of osteoporosis. Subsequently, laboratory studies were requested and a low testosterone level was identified. No relevant medical or family history. He did not have children. He denied asthenia or decreased libido. The patient presented normal body hair distribution, no gynecomastia, normal testicular volume, 79 kg and 173 cm. An evaluation of the pituitary axis confirmed a low testosterone level (155 ng/dl), with gonadotropins in the low normal range (FSH 2.7 UI/l, LH 2.2 UI/l), suggestive of central hypogonadism. TSH, Prolactin, ACTH, Cortisol, GH and IGF-1 levels were within the reference range. A brain MRI was requested and reported an absent septum pellucidum, thinning of the corpus callosum and underdevelopment of optic nerves, features compatible with septo-optic dysplasia. He was referred to an ophthalmologist yet no macula or optic disc defects were found. The patient started testosterone replacement therapy with good biochemical response. After the diagnosis, he fathered a child with a diagnosis of Costello syndrome. Both parents were then referred to the Genetic Department.

Discussion: Patients with SOD are often diagnosed during infancy with visual, neurologic or endocrine defects. The few adult patients reported in the literature were diagnosed due to drug-resistant epilepsy. Our patient was asymptomatic, thus the diagnosis was made during a clinical investigation for secondary causes of osteoporosis. The sole endocrine anomaly found was gonadotropin deficiency, the least common reported. Nonetheless, the diagnosis of SOD was based on the classic features presented on MRI.

It is curious that father and child were diagnosed with rare congenital diseases. Costello syndrome is characterized by short stature, developmental delay and a characteristic facial appearance. Only about 350 affected individuals have been reported worldwide. As far as we know, no relation between the two diseases have been described.