Prevalence of hypocalcaemia and its associated features in 22q11·2 deletion syndrome.

[22q11.2 deletion syndrome]

22 q 11 .2 deletion syndrome (22 q 11 .2 DS ) is a relatively common yet under-recognized genetic syndrome that may present with endocrine features . We aimed to address the factors that contribute to the high prevalence of hypocalcaemia .We investigated hypocalcaemia in a well-characterized sample of 138 adults with 22 q 11 .2 DS (65 m , 73 F ; mean age 34 .2 , SD 11 .8 , years ) using laboratory studies and lifelong medical records . Logistic regression modelling was used to identify features associated with lifetime prevalence of hypocalcaemia .Of the total sample , 111 (80 .4 %) had a lifetime history of hypocalcaemia . Eleven (84 .6 %) of 13 subjects with neonatal hypocalcaemia had documented recurrence of hypocalcaemia . Lifetime history of hypocalcaemia was associated with lifetime prevalence of hypoparathyroidism (P < 0 .0001 ) and hypothyroidism (P = 0 .04 ), as statistically independent factors . Hypomagnesaemia was associated with concurrent hypocalcaemic measurements , especially in the presence of concurrent hypoparathyroidism (P = 0 .02 ).The results suggest that , in addition to the major effect of hypoparathyroidism , hypothyroidism may play a role in hypocalcaemia in 22 q 11 .2 DS and that there is a high recurrence rate of neonatal hypocalcaemia . Hypomagnesaemia may contribute to hypocalcaemia by further suppressing parathyroid hormone (PTH ). Although further studies are needed , the findings support regular lifelong follow-up of calcium , magnesium , PTH and TSH levels in patients with 22 q 11 .2 DS . At any age , hypocalcaemia with hypoparathyroidism and /or hypothyroidism may suggest a diagnosis of 22 q 11 .2 DS .