Craniosynostosis, agenesis of the corpus callosum, serve mental retardation, distinctive facies, camptodactyly, and hypogonadism

Lin-Gettig syndrome: Craniosynostosis expands the spectrum of the KAT6B related disorders

We report two patients with sagittal craniosynostosis, hypoplastic male genitalia, agenesis of the corpus callosum, thyroid abnormalities, and dysmorphic features which include short palpebral fissures and retrognathia. The clinical presentation of both patients was initially thought to be suggestive of Lin-Gettig syndrome (LGS), a multiple malformation syndrome associated with craniosynostosis that was initially reported in two brothers in 1990, with a third patient reported in 2003. Our first patient was subsequently found through exome sequencing to have a de novo mutation in KAT6B, c.4572dupT, p.(Thr1525Tyrfs*16). The second patient was ascertained as possible LGS, but KAT6B mutation testing was pursued clinically after the identification of the KAT6B mutation in Patient 1, and identified a de novo mutation, c.4205_4206delCT, p.(Ser1402Cysfs*5). The phenotypic spectrum of KAT6B mutations has been expanding since identification of KAT6B mutations in genitopatellar syndrome (GPS) and Say Barber Biesecker Young Simpson (SBBYS) syndrome patients. We show that craniosynostosis, which has not been previously reported in association with KAT6B mutations, may be part of the genitopatellar/Say Barber Biesecker Young Simpson spectrum. These two patients also further demonstrate the overlapping phenotypes of genitopatellar and SBBYS syndromes recently observed by others. Furthermore, we propose that it is possible that one or more of the previous cases of LGS may have also been due to mutation in KAT6B, and that LGS may actually be a variant within the KAT6B spectrum and not a distinct clinical entity.

Amyoplasia involving only the upper limbs or only involving the lower limbs with review of the relevant differential diagnoses

Of individuals with Amyoplasia, 16.8% (94/560) involve only the upper limbs (Upper Limb Amyoplasia-ULA) and 15.2% (85/560) involve only the lower limbs (Lower Limb Amyoplasia-LLA). The accompanying paper deals with other forms of Amyoplasia [Hall et al., 2013] and discusses etiology. An excess of one of monozygotic (MZ) twins is seen in both groups (ULA 4/94 (4.3%), LLA 5/85 (5.9%)), gastrointestinal (GI) abnormalities thought to be of vascular origin (bowel atresia and gastroschisis) (ULA 16/94 (17%), LLA 4/85 (4.7%)), small or partial absence of digits (ULA 6/94 (6.2%), LLA 8/85 (9.4%)), and umbilical cord wrapping around the limbs at birth (ULA 3/94 (3.2%), LLA 7/85 (8.2%)) (severe enough to leave a permanent groove). Pregnancy complications occurred in 42/60 (70%) of ULA and 36/54 (67%) of LLA. Prenatal diagnosis, after ultrasound usage became routine, occurred in only 7/25 (28%) of ULA and 5/12 (12%) of LLA. This series may represent an over estimate of the complications and associations occurring in ULA and LLA. Differential diagnoses separating LLA from the genetic forms of "lower limb only" arthrogryposis and ULA from "upper limb only" genetic forms of arthrogryposis and Erb's palsy is provided.

Syndromes and Disorders Associated with Omphalocele (III): Single Gene Disorders, Neural Tube Defects, Diaphragmatic Defects and Others

Omphalocele can be associated with single gene disorders, neural tube defects, diaphragmatic defects, fetal valproate syndrome, and syndromes of unknown etiology. This article provides a comprehensive review of omphalocele-related disorders: otopalatodigital syndrome type II; Melnick-Needles syndrome; Rieger syndrome; neural tube defects; Meckel syndrome; Shprintzen-Goldberg omphalocele syndrome; lethal omphalocele-cleft palate syndrome; cerebro-costo-mandibular syndrome; fetal valproate syndrome; Marshall-Smith syndrome; fibrochondrogenesis; hydrolethalus syndrome; Fryns syndrome; omphalocele, diaphragmatic defects, radial anomalies and various internal malformations; diaphragmatic defects, limb deficiencies and ossification defects of skull; Donnai-Barrow syndrome; CHARGE syndrome; Goltz syndrome; Carpenter syndrome; Toriello-Carey syndrome; familial omphalocele; Cornelia de Lange syndrome; C syndrome; Elejalde syndrome; Malpuech syndrome; cervical ribs, Sprengel anomaly, anal atresia and urethral obstruction; hydrocephalus with associated malformations; Kennerknecht syndrome; lymphedema, atrial septal defect and facial changes; and craniosynostosismental retardation syndrome of Lin and Gettig. Perinatal identification of omphalocele should alert one to the possibility of omphalocele-related disorders and familial inheritance and prompt a thorough genetic counseling for these disorders.

Testing causal mechanisms of nonsyndromic craniosynostosis using path analysis of cranial contents in rabbits with uncorrected craniosynostosis

OBJECTIVE

Various causal mechanisms of familial nonsyndromic craniosynostosis have been presented. One hypothesis suggests that overproduction of bone at the suture is the primary origin of craniosynostosis, which affects brain and cranial growth secondarily through altered intracranial pressure (Primary Suture Fusion Model). Other hypotheses suggest that decreased cranial base growth or abnormal brain growth are the primary cause of craniosynostosis (Cranial Base, Brain Parenchyma Models, respectively). This study was designed to investigate which model best describes neurocranial changes associated with craniosynostosis in a rabbit model through multivariate path analysis.

DESIGN

Serial magnetic resonance imaging scans and intracranial pressure measurements were obtained at 10, 25, and 42 days of age from 18 rabbits: six controls, six with delayed-onset synostosis, and six with early-onset synostosis. Five variables were collected from each rabbit: calvarial thickness at the affected suture, cranial base length, brain volume, cerebrospinal fluid volume, and intracranial pressure. This data set was used to test causal pathway relationships generated by the proposed models. Goodness of fit was measured by experimental group for each model.

RESULTS

Primary Suture Fusion Model best explained the variables in both delayed-onset and early-onset synostotic rabbits (Goodness of fit = 93%, 97%, respectively). Cranial Base Model (Goodness of fit = 94%) best explained the data in control rabbits.

CONCLUSION

Results suggest that the primary site of craniosynostosis in craniosynostotic rabbits is most likely the synostosed suture. Other cranial vault anomalies are most likely secondary compensatory changes. Results of the present study may provide insight regarding the causal pathway of craniosynostosis.

Possible third case of Lin-Gettig syndrome

We report a patient with craniosynostosis, severe mental retardation, absence of the corpus callosum, camptodactyly, hypogonadism, and ventricular septal defect. We propose that he has Lin-Gettig syndrome and that he is the third reported patient with this entity. Our patient also had additional phenotypic features, including palatal cleft and absent rapid eye movement (REM) sleep that were not present in the two previously described patients with this syndrome. High-resolution karyotype and subtelomeric fluorescence in situ hybridization (FISH) for cryptic telomeric rearrangement were normal. The existence of an unrelated patient with Lin-Gettig syndrome supports that this is a separate and distinct clinical entity.

Semilobar holoprosencephaly, coronal craniosynostosis, and multiple congenital anomalies: a severe expression of the Genoa syndrome or a newly recognized syndrome?

We report on a female newborn with holoprosencephaly, craniosynostosis, and multiple congenital anomalies including cloverleaf skull, Dandy-Walker malformation, bilateral microphthalmia, cleft soft palate, congenital scoliosis, hypoplastic nails and coarctation of aorta. Some of these features are consistent with the diagnosis of the Genoa syndrome, (MIM 601370) a rare autosomal recessive disorder recently described. The findings of other serious and previously undescribed malformations, however, raises the possibility of a newly recognized disorder.

Omphalocele in Miller-Dieker syndrome: expanding the phenotype

We report on a patient prenatally diagnosed with omphalocele, mild cerebral ventriculomegaly, nuchal fold thickening, and cystic changes in the umbilical cord who was found postnatally to have lissencephaly type I. Prenatal chromosome analysis showed a normal male karyotype; however, postnatal high resolution banding and FISH analysis, using a probe for locus D17S379 in chromosome region 17p13.3, demonstrated a deletion at 17p13.3 consistent with Miller-Dieker syndrome (MDS). A review documented four more cases with MDS/isolated lissencephaly/17p-, with omphalocele. Because MDS is a contiguous gene disorder, we speculate that a gene or genes in this region have a major role in the closure of the lateral folds or the return of the midgut from the body stalk to the abdomen at 5-11 weeks of gestation. Prenatal diagnosis of omphalocele with mild ventriculomegaly should prompt FISH analysis for a deletion in 17p13.3.

Delineation of the da-Silva syndrome

We present a 6-month-old boy with agenesis of the corpus callosum, hypertonicity, severe growth and psychomotor retardation, microcephaly, large prominent ears, and delayed bone age. Similarity of his manifestations to these in 3 sibs described by da-Silva in 1988 suggests initial delineation of the da-Silva syndrome.

Cerebral malformation, seizures, hypertrichosis, distinct face, claw hands, and overlapping fingers in sibs of both sexes

We report on sibs of both sexes with a multiple malformation syndrome of cerebral malformation, seizures, hypertrichosis, distinct face, claw hands, and overlapping fingers. The older boy died in a tonic extension spasm at age 4 months. When discharged, the younger girl was 3.5 months old. This appears to be an autosomal recessive syndrome which to our knowledge has not been described before.

New case of Toriello-Carey syndrome

A new syndrome was identified by Toriello and Carey (Am J Med Genet 31:17-23, 1988), based on the description of four children, three of whom were sibs. The main manifestations included agenesis of the corpus callosum, telecanthus, short palpebral fissures, small nose with anteverted nares, retrognathia, abnormal ears, laryngeal and cardiac anomalies, brachydactyly, and hypotonia. We describe findings in a patient, presumed to be another case of the Toriello-Carey syndrome, which extend the phenotype of the syndrome.