Table 1 Comparison of the clinical phenotype of patients with SMG9 mutation reported by other groups
Patients clinical data | Our patient | Altuwaijri et al. [12] | Lemire et al. [11] | Shaheen et al. [9] | Lecoquierre et al. [10] | Rahikkala et al. ([13], 5 patients) | ||||
|---|---|---|---|---|---|---|---|---|---|---|
Proband | Affected sister | Patient 1 | Patient 2 | Family I | Family II-proband | Family II-proband's first cousin | ||||
Variants in SMG9 (NM_019108.3) | c.947A>G (p.His316Arg) and c.1318_1319delAG (p.Ser440*) | c.701+4A>G (p.Tyr197Aspfs*10) | c.1508G>C (p.Trp503Ser) | c.520_521delCC (p.Pro174Argfs*12) | c.701+4A>G (p.Tyr197Aspfs*10) | c.1177C>T (p.Gln393*) | c.551T>C (p.Val184Ala) | |||
Gender | Male | Female | Male | Female | Female | Female | Female | Female | Female | Male |
Age at last examination | 5 year | 10 years | Died at 25 months | Died at 1 h after birth | 7 years | Died at 7 weeks | Died at 7 weeks | 8 years | 5 years | ≥ 25 years in all the 5 patients |
Neurodevelopment | Severe ID | Severe ID | Global developmental delay | NA | Severe ID | NA | Global developmental delay | Global developmental delay | Severe psychomotor developmental delay | 1/5 mild ID, 3/5 moderate ID, 1/5 borderline mild/moderate ID |
Height, weight, head circumference | 110.3 cm (50%, 0.0 SD), 20.2 kg (+ 0.4SD), 50 cm (− 0.5SD) | 132.1 cm (10%, − 1.1SD), 31.2 kg (49.5%, 0.0SD) | 74 cm (< 1%, − 3.7SD), 8.9 kg (< 1%, − 3.1SD), 44 cm (< 1%, − 3.2SD) | NA | 118.5 cm (30%), 25.1 kg (75%), 49.5 cm (25%) | 44 cm (− 2.4SD), 2.130 kg (5%), 31.5 cm (− 2.2SD) | 47 cm (15%, − 2.2SD), 2.26 kg, 32 cm (− 1.8SD) | 69 cm (− 4.8SD), 6.3 kg (− 5.2SD), 39 cm (− 6SD) | All three metrics were less than 3SD at the age of 2.5 years | 3/5 short stature, 2/5 microcephaly |
Age of walking | 31 months but continues to exhibit an unsteady gait | 35 months but continues to exhibit an unsteady gait | NA | NA | 7 years but walk with a walker and ankle foot orthosis | NA | NA | Unstable to sit alone | Inability to walk | ≤ 20 month |
Development of speech and language skills | No meaningful language | Nonverbal | NA | NA | Nonverbal | NA | NA | Nonverbal | Nonverbal | Markedly delayed |
Behavioral anomalies | Recurrent stereotypical body rocking, hand flapping and spinning | Recurrent hand flapping | Â | NA | Recurrent hand flapping and stereotypical body rocking | Â | Â | Â | Â | Â |
Brain radiologic features | Mild generalized brain atrophy hypomyelination, and small globus pallidus and putamen | Not performed | Brain atrophy, abnormally shaped lateral ventricles, thin corpus callosum, cerebellar and pontine atrophy with flattening of the pons ventral aspect, diffuse | Not performed | Normal | Dandy–Walker malformation | Brain atrophy, decreased myelination, and Dandy–Walker malformation | Generalized brain atrophy, prominent ventricular system and thin corpus callosum | Enlarged fourth ventricle with dysmorphism, a parieto-occipital junctional stroke, thin corpus callosum, a cavum septum pellucidum, and a Blake's pouch cyst | 1/5 abnormal 2/5 normal |
Feeding difficulty | Yes | Yes | Yes | NA | Yes | Â | Â | Â | Yes | Yes |
Muscular hypotonia | Yes | Yes | Yes | NA | Yes | NA | Yes | Yes | Yes | 2/5 abnormal |
Ocular anomalies | Duane syndrome | Poor vision | Bilateral sutural cataract | NA | Bilateral Duane syndrome type III, high hyperopia, and astigmatism | Microphthalmia | Microphthalmia | Â | Hypertelorism, ptosis, and bilateral cataracts | 4/5 abnormal |
Cardiovascular | Atrial septal defect and VSD | VSD, hypoplastic tricuspid valve | Interrupted inferior vena cava, a small ASD with left to right shunt | Ectopia cordis | ASD and a large perimembranous VSD | Interrupted aortic arch, hypoplastic tricuspid and aortic valves, large muscular VSD | Large VSD | VSD | VSD, aortic valve bicuspidy and aortic dilatation | 1/5 abnormal 4/5 normal |
Infections | No | No | Yes | NA | Yes | Yes | Â | Â | Yes | Yes |
Facial dysmorphic fetaures | Broad nasal bridge, low set malformed ears and left-sided ptosis, prominent forehead | Broad nasal bridge, low set malformed ears, prominent forehead | Microretrognathia, anteverted nares, and hypertelorism, unilateral ear malformation and bilateral external auditory canal stenosis | NA | Long and oval face, narrow mouth, bifrontal narrowing with frontal bossing, prominent nose with bulbous tip, and high anterior hairline | Prominent forehead and occiput, low set malformed ears, wide anterior fontanelle, depressed nasal bridge and anteverted nares, high arched palate | Narrow forehead, prominent metopic suture, posteriorly rotated ears with attached lobules, hypertelorism, small eyes, broad nasal bridge, full and everted lower lip, right-sided cleft lip | Dysmorphic features | Left cleft lip and palate, transient frontal white hair lock, bi-temporal retraction with frontal bossing, upslanting palpebral fissures with hypertelorism, broad nasal bridge, midface hypoplasia, low-set posteriorly rotated ears with attached lobules, Widow's peak | Abnormal |