Coexistence of dyschondrosteosis associated to SHOX deficiency, pseudohypoparathyroidism 1B, and chronic autoimmune thyroiditis: a case report.

We present an unusual case of SHOX deficiency associated with Léri-Weill dyschondrosteosis (LWD), Hashimoto's thyroiditis and pseudohypoparathyroidism 1B in a young woman. To our knowledge, this is the first ever report of these disorders coexisting. At the age of nine years, the proband was diagnosed of hypothyroidism due to Hashimoto's thyroiditis, and developed biochemical abnormalities consistent with hyperphosphatemia, mild hypocalcemia and elevated parathyroid hormone without any clinical symptoms except short stature. Replacement therapy with levothyroxine, calcium and alphacalcidol was initiated. The diagnosis of pseudohypoparathyroidism 1B was confirmed at the age of 17.5 years with the demonstration of methylation alteration at the GNAS locus. At the age of 16 years, 3.5 years after her menarche, she presented clear features of LWD. A large deletion of the SHOX gene was confirmed. Family genetic tests were not doable since she was adopted. We discuss the diagnostic challenges of these coexisting rare endocrinopathies.

Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity.

ABL1 is a proto-oncogene encoding a nonreceptor tyrosine kinase, best known in the somatic BCR-ABL fusion gene associated with chronic myeloid leukaemia. Recently, germline missense variants in ABL1 have been found to cause an autosomal dominant developmental syndrome with congenital heart disease, skeletal malformations and characteristic facies. Here, we describe a series of six new unrelated individuals with heterozygous missense variants in ABL1 (including four novel variants) identified via whole exome sequencing. All the affected individuals in this series recapitulate the phenotype of the ABL1 developmental syndrome and additionally we affirm that hearing impairment is a common feature of the condition. Four of the variants cluster in the myristoyl-binding pocket of ABL1, a region critical for auto-inhibitory regulation of the kinase domain. Bio-informatic analysis of transcript-wide conservation and germline/somatic variation reveals that this pocket region is subject to high missense constraint and evolutionary conservation. Functional work to investigate ABL1 kinase activity in vitro by transient transfection of HEK293T cells with variant ABL1 plasmid constructs revealed increased phosphorylation of ABL1-specific substrates compared to wild-type. The increased tyrosine kinase activity was suppressed by imatinib treatment. This case series of six new patients with germline heterozygous ABL1 missense variants further delineates the phenotypic spectrum of this condition and recognises microcephaly as a common finding. Our analysis supports an ABL1 gain-of-function mechanism due to loss of auto-inhibition, and demonstrates the potential for pharmacological inhibition using imatinib.

A Case of Thumb Polydactyly which Ulnar Thumb Has No Active Motion in Ring Chromosome 4.

The objective of this study was to clarify the difference in thumb deformity between our case with ring chromosome 4 and thumb polydactyly, in which ulnar side was small and had no active motion, and other cases of ring chromosome 4, by analyzing previous reports. Our case had bilateral atypical thumb polydactyly, which was classified as type 4 on the right side and type 5 on the left side, according to the Japanese Society for Surgery of the Hand: Modified International Federation of Societies for Surgery of the Hand classification. Of the 39 cases in previous reports, 20 (51.3%) had thumb deformities. Among them, 19 cases (95%) showed radial ray deficiency and only 1 case (5%) showed bilateral thumb polydactyly. Clinodactyly was seen in 5 cases (12.8%). Foot deformities were present in 6 cases (15.4%). We discussed about thumb polydactyly with and without chromosomal deformities.

ZNF462 and KLF12 are disrupted by a de novo translocation in a patient with syndromic intellectual disability and autism spectrum disorder.

We describe a patient with a de novo balanced translocation 46,XY,t(9; 13)(q31.2; q22.1) and autism spectrum disorder, intellectual disability, a metopic craniosynostosis, a corpus callosum dysgenesis and dysmorphic facial features, most notably ptosis. Breakpoint mapping was performed by means of targeted locus amplification (TLA) and sequencing, because conventional breakpoint mapping by means of fluorescent in situ hybridization and long-range PCR was hampered by a complex submicroscopic rearrangement. The translocation breakpoints directly affected the genes KLF12 (chromosome 13) and ZNF462 (chromosome 9). The latter gene was disrupted by multiple breakpoints, resulting in the loss of three fragments and a rearrangement of the remaining fragments. Therefore, haploinsufficiency of ZNF462 was assumed. Loss-of-function variants in ZNF462 have recently been published by Weiss et al. (2017) in a series of eight patients from six independent families delineating the ZNF462-associated phenotype. The latter closely matches with the clinical features of the current translocation patient. Besides, no direct evidence for an association of KLF12 to the phenotypic features was found. Therefore, we conclude that the phenotype of the current patient is mainly caused by the disruption of ZNF462. We present clinical data from birth to adulthood and data on the cognitive and behavioral profile of the current patient which may add to a more precise counseling and surveillance of development in young children with ZNF462 mutations. In addition, the current case illustrates that TLA is an efficient method for determining complex chromosomal breakpoints.

Prenatal diagnosis of fetal adducted thumbs.

PURPOSE: One of the greatest challenges with the finding of adducted thumbs in the prenatal setting is the determination of whether this finding is associated with an underlying genetic syndrome. The aim of the present study is to describe the characteristics and outcome of prenatal sonographic diagnosis of adducted thumbs. METHODS: A retrospective study was conducted over a period of 17 years in a tertiary referral center. All fetuses diagnosed prenatally with adducted thumbs comprised the study group. Prenatal sonographic assessment and neonatal outcome are presented. RESULTS: Six fetuses were evaluated for adducted thumbs over the 17-year period. In three cases, the parents elected termination of pregnancy for severe associated anomalies. In one case partial resolution was observed during the third trimester. Of the remaining two fetuses, one had a single umbilical artery and in the second the adducted thumbs were an isolated finding. Post-natal evaluation in both cases revealed bilateral adducted thumbs. Apart from orthopedic follow up no further interventions were needed. CONCLUSIONS: Prenatal diagnosis of adducted thumbs should be followed by a meticulous fetal ultrasound examination combined with genetic counseling. According to our cohort, if associated anomalies are excluded, isolated cases seem to have a favorable diagnosis.

Preaxial polydactyly following early gestational exposure to the smoothened agonist, SAG, in C57BL/6J mice.

BACKGROUND: While pharmacological activation of the Hedgehog (HH) signaling pathway may have therapeutic benefits for developmental and adult diseases, its teratogenic potential is of concern. The membrane molecule Smoothened (SMO) transduces HH signaling and can be acutely modulated by antagonists and agonists. The objective of the current experiments was to determine how maternal treatment with the Smo agonist, SAG, affects the developing limb. METHODS: Pregnant C57BL/6J mice received a single injection of SAG (15, 17, or 20 mg/kg, i.p.) or its vehicle on gestational day (GD) 9.25, the time of limb bud induction. Embryos were examined on GD 15 for gross dysmorphology and skeletal staining was performed to visualize the number and type of digits on the fore- and hindlimbs. Additionally, in situ hybridization was performed 4 hr after GD 9.25 SAG administration to determine SAG's effects on Gli1 and Gli2 mRNA expression. RESULTS: The most prevalent effect of SAG was the dose-dependent induction of pre-axial polydactyly; defects ranged from a broad thumb to the duplication of two finger-like digits on the preaxial side of the thumb. The highest SAG dose was effective in ca. 80% of the embryos and increased Gli1 and Gli2 mRNA expression in the limb bud, with Gli1 mRNA being the most upregulated. CONCLUSION: Preaxial polydactyly can be caused in the developing embryo by acute maternal administration of a Smo agonist that activates HH signaling. These results are consistent with the preaxial polydactyly induced in developmental disorders associated with mutations in HH signaling genes.Birth Defects Research 109:49-54, 2017. © 2016 Wiley Periodicals, Inc.

A very rare cause of acro-osteolysis: Hajdu-Cheney syndrome.

Acro-osteolysis is not uncommon and occurs in several conditions. Additional clinical and paraclinical findings and sometimes the performance of molecular tests can help to clarify the diagnosis. Here, we report the case of a 36-year-old woman who was referred to our department because of acute pain in the extremity of the left index finger. However, subsequent clinical examination also revealed short digits with pseudo-clubbing related to acro-osteolysis. Furthermore, severe osteoporosis, a moderate dysmorphic face, joint hypermobility, biological variables within normal ranges and her clinical history led us to consider the diagnosis of Hajdu-Cheney syndrome. Molecular analysis confirmed the diagnosis with the identification of a mutation in the NOTCH2 gene. The patient received bisphosphonate therapy, which resulted in some clinical and biological improvement 12 months later.

An atypical 0.73 MB microduplication of 22q11.21 and a novel SALL4 missense mutation associated with thumb agenesis and radioulnar synostosis.

We describe a 0.73 Mb duplication of chromosome 22q11.21 between LCR-B and LCR-D and a missense mutation in a conserved C2H2 zinc finger domain of SALL4 in a cognitively normal patient with multiple skeletal anomalies including radioulnar synostosis, thumb aplasia, butterfly vertebrae, rib abnormalities, and hypoplasia of the humeral and femoral epiphyses. 22q11.21 is a common site for microdeletions and their reciprocal microduplications as a result of non-allelic homologous recombination between its multiple low copy repeat regions (LCR). DiGeorge /Velocardiofacial syndrome (DG/VCFS) is classically caused by a 3 Mb deletion between LCR-A and LCR-D or a 1.5 Mb deletion between LCR-A and LCR-B. The reciprocal syndrome to DG/VCFS is the recently described 22q11.2 microduplication, which usually presents with the typical 3 Mb or 1.5 Mb duplication. Numerous atypical deletions and duplications have been reported between other LCRs. Typically, SALL4-related Duane-radial ray syndrome is caused by deletions or nonsense mutations; the only missense SALL4 mutation described prior was thought to result in gain of function and produced cranial midline defects. The skeletal anomalies presented in this report have not been previously described in association with 22q11.2 microduplication nor SALL4 mutations.

Incidence of Fanconi anemia in children with congenital thumb anomalies referred for diepoxybutane testing.

PURPOSE: Fanconi anemia (FA) is a rare genetic disorder of DNA repair that with near uniformity leads to bone marrow failure and resulting morbidity and mortality. Approximately 50% of FA patients are born with anomalies of the thumb or thumb and radius, and it has been recommended that all patients born with thumb anomalies undergo testing. However, the risk of FA in this population is unknown. We determined the incidence of FA in children with congenital thumb anomalies referred for FA testing and characterized those who tested positive. METHODS: We queried our database for patients who presented with congenital thumb anomalies and who underwent diepoxybutane (DEB) testing for FA between 1999 and 2008 at Children's Hospital Boston and the Dana-Farber Cancer Institute. RESULTS: During this time period, 543 congenital thumb anomaly patients (235 with thumb hypoplasia) presented to our institution. A total of 81 patients with thumb abnormalities underwent DEB testing. Six patients (7% of those tested; 1% of the total; 3% of thumb hypoplasia patients) had a positive DEB test consistent with the diagnosis of FA; all had other non-upper-extremity anomalies associated with FA. Of 6 FA patients, 5 had bilateral involvement; all had some degree of thumb hypoplasia (3 also had radial dysplasia). Mean age at testing was 2.6 years (SD 4.3). Most of the patients tested had multiple physical anomalies (n = 66). The anomaly distribution was: thumb hypoplasia and radial dysplasia (n = 29), thumb hypoplasia (n = 26), radial polydactyly (n = 12), radial polydactyly and radial dysplasia (n = 1), and proximally placed thumb and radial dysplasia (n = 1). Twelve patients had other thumb anomalies. CONCLUSIONS: Although the incidence of FA in patients with thumb anomalies may be low, patients with thumb hypoplasia and other physical findings associated with FA, specifically café au lait spots and short stature, appear to have an increased risk of FA. Because hand surgeons see these patients early in life, they have the opportunity to refer these patients for FA testing to initiate early education, family genetic counseling, and treatment if warranted. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

Familial occurrence of ptosis, nasal speech, prominent ears, hand anomalies and learning problems.

We describe a four-generation family in whom 5 members show the combination of a large head, ptosis, nasal speech that sometimes goes along with a cleft palate, full cheeks, small mouth, and prominent ears, and who also have learning problems. We evaluated three affected members in detail and found them to have in addition a partial cutaneous syndactyly between the third and fourth fingers, an increased distance between second and third finger, and a decreased smell. We have not been unable to find other patients described in literature with the same combination of features, and suggest this to represent a hitherto unrecognizable entity. Pattern of inheritance is likely to be autosomal dominant.

Craniosynostosis: A rare complication of pycnodysostosis.

Uncommon features of rare genetic disorders are often poorly known, as the likelihood of having them reported is low. We describe a 7-year-old boy with clinical and radiological diagnosis of pycnodysostosis, and c.436G>C (p.G146R) mutation in CSTK). He developed intracranial hypertension that required surgical decompression. Despite patent fontanels, the cause of the intracranial hypertension was identified to be a combination of coronal and metopic craniosynostoses. Intracranial hypertension and craniosynostosis have only been reported once in pycnodysostosis, which is on the contrary characterized by delayed closure of the sutures and persistence of open fontanels. Our observation confirms that intracranial hypertension represents a rare but life-threatening complication of pycnodysostosis. We strongly suggest including systematic examination of fundus oculi and monitoring of OFC in the systematic clinical follow-up of these patients.

Loss of dermatan-4-sulfotransferase 1 function results in adducted thumb-clubfoot syndrome.

Adducted thumb-clubfoot syndrome is an autosomal-recessive disorder characterized by typical facial appearance, wasted build, thin and translucent skin, congenital contractures of thumbs and feet, joint instability, facial clefting, and coagulopathy, as well as heart, kidney, or intestinal defects. We elucidated the molecular basis of the disease by using a SNP array-based genome-wide linkage approach that identified distinct homozygous nonsense and missense mutations in CHST14 in each of four consanguineous families with this disease. The CHST14 gene encodes N-acetylgalactosamine 4-O-sulfotransferase 1 (D4ST1), which catalyzes 4-O sulfation of N-acetylgalactosamine in the repeating iduronic acid-alpha1,3-N-acetylgalactosamine disaccharide sequence to form dermatan sulfate. Mass spectrometry of glycosaminoglycans from a patient's fibroblasts revealed absence of dermatan sulfate and excess of chondroitin sulfate, showing that 4-O sulfation by CHST14 is essential for dermatan sulfate formation in vivo. Our results indicate that adducted thumb-clubfoot syndrome is a disorder resulting from a defect specific to dermatan sulfate biosynthesis and emphasize roles for dermatan sulfate in human development and extracellular-matrix maintenance.

Autosomal dominant spondylocarpotarsal synostosis syndrome: phenotypic homogeneity and genetic heterogeneity.

Spondylocarpotarsal synostosis syndrome (SCT) (OMIM 272460), originally thought to be a failure of normal spine segmentation, is characterized by progressive fusion of vertebras and associates unsegmented bars, scoliosis, short stature, carpal and tarsal synostosis. Cleft palate, sensorineural or mixed hearing loss, joint limitation, clinodactyly, and dental enamel hypoplasia are variable manifestations. Twenty-five patients have been reported. Thirteen affected individuals were siblings from six families and four of these families were consanguineous. In four of those families, Krakow et al. [Krakow et al. (2004) Nat Genet 36:405-410] found homozygosity or compound heterozygosity for mutations in the gene encoding FLNB. This confirmed autosomal recessive inheritance of the disorder. We report on two new patients (a mother and her son) representing the first case of autosomal dominant inheritance. These patients met the clinical and radiological criteria for SCT and did not present any features which could exclude this diagnosis. Molecular analysis failed to identify mutations in NOG and FLNB. SCT is therefore, genetically heterogeneous. Both dominant and autosomal recessive forms of inheritance should be considered during genetic counseling.

The association of split hand foot malformation (SHFM) and congenital heart defects.

BACKGROUND: Split hand foot malformation (SHFM) (cleft hand, central ray deficiency) is a highly variable malformation that shows genetic heterogeneity with at least five loci mapped to date. SHFM occurs as an isolated finding or in association with other anomalies, including congenital heart defects (CHDs). METHODS: In total 48 SHFM1, 52 SHFM3, 48 SHFM4, 21 SHFM5, and four chromosome 8 patients were evaluated. In addition, we performed a literature review to identify "unmapped" SHFM patients with CHD to evaluate the various etiologies of this combination of findings. The London Dysmorphology Database also served as a resource to identify syndromes with this combination of phenotypic findings. Only patients presenting with both SHFM and CHD were included in the analysis. Classification of CHD among mapped and unmapped SHFM patients was performed utilizing the revised Clark classification. A closer inspection of the types of CHD found in this patient group was performed in order to investigate possible pathogenetic mechanisms. RESULTS: CHDs were found in 10% of SHFM1 patients, 47% of SHFM5 patients, but were not reported in SHFM2, SHFM4 patients, or patients mapped to chromosome 8. Forty-two syndromic cases and 15 cases of unrecognized syndromes were identified. CONCLUSIONS: The higher frequency of heart defects seen in SHFM1 and SHFM5 of the mapped patient group raises the question as to whether common mechanisms/genetic players are involved. Candidate genes for SHFM1 and SHFM5 include members of the DLX homeobox gene family.

EEC syndrome sans clefting: variable clinical presentations in a family.

Ectrodactyly, ectodermal dysplasia and cleft palate/lip syndrome (EEC) is a rare autosomal dominant syndrome with varied presentation and is actually a multiple congenital anomaly syndrome leading to intra- and interfamilial differences in severity because of its variable expression and reduced penetrance. The cardinal features include ectrodactyly, sparse, wiry, hypopigmented hair, peg-shaped teeth with defective enamel and cleft palate/lip. A family comprising father, daughter and son presented to us with split hand-split foot deformity (ectrodactyly), epiphora, hair changes and deafness with variable involvement in each family member.