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Surfactant metabolism dysfunction, pulmonary, 4(SMDP4)

MedGen UID:
393858
Concept ID:
C2677877
Disease or Syndrome
Synonyms: CSF2RA DEFICIENCY; CSF2RA-Related Pulmonary Surfactant Metabolism Dysfunction; PAP DUE TO CSF2RA DEFICIENCY; PULMONARY ALVEOLAR PROTEINOSIS, CONGENITAL, 4; SMDP4
 
Gene (location): CSF2RA (Xp22.33;Yp11.2)
 
Monarch Initiative: MONDO:0010424
OMIM®: 300770

Definition

Pulmonary alveolar proteinosis (PAP) is a rare lung disorder in which surfactant-derived lipoproteins accumulate excessively within pulmonary alveoli, causing severe respiratory distress. Three forms of PAP have been described: hereditary (usually congenital), secondary, and acquired. Hereditary PAP is associated with mutations in the CSF2RA gene or in genes encoding surfactant proteins. Secondary PAP develops in conditions in which there are reduced numbers or functional impairment of alveolar macrophages and is associated with inhalation of inorganic dust (silica) or toxic fumes, hematologic malignancies, pharmacologic immunosuppression, infections, and impaired CSF2RB (138960) expression. Acquired PAP (610910), the most common form, usually occurs in adults and is caused by neutralizing autoantibodies to CSF2 (138960) (Martinez-Moczygemba et al., 2008). For a general phenotypic description and a discussion of genetic heterogeneity of congenital pulmonary surfactant metabolism dysfunction, see SMDP1 (265120). [from OMIM]

Additional description

From MedlinePlus Genetics
Surfactant dysfunction is a lung disorder that causes breathing problems. This condition results from abnormalities in the composition or function of surfactant, a mixture of certain fats (called phospholipids) and proteins that lines the lung tissue and makes breathing easy. Without normal surfactant, the tissue surrounding the air sacs in the lungs (the alveoli) sticks together (because of a force called surface tension) after exhalation, causing the alveoli to collapse. As a result, filling the lungs with air on each breath becomes very difficult, and the delivery of oxygen to the body is impaired.

The signs and symptoms of surfactant dysfunction can vary in severity. The most severe form of this condition causes respiratory distress syndrome in newborns. Affected babies have extreme difficulty breathing and are unable to get enough oxygen. The lack of oxygen can damage the baby's brain and other organs. This syndrome leads to respiratory failure, and most babies with this form of the condition do not survive more than a few months.

Less severe forms of surfactant dysfunction cause gradual onset of breathing problems in children or adults. Signs and symptoms of these milder forms are abnormally rapid breathing (tachypnea); low concentrations of oxygen in the blood (hypoxemia); and an inability to grow or gain weight at the expected rate (failure to thrive).

There are several types of surfactant dysfunction, which are identified by the genetic cause of the condition. One type, called SP-B deficiency, causes respiratory distress syndrome in newborns. Other types, known as SP-C dysfunction and ABCA3 deficiency, have signs and symptoms that range from mild to severe.  https://medlineplus.gov/genetics/condition/surfactant-dysfunction

Clinical features

From HPO
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.
Tachypnea
MedGen UID:
66669
Concept ID:
C0231835
Finding
Very rapid breathing.
Reduced forced vital capacity
MedGen UID:
337630
Concept ID:
C1846678
Finding
An abnormal reduction in the amount of air a person can expel following maximal inspiration.
Restrictive ventilatory defect
MedGen UID:
478856
Concept ID:
C3277226
Finding
A functional defect characterized by reduced total lung capacity (TLC) not associated with abnormalities of expiratory airflow or airway resistance. Spirometrically, a restrictive defect is defined as FEV1 (forced expiratory volume in 1 second) and FVC (forced vital capacity) less than 80 per cent. Restrictive lung disease may be caused by alterations in lung parenchyma or because of a disease of the pleura, chest wall, or neuromuscular apparatus.
Decreased DLCO
MedGen UID:
892993
Concept ID:
C4073175
Finding
Reduced ability of the lungs to transfer gas from inspired air to the bloodstream as measured by the diffusing capacity of the lungs for carbon monoxide (DLCO) test.
Reduced forced expiratory volume in one second
MedGen UID:
1687063
Concept ID:
C5139283
Finding
An abnormal reduction in the amount of air a person can forcefully expel in one second.
Pulmonary alveolar proteinosis
MedGen UID:
1763046
Concept ID:
C5400698
Finding
Accumulation of amorphous PAS-positive material in the space between alveolar macrophages, sometimes as condensed form (oval bodies) are typically found in alveolar proteinosis.
Ground-glass opacification
MedGen UID:
1779663
Concept ID:
C5539411
Finding
On chest radiographs, ground-glass opacity appears as an area of hazy increased lung opacity, usually extensive, within which margins of pulmonary vessels may be indistinct. On CT scans, it appears as hazy increased opacity of lung, with preservation of bronchial and vascular margins. It is caused by partial filling of airspaces, interstitial thickening (due to fluid, cells, and/or fibrosis), partial collapse of alveoli, increased capillary blood volume, or a combination of these, the common factor being the partial displacement of air. Ground-glass opacity is less opaque than consolidation, in which bronchovascular margins are obscured.

Recent clinical studies

Therapy

Suzuki T, Mayhew C, Sallese A, Chalk C, Carey BC, Malik P, Wood RE, Trapnell BC
Am J Respir Crit Care Med 2014 Jan 15;189(2):183-93. doi: 10.1164/rccm.201306-1039OC. PMID: 24279752Free PMC Article
Lachmann N, Happle C, Ackermann M, Lüttge D, Wetzke M, Merkert S, Hetzel M, Kensah G, Jara-Avaca M, Mucci A, Skuljec J, Dittrich AM, Pfaff N, Brennig S, Schambach A, Steinemann D, Göhring G, Cantz T, Martin U, Schwerk N, Hansen G, Moritz T
Am J Respir Crit Care Med 2014 Jan 15;189(2):167-82. doi: 10.1164/rccm.201306-1012OC. PMID: 24279725

Clinical prediction guides

Griese M, Bonella F, Costabel U, de Blic J, Tran NB, Liebisch G
Am J Respir Crit Care Med 2019 Oct 1;200(7):881-887. doi: 10.1164/rccm.201901-0086OC. PMID: 31002528

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