Table 2.

Primary Comorbidities and Clinical Features of CM1 Patients

	N, % of Sample	Avg. age at CM1 diagnosis (yrs)	Avg. tonsillar ectopia (mm)	Avg. Obex descent (mm)	% with syrinx	% receiving PFD
Central Nervous System	113 (18%)	7.9	9.3	+2.58	26	30
Epilepsy	19	6.2	10.1	+2.92	22	17.6
Hydrocephalus	17	2.3	10.4	−0.09	29	35.3
Autism/Developmental Delay	14	9	10.1	+3.11	0	20
Growth Hormone/Pituitary Issues	13	7.7	10.1	+3.42	18	54.5
Arachnoid/Cerebral Cysts	12	10.5	8.0	+3.31	18	9.1
Ventriculomegaly	7	2	7.0	+5.95	40	14.2
Tethered Cord/Spinal Anomaly	7	5	7.7	+3.90	43	57
Pseudotumor Cerebri	5	16	9.1	−0.45	20	20
Macrocephaly	5	1.2	10.2	+3.10	20	25
Cerebral Palsy	4	5	7.5	−2.40	0	75
Cortical Malformations	4	7	5.0	+0.65	0	0
White Matter Abnormality	4	9.5	11.5	+1.05	0	50
Stroke/Intraventricular hemorrhage	2	1.5	8.5	+9.65	0	50
Skeletal	47 (8%)	6.8	10.1	+1.06	30	47
Hypermobility/Joint Laxity	15	8.6	9.3	+3.48	40	26.6
Craniosynostosis	8	5	8.5	+3.56	25	50
Platybasia	7	8.4	15.3	−0.76	14	57.1
Other Bone Malformations	5	3	8.8	−3.60	20	40
Congenital Scoliosis	3	15.3	7.3	−2.23	0	67
Congenital Torticollis	2	11	22.5	unknown	0	0
Pyriform Aperture Stenosis	2	5	9.0	−3.65	0	50
Hemivertebrae	2	3	11.0	−4.45	50	50
Vitamin D Rickets	1	13	13.0	+1.4	0	0
Spinal Trauma	1	8	17.0	unknown	0	0
Multiple Congenital Anomalies (MCA)	26 (4%)
Varied	26	5.6	12.3	+5.02	27	42
Idiopathic	427 (70%)
Varied	427	10.3	10.0	+2.19	26	37
Overall Sample	612 (100%)	9.4	10.0	+2.30	25	38