Types
An overview of types 1, 2, and 4 is presented below (type 3 is usually excluded from modern classifications):

Type 1: distal
Distal RTA (dRTA) is the classical form of RTA, being the first described. Distal RTA is characterized by a failure of H+ secretion into lumen of nephron by the alpha intercalated cells of the medullary collecting duct of the distal nephron.This failure of acid secretion may be due to a number of causes, and it leads to an inability to acidify the urine to a pH of less than 5.3. Because renal excretion is the primary means of eliminating H+ from the body, there is consequently a tendency towards acidemia. There is an inability to excrete H+ while K+ cannot be reclaimed by the cell, leading to acidemia (as H+ builds up in the body) and hypokalemia (as K+ cannot be reabsorbed by the alpha cell).This leads to the clinical features of dRTA; In other words, the intercalated cells apical H+/K+ antiporter is non-functional, resulting in proton retention and potassium excretion. Since calcium phosphate stones demonstrate a proclivity for deposition at higher pHs (alkaline), the substance of the kidney develops stones bilaterally; this does not occur in the other RTA types. Normal anion gap metabolic acidosis/acidemia
Hypokalemia, Hypocalcemia, Hyperchloremia
Urinary stone formation (related to alkaline urine, hypercalciuria, and low urinary citrate).
Although the patient may have a variety of other symptoms the diaphragmatic palsy confirmed by fluoroscopy or other means is the main criteria for diagnosis. This is usually confirmed with genetic testing looking for mutations in the IGHMBP2 gene. The patient can be misdiagnosed if the respiratory distress is mistaken for a severe respiratory infection or DMSA1 can be mistaken for SMA1 because their symptoms are so similar but the genes which are affected are different. This is why genetic testing is necessary to confirm the diagnosis of DMSA. Classification
DSMA1 was identified and classified as a sub-group of spinal muscular atrophies (SMA) in 1974. Currently, various classifications include DSMA1 among general spinal muscular atrophies or distal hereditary motor neuropathies, though the latter has been argued to be more correct. Treatment
There is no known cure to DSMA1, and care is primarily supportive. Patients require respiratory support which may include non-invasive ventilation or tracheal intubation. The child may also undergo additional immunisations and offered antibiotics to prevent respiratory infections. Maintaining a healthy weight is also important. Patients are at risk of undernutrition and weight loss because of the increased energy spent for breathing. Physical and occupational therapy for the child can be very effective in maintaining muscle strength.There is no published practice standard for the care in DSMA1, even though the Spinal Muscular Atrophy Standard of Care Committee has been trying to come to a consensus on the care standards for DSMA1 patients.