A recognizable type of syndromic short stature with arthrogryposis caused by bi-allelic SEMA3A loss-of-function variants.

The semaphorins constitute a large family of secreted and membrane-associated proteins that regulate many developmental processes, including neural circuit assembly, bone formation and angiogenesis. Recently, bi-allelic loss-of-function variants in SEMA3A (semaphorin 3A) were identified in a single patient with a particular pattern of multiple congenital anomalies (MCA). Using homozygosity mapping combined with exome sequencing, we identified a homozygous SEMA3A variant causing a premature stop codon in an 8 year old boy with the same pattern of MCA. The phenotype of these patients is characterized by postnatal short stature, skeletal anomalies of the thorax, a minor congenital heart or vascular defect, camptodactyly, micropenis, and variable additional anomalies. Motor development is delayed in both patients, and intellectual development is delayed in one patient. Our observation of a second case supports the notion that bi-allelic mutations in SEMA3A cause an autosomal recessive type of syndromic short stature.

Triangular tibia with fibular aplasia associated with a microdeletion on 2q11.2 encompassing LAF4.

Nievergelt syndrome (NS) is an autosomal dominant mesomelic dysplasia characterized by specific deformities of the radius, ulna, fibula and a rhomboid shape of the tibia. Phenotypically overlapping conditions such as mesomelic dysplasia, Savarirayan-type (MIM 605274), have been described, but their pathogenesis also remains unknown. We report on a girl with fibular agenesis, severely abnormal, triangular tibiae, urogenital tract malformations, failure to thrive, convulsions and recurrent apnoeas leading to respiratory arrest at the age of 4 months. Her skeletal findings correspond to those of the mesomelic dysplasia, Savarirayan-type recently described in two patients. In addition to the skeletal findings, our patient had central nervous system manifestations and developmental anomalies of the urogenital tract. In the patient described in this study, array comparative genomic hybridization (CGH) analysis revealed a de novo interstitial microdeletion of 500 kb on chromosome 2q11.1 containing the LAF4/AFF3 (lymphoid-nuclear-protein-related AF4) gene. In situ hybridization analysis of Laf4 in mouse embryos revealed expression in the developing brain, in the limb buds and in the zeugopod corresponding to the limb phenotype. Haploinsufficiency for LAF4/AFF3 is associated with limb, brain and urogenital malformations and specific changes of the tibia that are part of the NS spectrum.

LDL receptor-related protein 5 (LRP5) affects bone accrual and eye development.

In humans, low peak bone mass is a significant risk factor for osteoporosis. We report that LRP5, encoding the low-density lipoprotein receptor-related protein 5, affects bone mass accrual during growth. Mutations in LRP5 cause the autosomal recessive disorder osteoporosis-pseudoglioma syndrome (OPPG). We find that OPPG carriers have reduced bone mass when compared to age- and gender-matched controls. We demonstrate LRP5 expression by osteoblasts in situ and show that LRP5 can transduce Wnt signaling in vitro via the canonical pathway. We further show that a mutant-secreted form of LRP5 can reduce bone thickness in mouse calvarial explant cultures. These data indicate that Wnt-mediated signaling via LRP5 affects bone accrual during growth and is important for the establishment of peak bone mass.

Persistent hyperplastic primary vitreous in a family with osteoporosis-pseudoglioma syndrome.

We had the opportunity to investigate the early abnormalities of the eyes in a family with osteoporosis-pseudoglioma syndrome. This syndrome combines severe premature osteoporosis with a bilateral eye disorder, leading to early onset blindness. Using colour doppler imaging in the 4-month-old girl from this affected family we demonstrated persistent hyperplastic primary vitreous in both eyes. Her brother's eyes had developed a partially calcified undefined mass. Our observation supports the hypothesis, that the disease gene may encode a matrix protein expressed in bone and eye.

Characterisation of X;17(q12;p13) translocation breakpoints in a female patient with hypomelanosis of Ito and choroid plexus papilloma.

An X;17 translocation breakpoint was characterised in a 5-year-old female with hypomelanosis of Ito (HI) who exhibits characteristic hypopigmented lesions, psychomotor retardation, and choroid plexus papilloma. A YAC clone containing the locus DXS1 from Xq12 was found by fluorescence in situ hybridisation to cross the translocation breakpoint. Cosmid clones positive for DXS1 were used to identify and clone the translocation junction fragment from the patient's DNA. A chromosome-17-specific DNA fragment was isolated and used to identify cosmid clones crossing the translocation from chromosome 17p13. Exon trapping identified two known genes from chromosome 17: FMR1L2 (the fragile X mental retardation syndrome like protein 2) and SHBG (human sex hormone-binding globulin). Mapping the FMR1L2 and SHBG genes showed that neither gene was disrupted by the translocation.

Deletion mapping on chromosome 17p in medulloblastoma.

Medulloblastoma is the most frequent paediatric brain tumour. Because of the uniform histology, a common genetic mechanism has been postulated. Loss of heterozygosity (LOH) studies support evidence that a candidate gene, which functions as a tumour-suppressor gene, is located in 17p13. Eighteen tumours were examined for loss of heterozygosity at 15 different loci at chromosome 17p. Nine of 18 (50%) tumours had allelic loss in 17p 13.3-13.2. The smallest region of overlap, which harbours the disease gene, includes markers from UT222 (D17S675) to UT49 (D17S731) and spans a region of less than 6 cM. Candidate genes within this region are HIC-1, a potential tumour-suppressor gene, and DPH2L, a gene that has been cloned from the ovarian critical region. The putative region excludes the p53 gene and the ABR gene, which have been favoured by others. LOH of chromosome 17p may be used as a new prognostic biological marker. Children with an allelic loss had a poorer prognosis than those patients without loss of heterozygosity (P<0.05).

Familial site-specific ovarian cancer is linked to BRCA1 on 17q12-21.

In a study of nine families with "site-specific" ovarian cancer (criterion: three or more cases of epithelial ovarian cancer and no cases of breast cancer diagnosed at age < 50 years) we have obtained evidence of linkage to the breast-ovarian cancer susceptibility gene, BRCA1 on 17q12-21. If the risk of cancer in these families is assumed to be restricted to the ovary, the best estimate of the proportion of families linked to BRCA1 is .78 (95% confidence interval .32-1.0). If predisposition to both breast and ovarian cancer is assumed, the proportion linked is 1.0 (95% confidence interval .46-1.0). The linkage of familial site-specific ovarian cancer to BRCA1 indicates the possibility of predictive testing in such families; however, this is only appropriate in families where the evidence for linkage to BRCA1 is conclusive.

Oral-facial-digital syndrome II. Transitional type between Mohr and Majewski syndrome: report of a new case with congenital stenosis of the trachea.

We present a female patient with laryngeal anomalies, tracheostenosis and pre- and postaxial polydactyly. Bilateral duplication of the hallux, polydactyly of hands, growth retardation and conductive hearing defect are consistent with oral-facial-digital (OFD) type II syndrome. Three similar cases of OFD syndrome with hypoplasia of the larynx, epiglottis and/or trachea without tibial dysplasia have been previously reported by Silengo and Temtamy and McKusick. The present patient adds one more case to this group of variants of OFD syndrome. We believe that those cases may be considered to form a separate subentity of OFD syndromes although overlapping features within the different subtypes make a precise classification very difficult.

Localisation of the breast-ovarian cancer susceptibility gene (BRCA1) on 17q12-21 to an interval of < or = 1 cM.

A breast-ovarian cancer susceptibility gene, BRCA1, which is responsible for disease in approximately 45% of breast cancer families and most families that contain breast and ovarian cancer, has been assigned by genetic linkage to 17q12-21. Here, we report the analysis of three marker-disease recombinants in families that contain breast and ovarian cancer, two of which strongly suggest a location for BRCA1 telomeric to D17S702, a microsatellite polymorphism, and a third which suggests a location centromeric to EDH17B, the gene encoding estradiol-17B dehydrogenase. If the interpretation of these recombinants is correct, the results localise BRCA1 to an interval of < or = 1 cM.

Hypomelanosis of Ito in a girl with plexus papilloma and translocation (X;17).

We describe a de novo constitutional (X;17) (q13;p13 translocation in a girl with the clinical features of hypomelanosis of to and plexus papilloma.

Familial cavernous angiomas of the brain: observations in a four generation family.

A family with a history of cavernous angiomas of the brain was investigated by MRI. The disease was present in four generations of the family and is consistent with autosomal dominant inheritance. Among affected individuals, there was considerable variability in the extent of intraparenchymal cavernomas and neurological symptoms as a result of bleeding events. Three siblings manifested with seizures, two affected persons were symptom free at the time of investigation, and one sibling had neurological symptoms without certain correlation with cavernomas. The disease appeared to have an earlier onset in younger generations.

[Penoscrotal hypospadias with XXYY chromosome pattern]. / Penoscrotale Hypospadie mit XXYY-Chromosomensatz.

This is the report of a boy, 2 years and 4 months of age who presented with an penoscrotal hypospadia with normal appearing testes. Physical examination and routine laboratory tests revealed--besides a broad base of the nose and clinodactyly--no abnormality. The boy exhibits a normal speech development with retarded global intellectual development. Investigation of the hormon status revealed a disturbance of testosteron secretion and a hypergonadotropic hypogonadism. Chromosomal analysis in lymphocyte cultures revealed a XXYY karyotyp. This chromosomal pattern is seen in 3% of patients with Klinefelter syndrom; the estimated frequency is 1 in 25,000 population. A combination of an XXYY chromosomal pattern with a penoscrotal hypospadia has not been reported in the literature so far.