Developmental neurogenetics and neuro-ophthalmology

Clinical spectrum of orbital and ocular abnormalities on fetal MRI

BACKGROUND

Fetal magnetic resonance imaging (MRI) may reveal sonographically occult ocular abnormalities. When discovered, acquired causes and genetic associations must be sought.

OBJECTIVE

We aim to evaluate a fetal cohort with orbit and/or globe malformations to determine whether there are imaging patterns that suggest the underlying cause.

MATERIALS AND METHODS

We searched all fetal MRI reports performed at an academic children's hospital over 9 consecutive years for orbit and/or globe abnormalities. Each positive exam and all follow-up MRIs were evaluated for interocular distance, globe size, shape and signal, and brain malformations. Genetic and clinical diagnoses were recorded from the medical record.

RESULTS

Seventy-six of 3,085 fetuses (2.5%) were diagnosed with ocular and/or globe abnormalities; 50% had postnatal follow-up MR exams, all confirming the fetal MRI findings. Ninety-two percent (70/76) had concurrent brain malformations. Sixty-seven percent (51/76) were diagnosed with an underlying disorder and 39% of these were genetically proven. The most common diagnoses with ocular globe abnormalities included CHARGE (coloboma of the eye, heart anomaly, choanal atresia, retardation and genital and ear anomalies) syndrome, trisomy 13 syndrome, dystroglycanopathy, holoprosencephaly and diencephalic-mesencephalic junction dysplasia. Genetic diagnoses were more likely with ocular globe abnormalities than isolated orbital abnormalities (P=0.04). Sixty-seven percent of fetuses with ocular calcifications, hemorrhage and/or lens abnormalities had potential maternal risk factors (P=0.03).

CONCLUSION

Malformed ocular globes are associated with brain malformations and genetic abnormalities. Ocular calcifications, hemorrhage and/or lens abnormalities may be associated with maternal risk factors. Genetic work-up should be considered when an ocular globe size or shape abnormality is detected.

[Septo-optic dysplasia (De Morsier's syndrome). About one case discovered during the pregnancy]

The authors report a case of septo-optic dysplasia discovered during the pregnancy without another abnormality. It's a rare cerebral abnormality that is characterized by an absence of septum pellucidum associated to a hypoplasia of ways and optic chiasm to variable degrees. Discovery is often made for adulthood. Future is extremely wide. It is determined with the arisen to different degrees of incapacity of Pituitary gland, psychomotor delay of variable intensity with mental deficiency, a visual confusion, and a confusion of the regulation of the temperature.

Septo-optic dysplasia plus: case report

Septo-optic dysplasia (SOD) is a syndrome composed by optic nerve and septum pellucidum dysgenesis. It has been classified into two subsets according to the embryogenesis and the neuropathological findings. Basically, the difference between these two groups is the presence or not of schizencephaly. The term SOD-Plus was recently proposed to describe SOD associated with cortical dysplasia. We report a 6-month-old female patient who presented absent visual fixation since 4 months of age and delayed psychomotor development. Neurological examination demonstrated spastic left hemiparesis and ophtalmological evaluation revealed bilateral optic disc hypoplasia. The head computed tomography (CT) scan showed absence of the septum pellucidum, ventricular asymmetry and schizencephaly. The magnetic resonance imaging (MRI) showed complete absence of the septum pellucidum associated to optic nerves and chiasma atrophy, schizencephaly and cortical dysplasia. The patient underwent an evoked potential examination with flash stimulation, which revealed bilateral absence of cortical evoked potential. She was referred to visual stimulation and physiotherapy. We emphasize the neuroimaging of this syndrome and stress the importance of the clinical investigation for patients with septum pellucidum dysgenesis on MRI or CT scans.