Congenital optic nerve pit in trisomy 18.

The authors report the first case of trisomy 18 associated with a clinically detectable optic nerve pit. A female infant with a birth weight of 2,150 g was born by cesarean section to a healthy 40-year-old woman at 38 weeks of gestation. Trisomy 18 had been diagnosed by prenatal genetic testing. Ophthalmologic examination was remarkable for bilateral narrowed palpebral fissures with punctal agenesis, corectopic pupils without reaction to light, bilateral inferior peripapillary retinochoroidal hypopigmentation, and significant optic nerve cupping in the left eye with associated temporal optic nerve pit. It has generally been accepted that optic nerve pits are a congenital anomaly. However, the pathophysiological background of optic nerve pits remains unclear and controversial. This is the first clinical and photographic documentation of an optic nerve pit in a neonate and in Edwards syndrome.

Anderson's disease/chylomicron retention disease in a Japanese patient with uniparental disomy 7 and a normal SAR1B gene protein coding sequence.

BACKGROUND: Anderson's Disease (AD)/Chylomicron Retention Disease (CMRD) is a rare hereditary hypocholesterolemic disorder characterized by a malabsorption syndrome with steatorrhea, failure to thrive and the absence of chylomicrons and apolipoprotein B48 post-prandially. All patients studied to date exhibit a mutation in the SAR1B gene, which codes for an essential component of the vesicular coat protein complex II (COPII) necessary for endoplasmic reticulum to Golgi transport. We describe here a patient with AD/CMRD, a normal SAR1B gene protein coding sequence and maternal uniparental disomy of chromosome 7 (matUPD7). METHODS AND RESULTS: The patient, one of two siblings of a Japanese family, had diarrhea and steatorrhea beginning at five months of age. There was a white duodenal mucosa upon endoscopy. Light and electron microscopy showed that the intestinal villi were normal but that they had lipid laden enterocytes containing accumulations of lipid droplets in the cytoplasm and lipoprotein-size particles in membrane bound structures. Although there were decreased amounts in plasma of total- and low-density lipoprotein cholesterol, apolipoproteins AI and B and vitamin E levels, the triglycerides were normal, typical of AD/CMRD. The presence of low density lipoproteins and apolipoprotein B in the plasma, although in decreased amounts, ruled out abetalipoproteinemia. The parents were asymptomatic with normal plasma cholesterol levels suggesting a recessive disorder and ruling out familial hypobetalipoproteinemia. Sequencing of genomic DNA showed that the 8 exons of the SAR1B gene were normal. Whole genome SNP analysis and karyotyping revealed matUPD7 with a normal karyotype. In contrast to other cases of AD/CMRD which have shown catch-up growth following vitamin supplementation and a fat restricted diet, our patient exhibits continued growth delay and other aspects of the matUPD7 and Silver-Russell Syndrome phenotypes. CONCLUSIONS: This patient with AD/CMRD has a normal SAR1B gene protein coding sequence which suggests that factors other than the SAR1B protein may be crucial for chylomicron secretion. Further, this patient exhibits matUPD7 with regions of homozygosity which might be useful for elucidating the molecular basis of the defect(s) in this individual. The results provide novel insights into the relation between phenotype and genotype in these diseases and for the mechanisms of secretion in the intestine.

Neurosonographic diagnosis of thalamic/basal ganglia vasculopathy in trisomy 13--an important diagnostic aid.

We performed a retrospective review of all the infants diagnosed with trisomy 13 in our institution from 1982 to 1995 and evaluated the neurosonographic findings along with their clinical information and cytogenetic analysis. Nine babies were admitted with trisomy 13. Sonography of the head was performed on 4 patients, and demonstrated in all of them a linear, branching, echogenic pattern in the thalamus/basal ganglia. Doppler evaluation of the thalamus/basal ganglia was performed in 3 of the 4 cases and confirmed these linear echogenicities to be of vascular origin. This is the first study to evaluated the occurrence of this finding in a specific syndrome, namely trisomy 13.