Summary

Primary intestinal hypomagnesemia with secondary hypocalcemia (HSH) or hypomagnesemic tetany is characterized by very low serum Mg2+ levels and normal renal Mg2+ excretion, associated with hypocalcemia. It is a severe disorder, which, if left untreated, is fatal. The cause of the disorder is believed to be a defect in the intestinal absorption of Mg2+. Patients usually present in the neonatal period and suffer from restlessness, tremor, tetany and overt seizures (Pronicka et al., 1991; Challa et al., 1995; Abdulrazzaq et al., 1989). Walder et al. (1997) found linkage to chromosome 9q in inbred Bedouin families suffering from HSH. Additionally, they identified a translocation patient (t:X-9q), defining the locus for hypomagnesemia with secondary hypocalcemia, HOMG, to 9q12-q22.2. With the availability of additional patient material, they were able to narrow down the 14-cM linkage interval to less than 1 cM, (Walder et al., 1999).Recently, mutations in TRPM6, a gene encoding a putative ion channel which belongs to the transient receptor potential family (TRP), were shown to cause HSH (Schlingmann et al., 2002, Walder et al., 2002) .

Expert reviewer(s)

• Pr N.V.A.M. [Nine] KNOERS
• Dr Iwan MEIJ