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schinzel  giedion midface retraction syndrome ( sgs ; mim%269150 ) is a recognizable malformation syndrome characterized by severe psychomotor retardation , seizures , distinctive facial features , and multiple congenital anomalies in the cardiac , genitourinary , renal , skeletal , and central nervous systems .
the highly characteristic facial appearance consists of high , prominent forehead , low nasal root , ocular hypertelorism , midface hypoplasia , and lowset ears 5 , 7 , 10 .
a higher risk of embryonal tumors , particularly malignant sacrococcygeal teratoma , has been noted in patients with this syndrome in comparison with the normal population 8 .
the prognosis of patients with sgs is poor , and most patients die during early childhood .
the disease phenotype occurs sporadically in most cases , suggesting the involvement of an autosomal dominant mutation in a single gene 1 .
hoischen et al . 2 recently sequenced the exomes of four unrelated patients with sgs and found heterozygous de novo mutations in setbp1 .
the father was 34 years old and the mother 30 years old when he was born .
two older sisters , 14 and 7 years old , and a 6yearold brother were phenotypically normal . at 29 weeks of gestation ,
the male infant was delivered at 39 weeks and 1 day of gestation , weighing 3185 g and with a length of 48 cm .
serial apneic attacks were noted during early infancy , and he developed infantile spasms by 1 year old .
abnormalities were identified on electroencephalography , and antiepileptic agents were administered . at 14month old , he was referred to tenshi hospital for surgical treatment of a tumor developing in the sacrococcygeal region . at that time , serious psychomotor retardation was evident .
distinctive dysmorphic features were evident , including prominent forehead , hypertelorism , shallow orbits , thick eyebrows , long eyelashes , depressed nasal root , upturned nostrils , lowset ears , hypospadias , right undescended testis , and overlapping fingers .
further examinations revealed atrophy of bilateral optic nerves , bilateral sensorineural deafness , broad ribs , and bilateral hydronephrosis ( fig .
the tumor was removed surgically at 16month old , and histological analysis revealed malignant teratoma .
dna was extracted from peripheral lymphocytes , and the setbp1 coding sequence was determined according to standard protocols .
a heterozygous guaninetoadenine missense mutation was found at position 2602 , predicting an amino acid substitution ( d868n ) .
the patient died at 2 years and 9 months old due to generalized metastasis of malignant teratoma .
general appearance just after birth ( a ) , facies ( b ) , overlapping fingers ( c ) , tumor in the sacrococcygeal region ( d ) , and bilateral hydronephrosis ( e ) . color figure can be viewed in the online issue , which is available at http://onlinelibrary.wiley.com/journal/10.1002/(issn)1552-4833 .
the father was 25 years old and the mother 24 years old when she was born . at 28 weeks of gestation
, the mother was sent to our hospital after esophageal atresia was suspected in the fetus .
excess amniotic fluid , hydrocephalus , bilateral hydronephrosis , overlapping fingers and toes , high prominent forehead , hypertelorism , and depressed nasal root were observed in the fetus on ultrasonography ( fig .
the female infant was delivered at 37 weeks and 4 days of gestation , weighing 3106 g and with a length of 47 cm .
soon after birth , she developed respiratory difficulty due to middle airway obstruction attributed to the posteriorly placed tongue and narrow nasal cavity .
the patient showed a characteristic facial appearance with high prominent forehead , hypertelorism , upturned nostrils , midface hypoplasia , depressed nasal root , and micrognathia ( fig .
she also had a large fontanel , malformed auricles , lowset ears , and overlapping fingers and toes ( fig .
setbp1 coding sequence analysis revealed a heterozygous guaninetoadenine missense mutation at position 2608 , predicting amino acid substitution ( g870s ) .
ultrasonography at 30 weeks of gestation ( a  c ) and postnatal images ( d  f ) . facial appearance ( a , d ) , overlapping toes ( b , e ) , and bilateral hydronephrosis ( c , f ) .
color figure can be viewed in the online issue , which is available at http://onlinelibrary.wiley.com/journal/10.1002/(issn)1552-4833 .
this research was prospectively reviewed and approved by the committee for genetic testing and counseling at tenshi hospital in japan .
among the 17 individuals with sgs tested with setbp1 sequencing to date , 16 have shown heterozygous mutations in a highly conserved 11bp exonic region 2 , 3 , 6 , 12 .
these mutations predicted substitutions at amino acid 868 in five patients , amino acid 870 in five , and amino acid 871 in six .
the mutations identified in our patients , namely d868n and g870s , were both recurrent 2 , 12 .
prior to delivery , polyhydramnios was noted with patient 1 . among nine sgs patients for whom prenatal findings
were reported , polyhydramnios was observed in two and fetal hydronephrosis in six 3 , 4 , 6 , 7 , 9 , 11 , 13 .
polyhydramnios is caused by excess production of amniotic fluid or poor swallowing of amniotic fluid by the fetus .
obstructive disorders of the upper digestive tract such as esophageal atresia and duodenal atresia may cause polyhydramnios , as might neuromuscular disorders that cause impaired swallowing of amniotic fluid . after birth , hydronephrosis
prenatal ultrasonography thus predicted hydronephrosis in six of the nine fetuses for which findings have been reported .
13 reported that many sgs patients displayed several types of urinary tract anomalies , such as pyeloureteral junction stenosis , ureterovesical junction stenosis , and vesicoureteral reflux .
interestingly , two patients were recorded as having polyhydramnios along with hydronephrosis on prenatal ultrasonography 3 , 11 . in those fetuses , urine volume
should theoretically have been reduced , but other mechanisms such as impaired swallowing function might have resulted in increased amounts of amniotic fluid .
a combination of polyhydramnios , overlapping fingers , hydrocephalus , and hydronephrosis on prenatal ultrasonography may represent strong evidence for the prenatal diagnosis of sgs and other malformation syndromes including trisomy 18 . in patient 2 in this report , findings from prenatal ultrasonography matched those found in typical sgs infants . in particular , the facial appearance on threedimensional ultrasonography was typical of sgs and differed from that of trisomy 18 ( fig .
when polyhydramnios is observed , additional fetal findings such as overlapping fingers , hydrocephalus , hydronephrosis , and a typical facial appearance with high , prominent forehead , hypertelorism , and depressed nasal root may suggest sgs .
prenatal diagnosis of sgs is noteworthy in providing advance notice of serious clinical problems in the neonatal period and allowing planning for appropriate management of the affected infant .
key clinical messagewe report two japanese patients with schinzel  giedion syndrome . when polyhydramnios is observed , additional fetal findings such as overlapping fingers , hydrocephalus , hydronephrosis , and very characteristic facial appearance comprising high , prominent forehead , hypertelorism , and depressed nasal root may suggest schinzel  giedion syndrome .