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Severe X-linked myotubular myopathy(CNMX)

MedGen UID:
98374
Concept ID:
C0410203
Congenital Abnormality
Synonyms: CNMX; MYOPATHY, CENTRONUCLEAR, 1; MYOTUBULAR MYOPATHY 1; Myotubular myopathy, X-linked; X-linked centronuclear myopathy
Modes of inheritance:
X-linked recessive inheritance
MedGen UID:
375779
Concept ID:
C1845977
Finding
Sources: HPO, OMIM, Orphanet
A mode of inheritance that is observed for recessive traits related to a gene encoded on the X chromosome. In the context of medical genetics, X-linked recessive disorders manifest in males (who have one copy of the X chromosome and are thus hemizygotes), but generally not in female heterozygotes who have one mutant and one normal allele.
X-linked recessive inheritance (HPO, OMIM, Orphanet)
SNOMED CT: X-linked centronuclear myopathy (46804001); Severe x-linked myotubular myopathy (46804001)
 
Gene (location): MTM1 (Xq28)
OMIM®: 310400
Orphanet: ORPHA596

Disease characteristics

Excerpted from the GeneReview: X-Linked Centronuclear Myopathy
X-linked centronuclear myopathy (XLCNM) (also known as myotubular myopathy [MTM]) is characterized by muscle weakness that ranges from severe to mild. Severe (classic) XLCNM presents prenatally with polyhydramnios and decreased fetal movement and in newborns with weakness, hypotonia, and respiratory distress. Affected males have significantly delayed motor milestones and most fail to achieve independent ambulation. Weakness is profound and often involves facial and extraocular muscles. Respiratory failure is nearly uniform, with most affected individuals requiring 24-hour ventilatory assistance. A minority of males with severe XLCNM die in infancy. Males with moderate XLCNM achieve motor milestones more quickly than males with the severe form; about 40% require no ventilator support or intermittent support. Males with mild XLCNM may require ventilatory support only in the newborn period; they have minimally delayed motor milestones, are able to walk, and may lack myopathic facies. The muscle disease of XLCNM is not obviously progressive. Female carriers of XLCNM are generally asymptomatic, although rare manifesting heterozygotes have been described. [from GeneReviews]
Authors:
Soma Das  |  James Dowling  |  Christopher R Pierson   view full author information

Additional description

From GHR
X-linked myotubular myopathy is a condition that primarily affects muscles used for movement (skeletal muscles) and occurs almost exclusively in males. People with this condition have muscle weakness (myopathy) and decreased muscle tone (hypotonia) that are usually evident at birth.The muscle problems in X-linked myotubular myopathy impair the development of motor skills such as sitting, standing, and walking. Affected infants may also have difficulties with feeding due to muscle weakness. Individuals with this condition often do not have the muscle strength to breathe on their own and must be supported with a machine to help them breathe (mechanical ventilation). Some affected individuals need breathing assistance only periodically, typically during sleep, while others require it continuously. People with X-linked myotubular myopathy may also have weakness in the muscles that control eye movement (ophthalmoplegia), weakness in other muscles of the face, and absent reflexes (areflexia).In X-linked myotubular myopathy, muscle weakness often disrupts normal bone development and can lead to fragile bones, an abnormal curvature of the spine (scoliosis), and joint deformities (contractures) of the hips and knees. People with X-linked myotubular myopathy may have a large head with a narrow and elongated face and a high, arched roof of the mouth (palate). They may also have liver disease, recurrent ear and respiratory infections, or seizures.Because of their severe breathing problems, individuals with X-linked myotubular myopathy usually survive only into early childhood; however, some people with this condition have lived into adulthood.X-linked myotubular myopathy is a member of a group of disorders called centronuclear myopathies. In centronuclear myopathies, the nucleus is found at the center of many rod-shaped muscle cells instead of at either end, where it is normally located.  https://ghr.nlm.nih.gov/condition/x-linked-myotubular-myopathy

Clinical features

Arachnodactyly
MedGen UID:
2047
Concept ID:
C0003706
Congenital Abnormality
An abnormal bone development that is characterized by extra long and slender hands and fingers, such that the clenched thumb extends beyond the ulnar side of the hand. Arachnodactyly can include feet and toes. Arachnodactyly has been associated with several gene mutations and syndromes.
Slender toe
MedGen UID:
866814
Concept ID:
C4021168
Finding
Digits are disproportionately narrow (reduced girth) for the hand/foot size or build of the individual.
Birth length greater than 97th percentile
MedGen UID:
326443
Concept ID:
C1839271
Finding
Decreased liver function
MedGen UID:
39248
Concept ID:
C0086565
Pathologic Function
Elevations of the levels of SGOT and SGPT in the serum. SGOT (serum glutamic oxaloacetic transaminase) and SGPT (serum glutamic pyruvic transaminase) are transaminases primarily found in the liver and heart and are released into the bloodstream as the result of liver or heart damage. SGOT and SGPT are used clinically mainly as markers of liver damage.
Neonatal respiratory distress
MedGen UID:
163106
Concept ID:
C0852283
Disease or Syndrome
Respiratory difficulty as newborn.
Respiratory failure requiring assisted ventilation
MedGen UID:
870821
Concept ID:
C4025279
Finding
Flexion contracture
MedGen UID:
3227
Concept ID:
C0009917
Acquired 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.
Diaphragmatic eventration
MedGen UID:
8359
Concept ID:
C0011981
Congenital Abnormality
A congenital abnormality characterized by the elevation of the DIAPHRAGM dome. It is the result of a thinned diaphragmatic muscle and injured PHRENIC NERVE, allowing the intra-abdominal viscera to push the diaphragm upward against the LUNG.
Neck muscle weakness
MedGen UID:
66808
Concept ID:
C0240479
Finding
Decreased strength of the neck musculature.
Facial paralysis
MedGen UID:
98103
Concept ID:
C0427055
Sign or Symptom
Complete loss of ability to move facial muscles innervated by the facial nerve (i.e., the seventh cranial nerve).
Generalized muscle weakness
MedGen UID:
155433
Concept ID:
C0746674
Sign or Symptom
Generalized weakness or decreased strength of the muscles, affecting both distal and proximal musculature.
Severe muscular hypotonia
MedGen UID:
326544
Concept ID:
C1839630
Finding
A severe degree of muscular hypotonia characterized by markedly reduced muscle tone.
Arachnodactyly
MedGen UID:
2047
Concept ID:
C0003706
Congenital Abnormality
An abnormal bone development that is characterized by extra long and slender hands and fingers, such that the clenched thumb extends beyond the ulnar side of the hand. Arachnodactyly can include feet and toes. Arachnodactyly has been associated with several gene mutations and syndromes.
Flexion contracture
MedGen UID:
3227
Concept ID:
C0009917
Acquired 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.
Slender toe
MedGen UID:
866814
Concept ID:
C4021168
Finding
Digits are disproportionately narrow (reduced girth) for the hand/foot size or build of the individual.
Macrocephaly
MedGen UID:
745757
Concept ID:
C2243051
Finding
Macrocephaly refers to an abnormally enlarged head inclusive of the scalp, cranial bones, and intracranial contents. Macrocephaly may be due to megalencephaly (true enlargement of the brain parenchyma), and the 2 terms are often used interchangeably in the genetic literature (reviews by Olney, 2007 and Williams et al., 2008). Autosomal recessive macrocephaly/megalencephaly syndrome is characterized by an enlarged cranium apparent at birth or in early childhood. Affected individuals have intellectual disability and may have dysmorphic facial features resulting from the macrocephaly (summary by Alfaiz et al., 2014).
Flexion contracture
MedGen UID:
3227
Concept ID:
C0009917
Acquired 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.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
Follow this link to review classifications for Severe X-linked myotubular myopathy in Orphanet.

Professional guidelines

PubMed

Biancalana V, Beggs AH, Das S, Jungbluth H, Kress W, Nishino I, North K, Romero NB, Laporte J
Eur J Hum Genet 2012 Oct;20(10) Epub 2012 May 23 doi: 10.1038/ejhg.2012.91. PMID: 22617344Free PMC Article

Recent clinical studies

Prognosis

Tyson RW, Ringel SP, Manchester DK, Shikes RH, Goodman SI
Pediatr Pathol 1992 Jul-Aug;12(4):535-43. PMID: 1409152

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