Endocrine Abstracts

A 23 yr old lady was admitted with a generalized tonic clonic seizure in May 2016. Her corrected calcium was 1.47 mmol/l (2.05–2.6 mmol/l) She was initially treated with intravenous calcium gluconate and subsequently switched to oral calcium carbonate tablets and one alphacalcidol tablets once her calcium improved. The patient gave a history of a prior seizure in 2013. At this point she was not investigated for any electrolyte imbalances. She was initially treated with the antiepileptic leviteracetam but this was later stopped. On further history taking it was noted that the patient had a history of developmental delay – she walked at 1 year 9 months and started talking at 5 years of age. On examination she had dysmorphic facial features with a long face, low set ears and retrognathia. We suspected she might have DiGeorge syndrome and further investigations revealed the following:

PTH: 10 pg/ml (15–65 pg/ml)

Vitamin D: 27 (30–100 ng/ml)

Flow Cytometry:

CD3 (T Lymphocytes): 609 cells/l (723–2,737 cells/l)

CD4 (Helper/Inducer T lymphocytes): 418 cells/l (404–1612 cells/l)

CD8 (Suppressor/Cytotoxic T-Lymphocytes): 174 cells/l (220–1,129 cells/l)

CD3: 56% (56–86%)

CD4: 39% (33–58%)

CD8: 16% (13–39%)

CD4/CD8: 2.4 (1–3)

A 22q11.2 deletion de novo mutation was confirmed on genetic studies. A diagnosis of DiGeorge syndrome was reached as this female patient had a reduced number of CD3 T cells, a deletion of chromosome 22q and hypocalcaemia which required therapy. The patient remains well on one alphacalcidol 0.5 μg daily and calcium carbonate 2,500 mg daily. Calcium levels are currently regularly monitored at outpatients and are now within normal limits. 24-h urinary calcium excretion is also satisfactory. She was reviewed by a clinical immunologist who suggested to check serology for pneumococcal antibody, Haemophilus influenza B antibody and tetanus antibody which were all positive, indicating adequate immunity. DiGeorge syndrome is caused by gene deletion at chromosome 22 at location q11.2 The microdeletion causes disruption during the embryonic development of the heart, head and neck, thymus and parathyroids. This leads to a variety of different signs and symptoms such as characteristic facial features, cardiac abnormalities, thymic aplasia with immunodeficiency and parathyroid hypoplasia. In this case parathyroid hypoplasia led to life threatening hypocalcaemia causing seizures.