Table I. Clinical and Molecular Findings of the Seven Evaluated Patients.

	Family 1		Family 2	Family 3	Family 4	Family 5	Family 6
	Patient 1	Patient 2	Patient 3	Patient 4	Patient 5	Patient 6	Patient 7
Phenotype	MMIHS	MMIHS	MMIHS	MMIHS	MMIHS	CIPO	MSMDS
Parental	+	+	−	−	−	−	−
consanguinity
Familial	+ (Patient 2)	+ (Patient 1)	−	−	−	−	−
recurrence
Pathogenic
variant
ACTG2*	NE	Not identified	C.532c>T (p.Argl78Cys) Het—de novo	c770G>A (p.Arg257His) Het—de novo	.533G>T (p.Arg178Leu) Het—de novo	c.584C>T (p.Thr195lle) Het— unknown origin	Not identified
ACTA2*	NE	Not identified	NE	NE	NE	NE	c. 535c>T (p.Arg179Cys) Het—unknown origin
MYH11**	NE	Not identified	NE	NE	NE	NE	NE
Gender	M	F	M	F	M	F	F
Newborn data	Live	Live	Live	Live	Live	Live	Live
vitality
Weight [g] (centile)	1,935 (<p10)	4,150 (>90)	2,600 (10–25)	3,360 (50–75)	3,025 (75–90)	3,320 (50–75)	3,690 (75–90)
Length [cm] (centile)	38 (<p10)	50 (50–75)	42 (10)	50 (25–50)	49 (75–90)	NS	48 (10–25)
OFC [cm] (centile]	31 (p10)	34.5 (50–75)	32 (25)	36 (90)	33 (50–75)	NS	35 (75)
Gestational age [weeks]	36	38	36	39	35	37	38
Apgar score	3/8	9/10	7/10	9/10	8/9	NE	8/9/9
Age	Death (1 mo)	Death (1 y 8 mo)	Death (7 mo)	Death (11 mo)	5 mo	5y	2 y 10 mo
Paternal age (years)a	21	23	30	38	32	34	38
Maternal age (years)a	24	2B	29	34	25	27	29
Prenatal findings	Hydronephrosis, megacystis, oligohydramnios	Hydronephrosis, megacystis, polyhydramnios	Hyperechogenic kidneys, hydroureter, megacystis, club feet	Megacystis, polyhydramnios	Megacystis	Megacystis	Hydronephrosis, hydroureter, megacystis
Fetal bladder diversion	Vesicoamniotic shunt	−	−	−	−	−	−
Megacystis	+	+	+	+	+	Episodic	+
Prune-belly	+	+	+	−	−	−	−
phenotype
Microcolon	+	+	+	−	+	−	−
Intestinal hypoperistalsis	+	+	+	+	+	+	+
Mydriasis	NE	+	−	−	−	−	+
Parenteral  lnutrition  dependence	+ (Total)	+ (Total)	+ (Total)	+ (Total after 4 mo)	+ (Total)	+ (Intermittent)	+ (Intermittent)
Bladder catheterization and/or vesicostomy	+	+	+	+	+	−	+
Other findings	Hydronephrosis, sparse renal cyst, renal failure, dilated stomach, intestinal malrotation, hypoplastic terminal ileum	Hydronephrosis, intestinal malrotation, hypoplastic small intestine	Hydronephrosis, renal cysts, hydroureter, stomach dilatation		Cerebral ventriculomegaly, temporal epileptiform discharges	Stomach and large intestine dilatation	Hydronephrosis, hydroureter, intestinal malrotation, ASD, ductus arteriosus aneurysm, pulmonary valve dilatation, cerebrovascular abnormalities
Histologic findings	Renal dysplasia, chronic pyelonephritis, acute tubular necrosis, intrahepatic cholestasis	Vacuolization of muscularis propria layer (bladder and small intestine)	NE	Normal (stomach, small and large intestine)	Enterocolitis	Vacuolization and fibrosis of muscularis propria layer (stomach, gallbladder, small and large intestine)	Normal (large intestine)
Surgery	Exploratory laparotomy, gastrostomy, ileostomy, vesicostomy, appendicectomy	Gastrostomy, ileostomy, vesicostomy, multivisceral transplantation	Ileostomy, vesicostomy	Gastrostomy, ileostomy	Ileostomy	Ileostomy, partial gastrectomy with Roux loop anatomosis, cholecystectomy, exploratory laparotomy, right hemicolectomy	Ligation of ductus arteriosus, gastrostomy, sigmoid resection
Follow up	Deceased	Deceased	Deceased	Deceased	Supportive treatment	Episodic intestinal pseudo-obstruction, supportive treatment	Supportive treatment

^aparental age in years at the birth of the patient; ASD, atrial septal defect; CIPO, chronic intestinal pseudo-obstruction; F, female; Het, heterozygous; M, male; MMIHS, megacystis-microcolon-intestinal hypoperistalsis; mo, months old; MSMDS, i smooth muscle dysfunction syndrome; NE, not evaluated; OFC, occipital frontal circumference; y, years old; +, feature present; —, feature absent.

^*Evaluated by Sanger sequencing in patients 2-7 (both genes were also tested by whole-exome sequencing in patient 2).

^**Evaluated by whole-exome sequencing in patient 2.