Cortical reorganization in linear nevus sebaceous syndrome: a multimodality neuroimaging study

KRAS G12D mosaic mutation in a Chinese linear nevus sebaceous syndrome infant

BACKGROUND

Linear nevus sebaceous syndrome (LNSS) is a multisystem disorder that includes nevus sebaceous and central nervous system, ocular and skeletal anomalies. We report the first case of a KRAS G12D mosaic mutation in a patient diagnosed with LNSS.

CASE PRESENTATION

A 3-month-old female with a clinical diagnosis of LNSS presented with intermittent epilepsy. Her mother carefully collected a skin lesion sample from scratched-off scurf obtained from the patient's nails. DNA was extracted, and long-range PCR was performed to amplify the KRAS gene, which was then analyzed by next-generation sequencing. The results revealed the presence of a low-level heterozygous mutation in the KRAS gene (c.35C>T; p.G12D, 5 %).

CONCLUSIONS

These findings suggest that the KRAS somatic mosaic mutation in this patient may have caused her skin and eye lesions and epilepsy. With this correct diagnosis, the infant can be effectively treated.

Tc-99m HMPAO brain SPECT in linear nevus sebaceous syndrome

The authors present a case of linear nevus sebaceous syndrome (LNSS) with atrophy of bilateral frontotemporal areas of the brain, left cerebellum and hippocampus, and bilateral uncal dysplasia demonstrated by magnetic resonance imaging (MRI). Magnetic resonance angiography revealed bilateral internal carotid artery hypoplasia with absence of flow in the anterior and middle cerebral arteries. Tc-99m HMPAO brain SPECT demonstrated more areas of perfusion defects while MRI detected volume loss and gliosis in affected areas. Tc-99m HMPAO brain SPECT may be more useful for revealing absent or decreased perfusion areas of brain lesions than MRI in LNSS.