Malonic acid to methylmalonic acid ratio
The use of plasma rather than urine is recommended for determining the ratio of malonic acid to methylmalonic acid. Since even with an increase in sensitivity for malonic acid (MA), concentrations in urine samples can be so subtle that they are easily missed. In contrast, if only urinary methylmalonic acid (MAA) is used as the sole matrix, then CMAMMA due to ACSF3 may be misdiagnosed as classic methylmalonic acidemia. Also the calculation of the MA/MAA ratio in urine is not useful, because due to overlapping, healthy individuals cannot be clearly distinguished from CMAMMA affected individuals. Whereas, by calculating the MA/MMA ratio in plasma, a CMAMMA can be clearly distinguished from a classic methylmalonic acidemia. This is true for both, vitamin B12 responders and non-responders in methylmalonic acidemia.In CMAMMA due to ACSF3, methylamlonic acid levels exceed those of malonic acid. In contrast, in CMAMMA due to malonyl-CoA deficiency, the MMA/MA ratio is less than 1. Genetic testing
Extended carrier screening (ECS) in the course of fertility treatment can also identify carriers of mutations in the ACSF3 gene. Treatments
Dietary
One approach to reduce the accumulating amount of malonic acid and methylmalonic acid is diet. Here, a diet high in carbohydrate and low in protein has been shown to be best. Changes in malonic acid and methylmalonic acid excretion can be seen as early as 24-36 h after a change in diet. Bacteria-reducing measures
Another quantitatively significant source of malonic acid and methylmalonic acid, in addition to dietary protein intake, is bacterial fermentation.
Diastrophic dysplasia is an autosomal recessive dysplasia which affects cartilage and bone development. ("Diastrophism" is a general word referring to a twisting.) Diastrophic dysplasia is due to mutations in the SLC26A2 gene. Affected individuals have short stature with very short arms and legs and joint problems that restrict mobility. Signs and symptoms
This condition is also characterized by an unusual clubfoot with twisting of the metatarsals, inward- and upward-turning foot, tarsus varus and inversion adducted appearances. Furthermore, they classically present with scoliosis (progressive curvature of the spine) and unusually positioned thumbs (hitchhikers thumbs). About half of infants with diastrophic dysplasia are born with an opening in the roof of the mouth called a cleft palate. Swelling of the external ears is also common in newborns and can lead to thickened, deformed ears. The signs and symptoms of diastrophic dysplasia are similar to those of another skeletal disorder called atelosteogenesis, type 2; however diastrophic dysplasia tends to be less severe. Genetic
It is one of a spectrum of skeletal disorders caused by mutations in the SLC26A2 gene. The protein encoded by this gene is essential for the normal development of cartilage and for its conversion to bone. Cartilage is a tough, flexible tissue that makes up much of the skeleton during early development. Most cartilage is later converted to bone, but in adulthood this tissue continues to cover and protect the ends of bones and is present in the nose and external ears.