Table 1.

Phenotypic features of the patients

Patient No (Pedigree No, Figure 1)	Patient 1 ( IV.1)	Family 1	Patient 3 (IV.4)	Patient 4 (IV.5)	Family 2	Patient 6 (IV.11)
		Patient 2 (IV.3)			Patient 5 (IV.6)
Sex	F	M	F	M	M	F
Gestational age	Term	Term	Term	Term	Term	Term
Excessive fetal movement	+	+	+	NA	+	+
Birth weight (gm)	2985	3200	2620	NA	2980	2970
Occipitofrontal circumference (cm)	30.5	32	31	NA	31	31
Signs of hyperekplexia
• Stiffness	+	+	+	+	+	+
• Non-habituating generalized flexor spasm to glabellar tap	+	+	+	+	+	+
• Exaggerated persistant Startle reaction to stimuli	+	+	+	+	+	+
Major neurologic findings
• Microcephaly	+	+	+	+	+	+
• Hypertonia	+	+	+	NA	+	+
• Arthrogryposis	+	+	+	NA	+	+
Ophthalmic examination	Bilateral optic atrophy	Bilateral optic atrophy	Bilateral optic atrophy	NA	Bilateral optic atrophy	Bilateral optic atrophy
Electroencephalography (EEG)	• Background: Widespread low voltage brain waves, with occasional synchronized jerks mostly myogenic in origin.	• Background: Consisted of low voltage brain wave tracing all over the record.	NA	NA	• Background: Diffuse slow activity with low voltage for age.	EEG: Full of motion artifacts but the background was continuous without epileptic discharges.
		• Prominent electrical contamination from the ventilator.			• No spikes or sharp waves and no abnormal focal changes.
		• Occasional synchronized jerks most likely coming from the muscle.			• No electrical sign of seizure activity.
Metabolic screen	Negative	Negative	Negative	NA	Negative	Negative
Chromosome analysis	46XX	46XY	46XX	NA	46XY	46XX
CT brain	Figure 2A & B: Brain underdevelopment with large extra cerebral CSF spaces	Figure 2C: Remarkable brain under-development with very few sulci in frontal and temporal lobes. Sylvian fissures are under-developed and wide open.	Figure 2E & F: Remarkable cerebral and cerebellar under-development, simplified gyral pattern and enlargement of extra cerebral CSF spaces.	NA	Cerebral and cerebellar atrophy	NA
MRI brain	NA	Figure 2 D: Small cerebellar vermis.	NA	NA	NA	Figure 2 G & H: Simplified gyral pattern. The frontal and temporal lobes are very few and shallow. Sylvian fissures are wide open.
Age at death	6 weeks	2 weeks	6 weeks	4 days	4 weeks	3 weeks

+ = Present, NA = Not available.