Madras motor neuron disease variant, clinical features of seven patients

A Madras Motor Neuron Disease Patient With Cerebellar Atrophy: A New Clinical Feature

A 34-year-old Chinese Han female complaining of general muscle weakness and wasting for 9 years. She was admitted for aggravation of her symptoms caused by respiratory distress. She also suffered from bulbar palsy. She had no hearing loss, visual problems, or cerebellar signs. Her parents had a consanguineous marriage, though there was no family history of these symptoms. Pure tone audiometric findings demonstrated no definite abnormality. Electromyography demonstrated neurogenic damage. Brain magnetic resonance imaging revealed cerebellar atrophy, dominantly in anterior lobe. Gene sequencing of whole gene exomes was negative. She was finally diagnosed with Madras motor neuron disease (MMND), a rare subtype of motor neuron disease. No definite therapy was available for MMND, and she died of respiratory tract infection 1 year later. Previous studies have shown that cerebellar signs are positive in 17.2% patients of MMND, but no case with cerebellar atrophy has been reported before. Thus, here we describe cerebellar atrophy as a new clinical feature of MMND.

Amyotrophic lateral sclerosis and motor neuron syndromes in Asia

While the past 2 decades have witnessed an increasing understanding of amyotrophic lateral sclerosis (ALS) arising from East Asia, particularly Japan, South Korea, Taiwan and China, knowledge of ALS throughout the whole of Asia remains limited. Asia represents >50% of the world population, making it host to the largest patient cohort of ALS. Furthermore, Asia represents a diverse population in terms of ethnic, social and cultural backgrounds. In this review, an overview is presented that covers what is currently known of ALS in Asia from basic epidemiology and genetic influences, through to disease characteristics including atypical phenotypes which manifest a predilection for Asians. With the recent establishment of the Pan-Asian Consortium for Treatment and Research in ALS to facilitate collaborations between clinicians and researchers across the region, it is anticipated that Asia and the Pacific will contribute to unravelling the uncertainties in ALS.

Madras motor neuron disease (MMND) is distinct from the riboflavin transporter genetic defects that cause Brown-Vialetto-Van Laere syndrome

Introduction

Madras motor neuron disease (MMND), MMND variant (MMNDV) and Familial MMND (FMMND) have a unique geographic distribution predominantly reported from Southern India. The characteristic features are onset in young, weakness and wasting of limbs, multiple lower cranial nerve palsies and sensorineural hearing loss. There is a considerable overlap in the phenotype of MMND with Brown–Vialetto–Van Laere syndrome (BVVL) Boltshauser syndrome, Nathalie syndrome and Fazio–Londe syndrome. Recently a number of BVVL cases and families have been described with mutations in two riboflavin transporter genes SLC52A2 and SLC52A3 (solute carrier family 52, riboflavin transporter, member 2 and 3 respectively).

Methods and results

We describe six families and four sporadic MMND cases that have been clinically characterized in detail with history, examination, imaging and electrophysiological investigations. We sequenced the SLC52A1, SLC52A2 and SLC52A3 in affected probands and sporadic individuals from the MMND series as well as the C9ORF72 expansion. No genetic defects were identified and the C9ORF72 repeats were all less than 10.

Conclusions

These data suggest that MMND is a distinct clinical subgroup of childhood onset MND patients where the known genetic defects are so far negative. The clinico-genetic features of MMND in comparison with the BVVL group of childhood motor neuron diseases suggest that these diseases are likely to share a common defective biological pathway that may be a combination of genetic and environmental factors.

Mitochondrial DNA variations in Madras motor neuron disease

Although the Madras motor neuron disease (MMND) was found three decades ago, its genetic basis has not been elucidated, so far. The symptom at onset was impaired hearing, upper limb weakness and atrophy. Since some clinical features of MMND overlap with mitochondrial disorders, we analyzed the complete mitochondrial genome of 45 MMND patients and found 396 variations, including 13 disease-associated, 2 mt-tRNA and 33 non-synonymous (16 MT-ND, 10 MT-CO, 3 MT-CYB and 4 MT-ATPase). A rare variant (m.8302A>G) in mt-tRNA(Leu) was found in three patients. We predict that these variation(s) may influence the disease pathogenesis along with some unknown factor(s).

Madras motor neuron disease (MMND): clinical description and survival pattern of 116 patients from Southern India seen over 36 years (1971-2007)

Madras motor neuron disease (MMND), MMND variant (MMNDV) and Familial MMND (FMMND) have a unique geographic distribution predominantly reported from Southern India. The characteristic features are onset in young, weakness and wasting of limbs, multiple lower cranial nerve palsies and sensorineural hearing loss. We describe the clinical features and survival pattern in 116 patients with Sporadic MMND, MMND variant and FMMND. A retrospective review of patients' medical records for clinical manifestations, electromyography, imaging, audiological and histopathology findings was performed. Over 36 years (1971 to 2007) 116 patients (men: 59; women: 57) particularly hailing from Southern India were seen. Mean age of onset was 15.8+/-7.9 years. Predominant initial manifestations were impaired hearing with wasting and weakness of distal limb muscles and pyramidal dysfunction. All patients had clinical and/or audiological evidence of hearing impairment. Patients with MMNDV in addition had optic atrophy. The overall mean survival duration was 334.9+/-27.9 months. Thus, Madras motor neuron disease is clinically a distinct entity with features of amyotrophic lateral sclerosis but with young age of onset and presence of auditory neuropathy. Studies to look for environmental and genetic basis of this intriguing disease are necessary to find the causation of this rare disorder.

Familial Madras motor neuron disease (FMMND): study of 15 families from southern India

Madras motor neuron disease (MMND) and Madras motor neuron disease variant (MMNDV) have an unique geographic distribution with concentration of majority of cases in the southern states of India. They have the characteristic features of onset in young, weakness and wasting of the limbs, multiple cranial nerve palsies particularly involving the 7th, 9th to 12th and sensorineural hearing impairment. In addition, all patients with MMNDV have bilateral optic atrophy. During the past 32 years, a total of 104 patients were diagnosed to have MMND and among these 25 patients with the familial form were further evaluated. In this report, we describe the clinical features of these 25 patients diagnosed to have familial Madras motor neuron disease (FMMND) or familial Madras motor neuron disease variant (FMMNDV), belonging to 15 families hailing from southern India. There were 10 patients diagnosed to have FMMND and 15 with FMMNDV. There were 14 males and 11 females with mean age at onset of 13.0+/-6.2 years and mean duration of illness of 73.6+/-74.0 months. Notably, the occurrence of MMNDV in the familial group (15 of 25 patients) was significantly more as compared to occurrence in the group with sporadic MMND (SMMND) [12 of 79 patients] (p=0.0002).

Pontobulbar palsy and neurosensory deafness (Brown-Vialetto-van Laere syndrome) with hyperintense brainstem nuclei on magnetic resonance imaging: new finding in three siblings

Three siblings (one boy and two girls) with Brown-Vialetto-van Laere syndrome are reported. A peculiar feature of onset with hearing loss in a patient with multiple cranial nerve palsies and a positive family history suggests this diagnosis. In our family, an autosomal recessive mode of inheritance was seen. In addition, we observed that early onset was associated with rapid deterioration and death. Optic nerve involvement and hyperintensity of the brainstem nuclei on magnetic resonance imaging (MRI) are two new features described in this report.