TABLE 1.
Clinical Findings in Affected Males in Two Families With SLC9A6 Mutations
| Family 1 (K8310) |
Family 2 (K9524) | ||||||
|---|---|---|---|---|---|---|---|
| III-9 | III-10 | III-12 | IV-1 | IV-4 | IV-6 | Propositus | |
| Age (years) | 35 | 4 | 28 | 14 | 611/12 | 12/12 | 6 |
| Birth weight, kg (centile) | 3.4 (35) | 3.3 (30) | 3.4 (35) | 2.5 (10) | 2.4 (5) | — | 3.3 (30) |
| Birth length, cm (centile) | 53.3 (90) | 53.3 (90) | 53.3 (90) | 49.5 (55) | — | — | 50.8 (60) |
| Birth OFC, cm (centile) | 36.8 (80) | 33 (5) | 33 (5) | 29.8 (<3) | — | — | 33 (5) |
| Height, cm (centile) | 168 (10) | 82.6 (<3) | — | 134 (<3) | 113 (5) | 75.3 (20) | 105.4 (3) |
| OFC, cm (centile) | 56 (35) | 44 (<3) | 48.5 (<3) | 49.5 (<3) | 46.5 (<3) | 41.4 (<3) | 46 (<3) |
| Frontal hair upsweepa | + | NR | + | + | + | + | o |
| Ocular palsy/strabismus | + | NR | + | + | + | + | + |
| Open mouth | + | NR | + | + | o | + | + |
| Drooling | + | NR | + | + | o | + | + |
| Prominent chin | + | NR | + | o | o | o | + |
| Elbow flexion/hand gazing | +/+ | NR | +/+ | +/+ | o/o | NR | o/o |
| Hypotonia | + | NR | + | + | + | + | + |
| Onset of seizures, mo | 23 | 18–24 | 7 | <24 | 15 | 16 | 6 |
| Speech | o | o | o | o | o | o | o |
| Walking | w/assistance | o | o | w/assistance | + | o | o |
| Involuntary movements | + | NR | o | + | o | o | o |
| Laughter/excessive smiling | + | NR | + | + | o | NR | o |
| Hyperreflexia | o | NR | o | + | o | o | o |
| Clonus | o | NR | o | + | o | NR | o |
| Babinski sign | + | NR | o | + | o | o | o |
| Other | Died at age 4 years, large ventricles at autopsy | Gaunt face, high narrow nasal bridge, short philtrum, everted lower lip, scoliosis, increased tone | Recurrent hypothermia, scoliosis | Unsteady, R hemiparesis | Unsteady | ||
+, finding present; o, finding not present; NR, unknown or observation not recorded.
a
A non-carrier female in K8310 also has frontal hair upsweep.