Fig. 1.

Three families carrying homozygous GTPBP2 (NM_019096.4) non-sense variants. Stars denote individuals analysed by WES. Allelic status for the variants in question is provided below individual symbols in the pedigrees. Sequence traces confirming the primary WES data are shown to the right; the predicted consequences at protein are indicated below the traces. a Family 1 and variant c.1219C>T. b Family 2 and variant c.1408C>T. Several third and fourth-degree relatives of the index case are affected by a reportedly similar disease (grey symbols). Dotted relationship lines indicate that consanguinity is likely. c Family 3 and variant c.430C>T. d Magnet resonance imaging of the index patient III-3 from family 1 at age 6 years. On the left: sagittal T1-weighted spin-echo image discloses a thin corpus callosum (arrowhead) with absent rostrum (arrow), hypoplasia of cerebellar vermis (stippled arrow) and presence of mega cisterna magna (star). On the right: axial T2*-weighted fast field-echo image (section through upper tectum) does not reveal evidence for specific hypointensities in the globus pallidus bilaterally (arrows) or in the substantia nigra (arrow heads). e Index patient from family 3 at age 2 years. Note dysmorphic features and sparse hair