Spinal muscular atrophy with lower extremity predominance 2B explained

Synonyms:	Lower extremity-predominant spinal muscular atrophy type 2B, SMALED2B
Prognosis:	Life limiting
Diagnosis:	Molecular test
Causes:	Mutations in BICD2 gene
Duration:	Lifetime
Onset:	Infancy
Symptoms:	Generalised severe hypotonia at birth
Field:	Neurology

Spinal muscular atrophy with lower extremity predominance 2B (SMALED2B) is a rare neuromuscular disorder characterised by generalised muscle weakness.

Indications

Decreased foetal movement is apparent already before birth. The child is born with a generalised muscle weakness (hypotonia) and contractures resembling arthrogryposis multiplex congenita, respiratory insufficiency, and sometimes facial deformations.^[1] The disorder is frequently fatal in early childhood.

Cause

The disease is caused by a mutation in the BICD2 gene and is passed on in an autosomal dominant manner. There is no known cure to SMALED2B.

See also

• Spinal muscular atrophies
• Spinal muscular atrophy with lower extremity predominance 1
• Spinal muscular atrophy with lower extremity predominance 2A

Notes and References

1. Koboldt. Daniel C.. Kastury. Rama D.. Waldrop. Megan A.. Kelly. Benjamin J.. Mosher. Theresa Mihalic. McLaughlin. Heather. Corsmeier. Don. Slaughter. Jonathan L.. Flanigan. Kevin M.. McBride. Kim L.. Mehta. Lakshmi. 2018. In-frame de novo mutation in BICD2 in two patients with muscular atrophy and arthrogryposis. Cold Spring Harbor Molecular Case Studies. en. 4. 5. a003160. 10.1101/mcs.a003160. 2373-2865. 6169820. 30054298.