# May 2026

- Link: https://isnr.in/may-2026/
- Published: 2026-05-10T01:00:00+05:30
- Author: ISNR

## **CASE HISTORY**

A 5-year-old male child presented with complaints of recurrent generalized tonic–
clonic seizures and right-sided weakness ,predominantly involving the lower limb
along with anger outbursts and abnormal behaviour.

No history of fever, head trauma, vision loss, sensory loss, or headache.

No family history of seizure disorder or chronic neurological illness.

Birth history: Full-term normal vaginal delivery, birth weight 2.8 kg, no NICU stay

## **CASE CONTRIBUTED BY-**

**Dr Somya Gupta** – 3rd year Resident , Department of Radiodiagnosis, Kalinga Institute
of Medical Sciences , Bhubaneswar , Odisa

**Dr. Tapas kumar sahu** , Assistant Professor ,Department of Radiodiagnosis, Kalinga
Institute of Medical Sciences , Bhubaneswar , Odisa

**Dr. Basanta Manjari Swain** (HOD and Professor),Department of Radiodiagnosis, 
Kalinga Institute of Medical Sciences , Bhubaneswar , Odisa

![](https://isnr.in/wp-content/uploads/2026/05/Picture-1-1.png)

## **DESCRIPTION**

A and B  :Axial section of T2 sequence and axial section of FLAIR sequence shows
a diffuse, symmetrical  hyperintensity in  bilateral cerebral white matter including
subcortical U-fiberss. The white matter appears swollen, without significant volume
loss. Relative sparing of deep white matter

C: Axial FLAIR sequence shows few well-defined subcortical cysts  in the anterior
temporal lobes bilaterally

D: Axial section of Diffusion weighted sequence shows no abnormality

E: 3D Sagittal cube FLAIR FS  sequence shows relatively increased fronto-occipital
dimension, consistent with macrocephaly .

## **Diagnosis:Megalencephalic Leukoencephalopathy with Subcortical Cysts (MLC), also known as Van der Knaap disease**

**Background**

Megalencephalic Leukoencephalopathy with Subcortical Cysts (MLC), also known as 
Van der Knaap disease, is a rare inherited leukodystrophy .

It follows predominantly an autosomal recessive inheritance pattern

**Pathophysiology**

MLC is caused by mutations in:

MLC1 (≈75% cases)

HEPACAM (≈20% cases)

These genes encode proteins involved in astrocytic membrane function and regulation
of brain water and ion homeostasis.

Defective astrocyte function leads to: Impaired ion and water regulation leading
to white matter swelling

,vacuolation of myelin and Formation of subcortical cysts

The disease produces intramyelinic vacuolation rather than primary demyelination.

**Classical Features**

Macrocephaly (at birth or infancy; earliest and most consistent sign)

Delayed motor milestones

Early-onset seizures Mild early cognitive impairment with progressive Ataxia ,Spasticity,
Dysarthria

**Key MRI Findings**

Diffuse bilateral symmetric T2/FLAIR hyperintensity of subcortical and deep white
matter with corresponding T1 hypointensity

“Swollen white matter” appearance in early stage

Relative sparing of deep grey nuclei and brainstem

Subcortical cysts, predominantly in: Anterior temporal lobes (classical) and Frontoparietal
regions

Structures Typically Spared:

Basal ganglia

Thalami

Brainstem

Cerebellar white matter (early stage)

Diffusion Imaging: Usually no true diffusion restriction

**Differential Diagnosis-**

Canavan disease

Alexander disease

metachromatic leukodystrophy

others causes of megalencephaly

other leukoencephalopathies

**References**

1) Roy U, Joshi B, Ganguly G. Van der Knaap disease: a rare disease with atypical
features. BMJ Case Rep. 2015 Jul 22;2015:bcr2015209831. doi:10.1136/bcr-2015-209831.

2) Jhancy M, Al Homsi A, Chowdhury F, Hossain S, Ahamed R. Van der Knaap Disease(
Vanishing White Matter) – Unusual Presentation in a Neonate: A Case Report. Neurol
India. 2020 May-Jun;68(3):669-672. doi:10.4103/0028-3886.289018.

3) Das S, Dhibar T. Van der Knaap Disease: A Case Series Highlighting Clinical and
Radiological Features. Int J Anat Radiol Surg. 2025 Sep;14(5):RS01-RS03. doi:10.7860/
IJARS/2025/81128.3062