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Combined oxidative phosphorylation defect type 26(PNSED)

MedGen UID:
1799164
Concept ID:
C5567741
Disease or Syndrome
Synonyms: Combined oxidative phosphorylation deficiency 26; PERIPHERAL NEUROPATHY WITH VARIABLE SPASTICITY, EXERCISE INTOLERANCE, AND DEVELOPMENTAL DELAY; PNSED
SNOMED CT: Combined oxidative phosphorylation defect type 26 (1173034002); COXPD26 - combined oxidative phosphorylation defect type 26 (1173034002)
Modes of inheritance:
Autosomal recessive inheritance
MedGen UID:
141025
Concept ID:
C0441748
Intellectual Product
Source: Orphanet
A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele).
 
Gene (location): TRMT5 (14q23.1)
 
Monarch Initiative: MONDO:0014684
OMIM®: 616539
Orphanet: ORPHA477684

Definition

Peripheral neuropathy with variable spasticity, exercise intolerance, and developmental delay (PNSED) is an autosomal recessive multisystemic disorder with highly variable manifestations, even within the same family. Some patients present in infancy with hypotonia and global developmental delay with poor or absent motor skill acquisition and poor growth, whereas others present as young adults with exercise intolerance and muscle weakness. All patients have signs of a peripheral neuropathy, usually demyelinating, with distal muscle weakness and atrophy and distal sensory impairment; many become wheelchair-bound. Additional features include spasticity, extensor plantar responses, contractures, cerebellar signs, seizures, short stature, and rare involvement of other organ systems, including the heart, pancreas, and kidney. Biochemical analysis may show deficiencies in mitochondrial respiratory complex enzyme activities in patient tissue, although this is not always apparent. Lactate is frequently increased, suggesting mitochondrial dysfunction (Powell et al., 2015; Argente-Escrig et al., 2022). For a discussion of genetic heterogeneity of combined oxidative phosphorylation deficiency, see COXPD1 (609060). [from OMIM]

Clinical features

From HPO
Exercise intolerance
MedGen UID:
603270
Concept ID:
C0424551
Finding
A functional motor deficit where individuals whose responses to the challenges of exercise fail to achieve levels considered normal for their age and gender.
Glycosuria
MedGen UID:
42267
Concept ID:
C0017979
Finding
An increased concentration of glucose in the urine.
Renal tubular dysfunction
MedGen UID:
57484
Concept ID:
C0151747
Disease or Syndrome
Abnormal function of the renal tubule. The basic functional unit of the kidney, the nephron, consists of a renal corpuscle attached to a renal tubule, with roughly 0.8 to 1.5 nephrons per adult kidney. The functions of the renal tubule include reabsorption of water, electrolytes, glucose, and amino acids and secretion of substances such as uric acid.
2-3 toe syndactyly
MedGen UID:
1645640
Concept ID:
C4551570
Congenital Abnormality
Syndactyly with fusion of toes two and three.
Hypertrophic cardiomyopathy
MedGen UID:
2881
Concept ID:
C0007194
Disease or Syndrome
Hypertrophic cardiomyopathy (HCM) is defined by the presence of increased ventricular wall thickness or mass in the absence of loading conditions (hypertension, valve disease) sufficient to cause the observed abnormality.
Failure to thrive
MedGen UID:
746019
Concept ID:
C2315100
Disease or Syndrome
Failure to thrive (FTT) refers to a child whose physical growth is substantially below the norm.
Cirrhosis of liver
MedGen UID:
7368
Concept ID:
C0023890
Disease or Syndrome
A chronic disorder of the liver in which liver tissue becomes scarred and is partially replaced by regenerative nodules and fibrotic tissue resulting in loss of liver function.
Nausea and vomiting
MedGen UID:
45015
Concept ID:
C0027498
Sign or Symptom
Nausea is a commonly encountered symptom that has been defined as an unpleasant painless subjective feeling that one will imminently vomit. Vomiting has been defined as the forceful expulsion of the contents of the stomach, duodenum, or jejunum through the oral cavity. While nausea and vomiting are often thought to exist on a temporal continuum, this is not always the case. There are situations when severe nausea may be present without emesis and less frequently, when emesis may be present without preceding nausea.
Feeding difficulties
MedGen UID:
65429
Concept ID:
C0232466
Finding
Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it.
Exocrine pancreatic insufficiency
MedGen UID:
75647
Concept ID:
C0267963
Disease or Syndrome
Impaired function of the exocrine pancreas associated with a reduced ability to digest foods because of lack of digestive enzymes.
Malabsorption
MedGen UID:
811453
Concept ID:
C3714745
Finding
Impaired ability to absorb one or more nutrients from the intestine.
Spasticity
MedGen UID:
7753
Concept ID:
C0026838
Sign or Symptom
A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes.
Peripheral neuropathy
MedGen UID:
18386
Concept ID:
C0031117
Disease or Syndrome
Peripheral neuropathy is a general term for any disorder of the peripheral nervous system. The main clinical features used to classify peripheral neuropathy are distribution, type (mainly demyelinating versus mainly axonal), duration, and course.
Babinski sign
MedGen UID:
19708
Concept ID:
C0034935
Finding
Upturning of the big toe (and sometimes fanning of the other toes) in response to stimulation of the sole of the foot. If the Babinski sign is present it can indicate damage to the corticospinal tract.
Tremor
MedGen UID:
21635
Concept ID:
C0040822
Sign or Symptom
An unintentional, oscillating to-and-fro muscle movement about a joint axis.
Hyperreflexia
MedGen UID:
57738
Concept ID:
C0151889
Finding
Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles.
Global developmental delay
MedGen UID:
107838
Concept ID:
C0557874
Finding
A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.
Hyporeflexia
MedGen UID:
195967
Concept ID:
C0700078
Finding
Reduction of neurologic reflexes such as the knee-jerk reaction.
Poor speech
MedGen UID:
341172
Concept ID:
C1848207
Finding
Irritability
MedGen UID:
397841
Concept ID:
C2700617
Mental Process
A proneness to anger, i.e., a tendency to become easily bothered or annoyed.
Delayed CNS myelination
MedGen UID:
867393
Concept ID:
C4021758
Anatomical Abnormality
Delayed myelination in the central nervous system.
Brain atrophy
MedGen UID:
1643639
Concept ID:
C4551584
Disease or Syndrome
Partial or complete wasting (loss) of brain tissue that was once present.
Elevated hemoglobin A1c
MedGen UID:
892798
Concept ID:
C4073162
Finding
An increased concentration of hemoglobin A1c (HbA1c), which is the product of nonenzymatic attachment of a hexose molecule to the N-terminal amino acid of the hemoglobin molecule. This reaction is dependent on blood glucose concentration, and therefore reflects the mean glucose concentration over the previous 8 to 12 weeks. The HbA1c level provides a better indication of long-term glycemic control than one-time blood or urinary glucose measurements.
Hypertonia
MedGen UID:
10132
Concept ID:
C0026826
Finding
A condition in which there is increased muscle tone so that arms or legs, for example, are stiff and difficult to move.
Hypotonia
MedGen UID:
10133
Concept ID:
C0026827
Finding
Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist.
Muscle weakness
MedGen UID:
57735
Concept ID:
C0151786
Finding
Reduced strength of muscles.
Difficulty standing
MedGen UID:
69136
Concept ID:
C0241237
Sign or Symptom
Cytochrome C oxidase-negative muscle fibers
MedGen UID:
867360
Concept ID:
C4021724
Finding
An abnormally reduced activity of the enzyme cytochrome C oxidase in muscle tissue.
Dyspnea
MedGen UID:
3938
Concept ID:
C0013404
Sign or Symptom
Difficult or labored breathing. Dyspnea is a subjective feeling only the patient can rate, e.g., on a Borg scale.
Exertional dyspnea
MedGen UID:
68549
Concept ID:
C0231807
Sign or Symptom
Perceived difficulty to breathe that occurs with exercise or exertion and improves with rest.
Lactic acidosis
MedGen UID:
1717
Concept ID:
C0001125
Disease or Syndrome
An abnormal buildup of lactic acid in the body, leading to acidification of the blood and other bodily fluids.
Glucose intolerance
MedGen UID:
75760
Concept ID:
C0271650
Disease or Syndrome
Glucose intolerance (GI) can be defined as dysglycemia that comprises both prediabetes and diabetes. It includes the conditions of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) and diabetes mellitus (DM).
Narrow mouth
MedGen UID:
44435
Concept ID:
C0026034
Congenital Abnormality
Distance between the commissures of the mouth more than 2 SD below the mean. Alternatively, an apparently decreased width of the oral aperture (subjective).
Triangular face
MedGen UID:
324383
Concept ID:
C1835884
Finding
Facial contour, as viewed from the front, triangular in shape, with breadth at the temples and tapering to a narrow chin.
Blue sclerae
MedGen UID:
154236
Concept ID:
C0542514
Finding
An abnormal bluish coloration of the sclera.
Decreased activity of mitochondrial complex I
MedGen UID:
393796
Concept ID:
C2677650
Finding
A reduction in the activity of the mitochondrial respiratory chain complex I, which is part of the electron transport chain in mitochondria.
Decreased activity of mitochondrial complex III
MedGen UID:
460434
Concept ID:
C3149083
Finding
A reduction in the activity of the mitochondrial respiratory chain complex III, which is part of the electron transport chain in mitochondria.
Decreased activity of mitochondrial complex IV
MedGen UID:
866520
Concept ID:
C4020800
Finding
A reduction in the activity of the mitochondrial respiratory chain complex IV, which is part of the electron transport chain in mitochondria.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  

Recent systematic reviews

Dogan AE, Yuksel C, Du F, Chouinard VA, Öngür D
Neuropsychopharmacology 2018 Jul;43(8):1681-1690. Epub 2018 Mar 14 doi: 10.1038/s41386-018-0041-9. PMID: 29581538Free PMC Article

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