Linear nevus sebaceous syndrome: megalencephaly and heterotopic gray matter.

A 3-month-old white male with linear nevus sebaceous syndrome (LNSS), facial deformities, brain malformations, and cortical blindness is presented. Facial deformities included left ear hypertrophy and a left-sided hamartomatous neck mass. Magnetic resonance imaging suggested that a central nervous system (CNS) abnormality, involving gray and white matter, should be linked with LNSS. Magnetic resonance imaging was more useful than computed tomography in demonstrating the full spectrum of CNS anomalies, including unilateral lissencephaly, a paucity of white matter, excessive and heterotopic gray matter, apparent left schizencephaly, and unilateral left colpocephaly (dilation of atrium and posterior horn of lateral ventricle). Postmortem examination revealed left hemisphere megalencephaly with a dilated posterior horn of the lateral ventricle. The impressive gray matter heterotopias likely were the source of the patient's seizures and perhaps the ultimate cause of death. Megalencephaly and other deviations of neuronal migration should be considered as a dramatic component of LNSS.

Transient ventilatory response to CO2 as a function of sleep state in full-term infants.

The influence of sleep state on the transient (i.e., initial 60 s) and steady-state ventilatory responses to 2% CO2 inhalation was studied in 19 healthy full-term infants. A nasal mask pneumotachometer was used to measure ventilation and end-tidal CO2 partial pressure (PCO2) and enabled abrupt changes in the inspired gas concentration to be made. The magnitude of the change in minute ventilation for both the transient and steady-state responses to CO2 was not statistically different between active (AS) and quiet (QS) sleep. Nonetheless the greater variability in minute ventilation during AS compared with QS continued throughout the period of CO2 inhalation and was associated with a more variable change in ventilation in the individual infants during AS. There was a greater increase in end-tidal PCO2 over the first 60 s during AS (3.3 +/- 0.3 vs. 2.6 +/- 0.2 Torr, in AS and QS, respectively, P less than 0.03). This may indicate a smaller initial increase in alveolar ventilation, relative to CO2 delivery to the lungs, in response to CO2 inhalation during AS. Asynchronous chest wall movements were more common during AS than QS (P less than 0.005) and did not change with CO2. The inconsistent transient ventilatory response to CO2 during AS compared with QS may be important in the behavior of infants to spontaneous episodes of hypercapnia occurring during AS.

Histidinemia. A case with resolution of myoclonic seizures after treatment with a low-histidine diet.

An infant with histidinemia had a myoclonic seizure disorder that was unresponsive to therapy with anticonvulsants. The seizures stopped promptly after a histidine-restricted diet was instituted. This case suggests that in some individuals with histidinemia, diet therapy may be effective. It is not known what distinguishes this case from previously reported cases in which diet therapy was not effective.