Prenatal course of metaphyseal anadysplasia associated with homozygous mutation in MMP9 identified by exome sequencing.

Metaphyseal anadysplasia (MANDP) is a rare autosomal recessive form of skeletal dysplasia characterized by normal length at birth and transitory bowing of the legs. Although several families with MANDP have been reported, homozygous mutations in the matrix metalloproteinase type 9 (MMP9) gene have been described in only one consanguineous family, and thus the pre and postnatal phenotypic spectrum is still obscure. A clinically similar but more severe type is caused by autosomal-dominant inheritance and is caused by mutations in matrix metalloproteinase type 13 gene (MMP13). Here, we report the prenatal and early postnatal course of two affected sib fetuses with early sonographic evidence of long bone shortening and postnatally no metaphyseal changes. Whole-exome sequencing revealed homozygous mutation in MMP9 in both fetuses suggesting a diagnosis of MANDP. We propose that MANDP should be considered in pregnancies with early prenatal shortening of the long bones without associated finding of lethal skeletal dysplasias. In addition, the finding of homozygous mutation in non-consanguineous parents of Jewish-Caucasus ancestry may suggest unawareness of such relation or the occurrence of a founder mutation in this gene.

Darier disease in Israel: combined evaluation of genetic and neuropsychiatric aspects.

BACKGROUND: Darier disease (DD) is a rare genodermatosis caused by heterozygous mutations in the ATP2A2 gene. It has been associated with neuropsychiatric manifestations. OBJECTIVES: To investigate the genetic basis of Israeli patients with DD, and its association with the neuropsychiatric phenotype. METHODS: A cohort of 32 families comprising 74 affected individuals and 13 unaffected family members was recruited from the Haemek Dermatology Department and other dermatology clinics in Israel. The individuals were evaluated by detailed questionnaires, physical examination and genetic analysis. The main outcome measures were genetic mutations, psychiatric profile and their association. RESULTS: Twenty-three mutations in ATP2A2 were scattered over the entire gene, 14 of them novel. Two families shared the same mutation. Twenty-one patients (28%) had a history of psychiatric disorders, most of them mood disorders. Another seven patients (9%) were highly suspected of having a psychiatric disorder; 21 (28%) reported suicidal thoughts and five (7%) had attempted suicide. The psychiatric phenotype demonstrated inter- and intrafamilial variability, and was not associated with disease severity, family history of psychiatric disease or mutation location. CONCLUSIONS: The cohort demonstrated genetic heterogeneity with no mutation cluster along the gene, and a high prevalence of psychiatric disorders. Although no clear genotype-phenotype correlation was found, the results point to a major effect of genetic background on psychiatric phenotype, together with other modifiers.

Founder mutation for Huntington disease in Caucasus Jews.

Huntington disease (HD), an autosomal dominant disorder involving HTT, is characterized by chorea, psychiatric illness and cognitive decline. Diagnosis and age of onset depend on the degree of expansion of the trinucleotide CAG repeat within the gene. The prevalence of HD is known for Europeans but has not been studied in the Israeli population. Between 2006 and 2011 we diagnosed in our adult genetics clinic ten HD probands, nine of whom were Caucasus Jews (CJ) (Azerbaijani), and one Ashkenazi Jewish. We performed haplotype analysis to look for evidence of a founder mutation, and found that of the nine CJ, eight shared the same haplotype that was compatible with the A1 haplogroup. We calculated the coalescence age of the mutation to be between 80 and 150 years. Ninety percent of our HD patients are CJ, as are 27% of the HD patients in Israel, although the CJ comprise only 1.4% of the Israeli population. Our findings suggest a higher prevalence of HD among CJ compared to the general Israeli population and are consistent with a recent founder mutation. We recommend a higher degree of suspicion for HD in CJ with subtle clinical findings.

Early metabolic defects in Arab subjects with strong family history of Type 2 diabetes.

AIMS AND OBJECTIVE: It is widely accepted that the genetic make-up of the subject plays a pivotal role in the development of insulin resistance and ß cell failure. The objective of this study was to examine whether the same or distinct genetic backgrounds contribute to the development of insulin resistance and ß cell failure. METHODS: We examined insulin sensitivity and ß cell function in lean normal glucose tolerance subjects from 3 multigeneration Arab families. Families 1 and 2 had strong history of Type 2 diabetes (T2DM), while no member of family 3 had T2DM. RESULTS: Subjects in family 1 manifested increased basal plasma free fatty acid (FFA) concentration and impaired suppression of plasma FFA during the OGTT compared to subjects in family 3. Subjects in family 2 had comparable fasting plasma FFA and suppression of plasma FFA during the OGTT to family 3. Both the absolute plasma glucose concentrations, and incremental area under the plasma glucose curve (ΔG0-120) during the OGTT were comparable in subjects of families 1 and 2, and were decreased in subjects of family 3. Whole body and muscle insulin sensitivity were comparable in subjects from families 2 and 3, and both were significantly decreased in subjects of family 1. Beta cell function was comparable in subjects of families 1 and 3 and was significantly decreased in subjects of family 2. CONCLUSION: These results demonstrate that distinct genetic background contributes to the development of insulin resistance and ß cell dysfunction in Arab individuals.

Identification of 11 novel mutations in eight BBS genes by high-resolution homozygosity mapping.

BACKGROUND: Bardet-Biedl syndrome (BBS) is primarily an autosomal recessive disorder characterised by the five cardinal features retinitis pigmentosa, postaxial polydactyly, mental retardation, obesity and hypogenitalism. In addition, renal cysts and other anomalies of the kidney and urinary tract can be present. To date, mutations in 12 BBS genes as well as in MKS1 and CEP290 have been identified as causing BBS. The vast genetic heterogeneity of BBS renders molecular genetic diagnosis difficult in terms of the time and cost required to screen all 204 coding exons. METHOD: Here, the use of genome-wide homozygosity mapping as a tool to identify homozygous segments at known BBS loci, in BBS individuals from inbred and outbred background, is reported. RESULTS: In a worldwide cohort of 45 families, causative homozygous mutations in 20 families were identified via direct exon sequencing. Eleven of these mutations were novel, thereby increasing the number of known BBS mutations by 5% (11/218). CONCLUSIONS: Thus, in the presence of extreme genetic locus heterogeneity, homozygosity mapping provides a valuable approach to the molecular genetic diagnosis of BBS and will facilitate the discovery of novel pathogenic mutations.

Dependence of maternal serum [AFP]/[hCG] median ratios on age of gestation: comparison of trisomy 21 to euploid pregnancies.

BACKGROUND: Current risk calculations for trisomy 21, which are based on multiples of median (MoM), do not take into account possible differences between euploid and trisomy 21 pregnancies that may develop with gestational age. In order to optimize the predictive value of screening tests, we calculated the ratio between maternal serum concentration of alpha-fetoprotein (AFP) and that of human chorionic gonadotropin (hCG) in euploid and in trisomy 21 pregnancies. METHODS: The medians of the concentration ratios, [AFP]/[hCG] at 16-21 weeks of gestation, were plotted as a function of gestational age for 307 cases of trisomy 21 and were compared with the medians of 30 549 normal karyotype cases. RESULTS: [AFP]/[hCG] ratio medians were independent of body weight and maternal age. There was a significant difference in the [AFP]/[hCG] ratio when comparing trisomy 21 and euploid pregnancies at each week. This difference became greater with advancing gestational age (P < 0.01). CONCLUSION: There is a significant difference in ratios of [AFP]/[hCG] between euploid and trisomy 21 pregnancies, which may be used to improve detection rates of Down syndrome screening.

Mucolipidosis III type C: first-trimester biochemical and molecular prenatal diagnosis.

OBJECTIVES: Mucolipidosis IIIC (MLIIIC) is a rare autosomal recessive lysosomal storage disease resulting from defective mannose 6-phosphate-dependent lysosomal enzyme trafficking; mutations of the gamma subunit of N-acetylglucosamine-1 phosphotransferase (GINAcPT) were recently found to cause its pathogenesis. We report here for the first time prenatal diagnosis (PND) for MLIIIC by means of chorionic villous sampling (CVS). METHODS AND RESULTS: A fetus in a large Bedouin-Moslem family was found to be homozygous for the founder haplotype and the mutational SSCP pattern of MLIIIC. The diagnosis was confirmed by markedly reduced lysosomal enzyme activities in cultured chorionic villi. The molecular identification of the disease-causing mutation in this large Bedouin-Moslem kindred permitted, for the first time, identification of carriers and couples at risk. CONCLUSIONS: The feasibility of early PND for a progressive disabling disease is important for its prevention. Nevertheless, the feasibility of PND raises a serious dilemma since affected individuals might have a variable phenotype and the disease is progressive and non-lethal. In addition, religious and social constraints are important factors to be taken into consideration in the genetic counseling of couples at risk.

Familial lethal skeletal dysplasia with cloverleaf skull and multiple anomalies of brain, eye, face and heart: a new autosomal recessive multiple congenital anomalies syndrome.

We report on a 'new' lethal familial short-limb bone dysplasia associated with multiple anomalies in three sibs born to Arabic-Muslim consanguineous healthy parents. Clinical abnormalities included short limbs and short hands, cloverleaf skull, frontal bossing, wide anterior fontanel, hypertelorism, bilateral microphthalmia, cataract, low-set ears, narrow chest, ambiguous genitalia, cardiac ventricular septal defect (VSD) and agenesis of the corpus callosum. Radiological abnormalities included cloverleaf skull, hypoplastic clavicles and scapulae, thin, wavy cupped ribs, flat vertebral bodies with coronal clefting and several unossified vertebral pedicles and hypo-ossification of the pubic bone. The main changes noted in the long bones consisted of short-bowed long bones with abnormal metaphyses and unossified epiphyses. Chondro-osseous morphology documented degenerating chondrocytes with disorganization of the hypertrophied cartilage and short disorganized columns of hypertrophied areas. An autosomal recessive mode of inheritance seems most likely.

Heterozygous mutations in ANKH, the human ortholog of the mouse progressive ankylosis gene, result in craniometaphyseal dysplasia.

Craniometaphyseal dysplasia (CMD) is a bone dysplasia characterized by overgrowth and sclerosis of the craniofacial bones and abnormal modeling of the metaphyses of the tubular bones. Hyperostosis and sclerosis of the skull may lead to cranial nerve compressions resulting in hearing loss and facial palsy. An autosomal dominant form of the disorder (MIM 123000) was linked to chromosome 5p15.2-p14.1 (ref. 3) within a region harboring the human homolog (ANKH) of the mouse progressive ankylosis (ank) gene. The ANK protein spans the outer cell membrane and shuttles inorganic pyrophosphate (PPi), a major inhibitor of physiologic and pathologic calcification, bone mineralization and bone resorption. Here we carry out mutation analysis of ANKH, revealing six different mutations in eight of nine families. The mutations predict single amino acid substitutions, deletions or insertions. Using a helix prediction program, we propose for the ANK molecule 12 membrane-spanning helices with an alternate inside/out orientation and a central channel permitting the passage of PPi. The mutations occur at highly conserved amino acid residues presumed to be located in the cytosolic portion of the protein. Our results link the PPi channel ANK with bone formation and remodeling.

Achondroplasia in diverse Jewish and Arab populations in Israel: clinical and molecular characterization.

BACKGROUND: Achondroplasia is the most frequent form of disproportionate short stature, characterized by rhizomelic shortening of the limbs. This disorder is inherited as an autosomal dominant trait, although most of the cases are sporadic, a result of a de novo mutation. A recurrent glycine to arginine mutation at codon 380 (G380R) in the transmembrane domain of the fibroblast growth factor receptor 3 gene was found to cause achondroplasia among different populations. This is most uncommon in other autosomal dominant genetic diseases. OBJECTIVES: To determine whether this mutation is also common among Jewish patients from diverse ethnic groups and among the Arab population in Israel. METHODS: We examined the G380R mutation (G > A and G > C transition) and the mutation G375C (G > T transition at codon 375) in 31 sporadic patients and in one family diagnosed clinically to have achondroplasia. RESULTS: We found the G > A transition at codon 380 in 30 of our patients and the G > C transition in one patient. We were not able to detect any of the three mutations in two patients with an atypical form of achondroplasia. CONCLUSIONS: Our results further support the unusual observation that nucleotide 1138 of the FGFR3 gene is the most mutable nucleotide discovered to date across different populations.

DNA based prenatal testing for the skin blistering disorder epidermolysis bullosa simplex.

Epidermolysis bullosa simplex (EBS) is a skin fragility disorder in which mild physical trauma leads to blistering. The phenotype of the disorder is variable, from relatively mild affecting only the hands and/or feet, to very severe with widespread blistering. For the severest forms of EBS there is a demand for prenatal diagnosis which until now has involved a fetal skin biopsy in the second trimester. The identification of mutations in the genes encoding keratins K5 and K14 as the cause of EBS opens up the possibility of much earlier diagnosis of the disease. We report here four cases in which prenatal testing was performed. In three of the cases the genetic lesions were unknown at the start of the pregnancy, requiring the identification of the causative mutation prior to testing fetal DNA. In two of the four cases novel mutations were identified in K14 and in the two remaining families, a previously identified type of mutation was found. Fetal DNA, obtained by chorionic villus sampling or amniocentesis, was analysed for the identified mutations. Three of the DNA samples were found to be normal; a mutant K14 allele was identified in the fourth case and the pregnancy was terminated. These results demonstrate the feasibility of DNA-based prenatal testing for EBS in families where causative mutations can be found.

Osteosclerosis, hypoplastic nose, and proptosis (Raine syndrome): further delineation.

We describe a newborn girl with a lethal sclerosing bone dysplasia leading to prenatal skeletal alterations and microcephaly, proptosis, hypoplastic nose and midface, small jaw, cleft palate, hypertrophied gums, intracranial calcifications, and generalized osteosclerosis. There is a remarkable similarity between our patient and six previously reported infants subsequently categorized as having a distinct entity: Raine syndrome. Autosomal recessive inheritance is postulated based on parental consanguinity in several of the previous cases and in our patient.

Deletion mapping on chromosome 10p and definition of a critical region for the second DiGeorge syndrome locus (DGS2).

DiGeorge syndrome (DGS) is a developmental field defect, characterised by absent/hypoplastic thymus and parathyroid, and conotruncal heart defects, with haploinsufficiency loci at 22q (DGS1) and 10p (DGS2). We performed fluorescence in situ hybridisations (FISH) and polymerase chain reaction (PCR) analyses in 12 patients with 10p deletions, nine of them with features of DGS, and in a familial translocation 10p;14q associated with midline defects. The critical DGS2 region is defined by two DGS patients, and maps within a 1 cM interval including D10S547 and D10S585. The other seven DGS patients are hemizygous for both loci. The breakpoint of the reciprocal translocation 10p;14q maps at a distance of at least 12 cM distal to the critical DGS2 region. Interstitial and terminal deletions described are in the range of 10-50 cM and enable the tentative mapping of loci for ptosis and hearing loss, features which are not part of the DGS clinical spectrum.

Prevalence of glucocerebrosidase mutations in the Israeli Ashkenazi Jewish population.

Gaucher disease is the most prevalent inherited disease among Ashkenazi Jews. It is very heterogeneous due to a large number of mutations within the glucocerebrosidase gene, whose impaired activity is the cause for this disease. Aiming at determining Gaucher carrier frequency among the Ashkenazi Jewish population in Israel, 1,208 individuals were molecularly diagnosed for six mutations known to occur among Ashkenazi Jewish Gaucher patients, using the newly developed Pronto Gaucher kit. The following mutations were tested: N370S, 84GG, IVS2+1, D409H, L444P, and V394L. Molecular testing of these mutations also allows identification of the recTL allele. The results indicated that Gaucher carrier frequency is 1:17 within the tested population. The prevalence of N370S carriers is 1:17.5. This implies that approximately 1:1225 Ashkenazi Jews will be homozygous for the N370S mutation. Actually, in our study of 1,208 individuals one was found to be homozygous for the N370S mutation. The actual number of known Ashkenazi Jewish Gaucher patients with this genotype is much lower than that expected according to the frequency of the N370S mutation, suggesting a low penetrance of this mutation. Results of loading experiments in cells homozygous for the N370S mutation, as well as cells homozygous for the L444P and the D409H mutations, exemplified this phenomenon.

Genetic heterogeneity of Saethre-Chotzen syndrome, due to TWIST and FGFR mutations.

Thirty-two unrelated patients with features of Saethre-Chotzen syndrome, a common autosomal dominant condition of craniosynostosis and limb anomalies, were screened for mutations in TWIST, FGFR2, and FGFR3. Nine novel and three recurrent TWIST mutations were found in 12 families. Seven families were found to have the FGFR3 P250R mutation, and one individual was found to have an FGFR2 VV269-270 deletion. To date, our detection rate for TWIST or FGFR mutations is 68% in our Saethre-Chotzen syndrome patients, including our five patients elsewhere reported with TWIST mutations. More than 35 different TWIST mutations are now known in the literature. The most common phenotypic features, present in more than a third of our patients with TWIST mutations, are coronal synostosis, brachycephaly, low frontal hairline, facial asymmetry, ptosis, hypertelorism, broad great toes, and clinodactyly. Significant intra- and interfamilial phenotypic variability is present for either TWIST mutations or FGFR mutations. The overlap in clinical features and the presence, in the same genes, of mutations for more than one craniosynostotic condition-such as Saethre-Chotzen, Crouzon, and Pfeiffer syndromes-support the hypothesis that TWIST and FGFRs are components of the same molecular pathway involved in the modulation of craniofacial and limb development in humans.

Autosomal-recessive omodysplasia: prenatal diagnosis and histomorphometric assessment of the physeal plates of the long bones.

Second-semester ultrasonography of a female fetus documented short femora and humeri and dislocation of the radii. Based on the clinical and postmortem radiological findings, autosomal-recessive omodysplasia was diagnosed. The physeal plates of the long tubular bones were assessed by computer-assisted image analysis. The dimensions and orientation of the chondrocytic lacunae in the physeal plates of the omodysplastic fetus were compared with those in the physeal plates of fetuses without gross limb abnormalities (oligohydramnios, n = 2; hydrocephalus, n = 2; Down syndrome, n = 1). The pathological characteristics of the omodysplastic physeal plates were an expanded zone of proliferating cartilage and an increased number of closely packed, small chondrocytes. We propose that a genetic, functional deficiency of the physeal cells, underlying the short-limbed dwarfism of autosomal-recessive omodysplasia, is partially compensated, albeit ineffectively, by an increased number of small chondrocytes in the proliferating zone of the physeal plate.

Inherited inverted duplication of X chromosome in a male: report of a patient and review of the literature.

Nineteen cases of duplication of segments of the long arm of chromosome X have been published in 13 males and in 6 females. We report an additional case of a male with growth and mental retardation, growth hormone deficiency, compensated primary hypothyroidism, distinctive anomalies of the face, hypoplastic genitalia, and hypotonia in whom inverted duplication of a segment in the long arm of X chromosome was diagnosed, 46,Y, dup (X)(q21.2q13.3), and mosaicism was demonstrated in his mother's X chromosome. The rearranged segment was diagnosed utilizing high resolution G-band technique and FISH studies, using chromosome X total chromosome probe and DNA XIST probe. This appears to be the first report of a patient with duplication of Xq and hypothyroidism.