]>

Table 2: Patient and mutation data were obtained from the European Skeletal Dysplasia Network (ESDN reference numbers) or recent publications, as referenced.

Reference Features Diagnosis Gene Mutation Effect ESDN 01071 – Fatigue during walking MED MATN3 D176V Potential misfolding – Muscle disease suspected by paediatrician ESDN 01013 – Mild proximal muscle weakness at 7 years MED COL9A2 c186G C Exon skipping – Difficulty rising from squatting position ESDN 01003 – Mild muscle weakness MED COL9A2 c186 + 4a c Exon skipping [68] – Muscle weakness MED COL9A2 c186 2t c Exon skipping – Suspected (unproven) muscular dystrophy – Problems with standing up from sitting position – Problems walking on stairs – Biopsy:  – No morphological or histochemical changes  – No fibers with central nuclei  – Variation in fiber size  – No degradation, regeneration, or necrosis  – ATP CrP production from pyruvate decreased [68] – Neurological evaluation for abnormal walking MED COL9A2 c186G A Exon skipping pattern at 6 years – Proximal muscle weakness lower extremities – Family also affected (father, sister, sister’s daughter) [54] – Proximal muscle weakness (reported to the MED COL9A3 IVS2-1, G A Exon skipping neuromuscular clinic at 10 years) – Mildly elevated serum creatine kinase (CK) levels – Difficulty walking and climbing stairs from 3 years on – Difficulty rising from the floor – Some signs of proximal muscle weakness in family members – Muscle biopsy: mild variability in fibre size ESDN 00385 – Some signs of mild myopathy PSACH COMP D326Y Potential retention (T3 domain mutation)  – Gower's sign (proximal muscle weakness)  – Waddling gait  – Difficulties climbing stairs – CPK normal ESDN 00430 – Reported to neurologist at age 2 MED COMP E457del Potential retention (T3 domain mutation) – Diminished muscle strength in:  – Hips  – Shoulders  – Quadriceps muscle  – Feet-lifting muscles – Diagnosed with a myopathy at 5 years – Biopsy inconclusive [55] – Difficulty walking at 2.5 years MED COMP D605N Potential misfolding (CTD mutation) – Muscle weakness – Tired easily – Difficulty getting up from sitting – CK levels normal – EMG and nerve conduction velocities normal – Biopsy:  – Mild myopathy,  – No variability in fibre size  – Scattered basophilic fibers  – Some small atrophic fibers [53, 55] – Muscle weakness from 3 years on MED COMP R718W Potential misfolding (CTD mutation) – Referred to neuromuscular clinic at 5 years – Mildly elevated CK levels