Table 1.

Phenotypic Findings

Phenotypic Findings	Affected/Total (%)
Neonatal
Polyhydramnios	19/45 (42.2)
Neonatal Feeding Issues	41/50 (82.0)
Infantile Hypotonia	50/50 (100)
Neurology
Intellectual Disability/DD	50/50 (100)
Macrocephaly-Birth	26/43 (60.4)
Macrocephaly-Current	45/49 (91.8)
Seizures/Epilepsy	12/50 (24)
Abnormal MRI	27/45 (60)
Non-Verbal (<4 years)	5/15 (33.3)*
Non-Verbal (>4 years)	7/35 (20)*
Non-Ambulatory (<3 years)	3/9 (33.3)*
Non-Ambulatory (>3 years)	2/41 (4.9)*
Wide-based Gait	41/45 (91.1)
Orthotics	25/41 (61.0)
Deafness	1/50 (2)
Behavioral
Good Eye Contact	49/50 (98)
Social Reciprocity	49/50 (98)
Not Toilet Trained (<4 years)	15/15 (100)
Not Toilet Trained (>4 years)	22/35 (62.9)
Cardiac
Bicuspid Aortic Valve	5/50 (10)
Cardiac intervention	2/50 (4)
Ophthalmologic
Strabismus	44/50 (88)
Anisocoria	7/46 (13.6)
Astigmatism	19/46 (41.3)
Hyperopia	14/46 (30.4)
Myopia	10/46 (21.7)
Optic Nerve Hypoplasia	4/44 (9.1)
Deafness	1/50 (2.0)
Dysmorphology
Prominent Forehead	37/37 (100)
Hypertelorism	29/37 (78.4)
Prominent/Bulbous Nasal Tip	31/37 (83.8)
Pointed Chin	34/37 (91.9)

^*specific ages of non-verbal and non-ambulatory subjects are noted in Table S4.