Table 1.
Human mutations decreasing SLC12A2 expression.
| Type of Mutation | Age | Effect of the Mutation on the Expression of SLC12A2 | Phenotype | Reference |
|---|---|---|---|---|
| 22 kb deletion affecting exons 2–7 of SLC12A2. chr5:127441491–127471419 |
5-year-old | complete absence of NKCC1 expression | multisystem disorder phenotype including intellectual disability | [47] |
| Biallelic loss-of-function variant in SLC12A2 c.2006-1G>A and c.1431delT |
2-month-old and 9-year-old |
NKCC1 deficiency | multisystem disorder phenotype including intellectual disability | [48] |
| Biallelic loss-of-function variant in SLC12A2 c.940C>T, p.Q314* and c.1536+4_1536+7del, p.? |
1-year-old | NKCC1 deficiency | multisystem disorder phenotype including intellectual disability | [49] |
| de novo mutations, single nucleotide variants (SNVs): g.127450305C>T, p.A327V (exon 4); g.12746683A>T, p.N376I (exon 5); g.127420201dup, p.H186fs16 (exon 1); g.127469897G>A, p.R410Q (exon 6); g.127503511G>A, p.W892* (exon 18); g.127466845G>C, p.A379L (exon 5). |
1-year-old, 3-year-old, 6-year-old, 9-year-old, 15-year-old, 21-year-old |
NKCC1 deficiency | Mild to severe intellectual disability or developmental delay. Some were diagnosed with autism and spastic paraparesis and some have had feeding difficulties | [51] |