Reliable and powerful laboratory markers of cobalamin deficiency in the newborn: plasma and urinary methylmalonic acid

Background: Diagnosing cobalamin deficiency is critical, given the high prevalence of cobalamin deficiency particularly in developing countries. Measuring serum cobalamin levels is of limited diagnostic sensitivity, in other words its specificity and sensitivity are low. The present study investigated the changes in the levels of metabolic markers – plasma homocysteine, plasma methylmalonic acid (MMA) and urinary MMA – of cobalamin metabolism.

Methods: Plasma cobalamin and serum folic acid were studied in 206 pregnant women over the last four prenatal weeks. Plasma cobalamin, folic acid, homocysteine, MMA from umbilical cord blood and urinary MMA in newborns were studied.

Results: Plasma cobalamin values were low in 66% of the mothers. There was a positive correlation between maternal and neonatal plasma cobalamin values (r?=?0.72, p?<?0.001). B12 was strongly inversely associated with plasma MMA, urine MMA and plasma homocysteine. To predict cobalamin deficiency, sensitivities of plasma MMA, urinary MMA and homocysteine were 96.4%, 95.6% and 88.2%, respectively. And positive predictive values (PPV) were 96.2%, 96.9% and 86% for plasma MMA, urinary MMA and plasma homocysteine levels, respectively.

Conclusion: Plasma MMA and urinary MMA B12 are the most robust markers of cobalamin deficiency. As a non-invasive method, urinary MMA is a sensitive method in demonstrating cobalamin deficiency in the newborn.     

Repeated tissue expansions on split-thickness skin graft in a patient with neurocutaneous syndrome

Soft tissue expansion is a mechanical process that increases the surface area of local tissue available for reconstructive procedures. In most cases, adjacent tissue that matches the recipient site in color, texture, and hair-bearing quality is preferred for tissue expansion. In this particular case with neurocutaneous syndrome, the defects that resulted from removal of parts of a giant hairy nevus overlying the latissimus dorsi muscle bilaterally were grafted with a split-thickness skin graft. Two expanders were then placed under the latissimus dorsi muscles. After full expansion of the grafted area, some part of the remaining nevus surrounding the grafted area was removed and the defects were covered with the expanded skin graft obtained after deflation of the expanders. The expanders placed under the latissimus dorsi muscle in the first operation were reused in the second operation to obtain a second expansion of the skin graft. After the second expansion of the skin graft, the expanders were deflated and another portion of the remaining nevus surrounding the grafted area was removed. The resulting defects were again covered with the excess expanded skin graft. Although repeated expansion of the skin graft is a time-consuming and laborious process, it eliminates the need for taking repeated skin grafts; it decreases skin graft donor site morbidity; it decreases possible infectious complications of tissue expansion by decreasing the number of surgical interventions to the expander pocket; and it increases the aesthetic outcome by keeping all the surgical scars around the grafted area without extending them into healthy surrounding skin.     

Moyamoya syndrome associated with sickle cell trait in a child

Moyamoya syndrome is a chronic, progressive occlussion of cerebrovascular arteries that leads to the development of characteristic collateral vessels. It is usually accompanied with sickle cell disease and other hemoglobinopathies. We report a 7-year-old boy, who admitted to our clinic with headache, diagnosed as moyamoya syndrome associated with sickle cell trait. To date, two such cases have been reported in the literature. As far as we know, this patient is the first child reported.