U.S. flag

An official website of the United States government

Format

Send to:

Choose Destination

Myopathy, reducing body, X-linked, early-onset, severe(RBMX1A)

MedGen UID:
906731
Concept ID:
C4225423
Disease or Syndrome
Synonyms: RBMX1A; REDUCING BODY MYOPATHY, X-LINKED 1, SEVERE, WITH INFANTILE OR EARLY CHILDHOOD ONSET
 
Gene (location): FHL1 (Xq26.3)
 
Monarch Initiative: MONDO:0010414
OMIM®: 300717

Definition

Reducing-body myopathy (RBM) is a rare myopathy characterized pathologically by the presence of intracytoplasmic inclusion bodies strongly stained by menadione-linked alpha-glycerophosphate dehydrogenase (MAG) in the absence of substrate, alpha-glycerophosphate. The term 'reducing body' refers to the reducing activity of the inclusions to nitroblue tetrazolium (NBT) in the absence of substrate. This condition is also commonly associated with rimmed vacuoles and cytoplasmic bodies. The clinical features of RBM are variable; a severe form has onset in infancy or early childhood and results in severe disability or early death, and a less severe form has onset in late childhood or adulthood (RBMX1B; 300718) (summary by Liewluck et al., 2007 and Shalaby et al., 2009). [from OMIM]

Clinical features

From HPO
Areflexia
MedGen UID:
115943
Concept ID:
C0234146
Finding
Absence of neurologic reflexes such as the knee-jerk reaction.
Hyporeflexia
MedGen UID:
195967
Concept ID:
C0700078
Finding
Reduction of neurologic reflexes such as the knee-jerk reaction.
Loss of ambulation
MedGen UID:
332305
Concept ID:
C1836843
Finding
Inability to walk in a person who previous had the ability to walk.
Scoliosis
MedGen UID:
11348
Concept ID:
C0036439
Disease or Syndrome
The presence of an abnormal lateral curvature of the spine.
Proximal muscle weakness
MedGen UID:
113169
Concept ID:
C0221629
Finding
A lack of strength of the proximal muscles.
Flexion contracture
MedGen UID:
83069
Concept ID:
C0333068
Anatomical Abnormality
A flexion contracture is a bent (flexed) joint that cannot be straightened actively or passively. It is thus a chronic loss of joint motion due to structural changes in muscle, tendons, ligaments, or skin that prevents normal movement of joints.
Poor head control
MedGen UID:
322809
Concept ID:
C1836038
Finding
Difficulty to maintain correct position of the head while standing or sitting. Infant head lag is observed when the head seems to flop around or lags posteriorly behind the trunk. Several articles have maintained that head lag should be absent by age 3 to 4 months.
Increased variability in muscle fiber diameter
MedGen UID:
336019
Concept ID:
C1843700
Finding
An abnormally high degree of muscle fiber size variation. This phenotypic feature can be observed upon muscle biopsy.
Spinal rigidity
MedGen UID:
346721
Concept ID:
C1858025
Finding
Reduced ability to move the vertebral column with a resulting limitation of neck and trunk flexion.
Muscle fiber intracytoplasmic reducing inclusion bodies
MedGen UID:
1815072
Concept ID:
C5706166
Finding
Intracytoplasmic inclusions in myofibers that reduce nitro-blue tetrazolium (NBT) and thus stain strongly with the menadione-NBT stain.
Respiratory failure
MedGen UID:
257837
Concept ID:
C1145670
Disease or Syndrome
A severe form of respiratory insufficiency characterized by inadequate gas exchange such that the levels of oxygen or carbon dioxide cannot be maintained within normal limits.
Respiratory insufficiency due to muscle weakness
MedGen UID:
812797
Concept ID:
C3806467
Finding
Elevated circulating creatine kinase concentration
MedGen UID:
69128
Concept ID:
C0241005
Finding
An elevation of the level of the enzyme creatine kinase (also known as creatine phosphokinase (CK; EC 2.7.3.2) in the blood. CK levels can be elevated in a number of clinical disorders such as myocardial infarction, rhabdomyolysis, and muscular dystrophy.

Supplemental Content

Recent activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...