Okamoto Syndrome


Okamoto syndrome is characterised by congenital hydronephrosis, intellectual deficit, growth retardation, cleft palate, generalised hypotonia and a characteristic face. Cardiac anomalies have also been reported. To date, 6 cases have been reported.


Okamoto et al. (1997) reported what they believed to be a new MCA/MR syndrome in a 2-year-old Japanese girl and an unrelated 15-month-old Japanese boy. Manifestations included congenital hydronephrosis, severe mental retardation, growth failure, generalized floppiness, and cleft palate. The facies showed midface hypoplasia, hypertrichosis, long eyelashes, prominent eyes, epicanthus, low-set ears, long ear lobe, flat nasal bridge, short upturned nose, long philtrum, and webbed neck. The girl had mild aortic stenosis and regurgitation; ventricular septal defect, atrial septal defect, and patent ductus arteriosus (see 607411) had closed. The boy had endocardial cushion defect. In both patients, the karyotype was normal, the parents were nonconsanguineous and healthy, and sibs were normal.

Wallerstein et al. (2005) reported a 6-month-old Chinese American boy with congenital hydronephrosis, cleft palate, severe hypotonia, congenital heart defect, developmental delay, and characteristic facial features with an open-mouthed appearance and full lower lip. The authors considered this to be the third reported case of Okamoto syndrome. The infant also had idiopathic splenomegaly and nonspecific MRI changes in the brain, which had not been reported in the first 2 cases.

Markouri et al. (2008) reported a 2-year-old Greek female with Okamoto syndrome, born to healthy, nonconsanguineous parents. The child had multiple congenital anomalies including cleft palate, stenosis of the ureteropelvic junction with hydronephrosis, and cardiac anomalies, along with generalized hypotonia, severe developmental delay, and growth failure. The distinctive facial appearance included microcephaly, midface hypoplasia, prominent eyes, epicanthal folds, long eyelashes, synophrys, low-set ears with long earlobe, flat nasal bridge with short upturned nose, open mouth appearance, full lower lip, and downturned mouth. Unlike previously reported patients, she had severe anal stenosis.

Taylor and Aftimos (2010) reported what they believed to be the fifth reported case of Okamoto syndrome. The female offspring of nonconsanguineous parents of mixed ethnic background had multiple congenital anomalies and characteristic facial features. Echocardiogram showed severe aortic stenosis with mildly hypoplastic left ventricle, mild mitral valve hypoplasia, and 2 small atrial septal defects. She was profoundly hypotonic and made little spontaneous movement. In the facies, she had mild supraorbital ridging and hypertrichosis of the forehead, temple, and cheeks, prominent eyes with large palpebral fissures and hypertelorism, depressed nasal bridge and infraorbital grooves, short upturned nose, tented upper lip, cleft palate, large and low-set ears, and redundancy of skin of the posterior neck. A brain MRI showed thinning of the corpus callosum and presence of germinolytic cysts within the lateral ventricles. She also had intestinal malrotation and uterine didelphyis, features not reported previously. She died at age 12 days after the withdrawal of supportive medical care.