Israel Medical Association Journal

Background: Transcobalamin II is a serum transport protein for vitamin B₁₂. Small variations in TC-II[1] affinity were recently linked to a high homocysteine level and increased frequency of neural tube defects. Complete absence of TC-II or total functional abnormality causes tissue vitamin B₁₂ deficiency resulting in a severe disease with megaloblastic anemia and immunologic and intestinal abnormalities in the first months of life. This condition was described in hereditary autosomal-recessive form. Low serum TC-II without any symptoms or clinical significance was noted in relatives of affected homozygotes.

Objectives: To study 23 members of a four-generation family with hereditary vitamin B₁₂ deficiency and neurologic disorders.

Methods: Thorough neurologic, hematologic and family studies were supplemented by transcobalamin studies in 20 family members.

Results: Partial TC-II deficiency was found in 19 subjects. Apo TC- II (free TC-II unbound to vitamin B₁₂) and total unsaturated B₁₂ binding capacity were low in all tested individuals but one, and holo TC-II (TC-II bound by vitamin B₁₂) was low in all family members. The presentation of the disease was chronic rather than acute. Early signs in children and young adults were dyslexia, decreased IQ, vertigo, plantar clonus and personality disorders. Interestingly, affected children and young adults had normal or slightly decreased serum vitamin B₁₂ levels but were not anemic. Low serum B₁₂ levels were measured in early adulthood. In mid-late adulthood megaloblastic anemia and subacute combined degeneration of the spinal cord were diagnosed. Treatment with B₁₂ injections resulted in a significant improvement. The pedigree is compatible with an autosomal-dominant transmission. This family study suggests a genetic heterogeneity of TC-II deficiency.

Conclusions: We report the first family with a hereditary transmitted condition of low serum TC-II (partial TC-II deficiency) associated with neurologic and mental manifestations in childhood. Partial TC-II deficiency may decrease the amount of stored cobalamin, resulting in increased susceptibility to impaired intestinal delivery of cobalamin and predisposing to clinically expressed megaloblastic anemia at a later age. Partial TC-II deficiency should be suspected in families with megaloblastic anemia and in individuals with neurologic and mental disturbances – despite normal serum vitamin B₁₂ levels. Low serum UBBC[2] and apo TC-II should confirm the diagnosis. Early vitamin B₁₂ therapy may prevent irreversible neurologic damage.

Background: The ear is the most frequent organ affected during an explosion. Recognition of possible damage to its auditory and vestibular components, and particularly the recovery time of the incurred damage, may help in planning the optimal treatment strategies for the otologic manifestations of blast injury and preventing deleterious consequences.   

Objective: To report the results of the oto-vestibular initial evaluation and follow-up of 17 survivors of a suicidal terrorist attack on a municipal bus.

Methods: These 17 patients underwent periodic ear inspections and pure tone audiometry for 6 months. Balance studies, consisting of electronystagmography (ENG) and computerized dynamic posturography (CDP) were performed at the first time possible.

Results: Complaints of earache, aural fullness and tinnitus resolved, whereas dizziness persisted in most of the patients. By the end of the follow-up, 15 (55.6%) of the eardrum perforations had healed spontaneously. Hearing impairment was detected in 33 of the 34 tested ears. Recovery of hearing was complete in 6 ears and partial in another 11. ENG and CDP were performed in 13 patients: 5 had abnormal results on CDP while the ENG was normal in all the patients. The vertigo in seven patients resolved in only one patient who was free of symptoms 1 month after the explosion.

Conclusion:  Exposure to a high powered explosion in a confined space may result in severe auditory and vestibular damage. Awareness of these possible ear injuries may prevent many of the deleterious consequences of such injuries.