Hypothalamic disease in association with dysgenesis of the corpus callosum

Symptom-Related Differential Neuroimaging Biomarkers in Children with Corpus Callosum Abnormalities

We aimed to identify symptom-related neuroimaging biomarkers for patients with dysgenesis of the corpus callosum (dCC) by summarizing neurological symptoms reported in clinical evaluations and correlating them with retrospectively collected structural/diffusion brain magnetic resonance imaging (MRI) measures from 39 patients/controls (mean age 8.08 ± 3.98). Most symptoms/disorders studied were associated with CC abnormalities. Total brain (TB) volume was related to language, cognition, muscle tone, and metabolic/endocrine abnormalities. Although white matter (WM) volume was not related to symptoms studied, gray matter (GM) volume was related to cognitive, behavioral, and metabolic/endocrine disorders. Right hemisphere (RH) cortical thickness (CT) was linked to language abnormalities, while left hemisphere (LH) CT was linked to epilepsy. While RH gyrification index (GI) was not related to any symptoms studied, LH GI was uniquely related to cognitive disorders. Between patients and controls, GM volume and LH/RH CT were significantly greater in dCC patients, while WM volume and LH/RH GI were significantly greater in controls. TB volume and diffusion indices for tissue microstructures did not show differences between the groups. In summary, our brain MRI-based measures successfully revealed differential links to many symptoms. Specifically, LH GI abnormality can be a predictor for dCC patients, which is uniquely associated with the patients' symptom. In addition, patients with CC abnormalities had normal TB volume and overall tissue microstructures, with potentially deteriorated mechanisms to expand/fold the brain, indicated by GI.

Váradi syndrome (OFD VI) or Opitz trigonocephaly syndrome: overlapping manifestations in two cousins

We report on 2 cousins, offspring of consanguineous matings, with multiple congenital anomalies. Square face, frontal bossing with metopic ridge, small anteverted nose, flat nasal bridge, slanted palpebral fissures, and epicanthal folds contributed to an unusual appearance. Multiple bucco-alveolar frenula and notched inferior alveolar ridges were present at birth and one had a notched uvula and submucous cleft of the hard palate. Both had congenital heart anomalies, micropenis, and cryptorchidism. Persistence of Müllerian structures was documented at necropsy in one patient. The surviving patient was mentally retarded and had unilateral central hexadactyly and partial agenesis of the corpus callosum. Bulimia and episodic hyperthermia were attributed to hypothalamic dysfunction. Results of unstimulated endocrine studies and gonadotropin releasing hormone (GnRH), and human chorionic gonadotropin (HCG) stimulation tests were normal. The manifestations of the 2 patients overlap those reported in the OFD VI and Opitz trigonocephaly syndromes.

Osmotic and non-osmotic regulation of thirst and vasopressin secretion in patients with compulsive water drinking

OBJECTIVE

To examine the osmotic and non-osmotic regulation of thirst and AVP release in patients with compulsive water drinking.

DESIGN

A 2-hour intravenous infusion of hypertonic (855 mmol/l) sodium chloride solution, followed by a 2-hour drinking period.

PATIENTS

Seven patients with compulsive water drinking, seven patients with diabetes insipidus and seven healthy controls.

MEASUREMENTS

Plasma AVP, osmolality, sodium and haematocrit, thirst ratings on a visual analogue scale and the volume of water drunk in 2 hours following infusion.

RESULTS

Plasma AVP responses to osmotic stimulation, and non-osmotic inhibition by drinking, were normal in patients with compulsive water drinking. Basal thirst ratings were higher in compulsive water drinking than in either diabetes (P less than 0.001) or controls (P less than 0.001), despite lower basal plasma osmolalities. There was a significant rise in thirst ratings during saline infusion, which correlated closely with plasma osmolality, in all three groups, but the final thirst ratings were higher in compulsive water drinkers, who subsequently drank more water than in either diabetes insipidus (P less than 0.01) or controls (P less than 0.001). Drinking rapidly lowered thirst ratings in controls and diabetes insipidus before changes occurred in plasma osmolality, but remained elevated in patients with compulsive water drinking. Linear regression analysis defined a lower osmotic threshold for thirst in compulsive water drinking compared with controls or diabetes insipidus.

CONCLUSIONS

There are abnormalities of the osmotic stimulation and non-osmotic inhibition of thirst in compulsive water drinking, suggesting that the underlying defect is one of interpretation of osmotic and non-osmotic inputs. Measurement of thirst responses during hypertonic saline infusion and subsequent water drinking may provide useful diagnostic information in the differentiation of polyuric states.