Further delineation of CANT1 phenotypic spectrum and demonstration of its role in proteoglycan synthesis.

Desbuquois dysplasia (DD) is characterized by antenatal and postnatal short stature, multiple dislocations, and advanced carpal ossification. Two forms have been distinguished on the basis of the presence (type 1) or the absence (type 2) of characteristic hand anomalies. We have identified mutations in calcium activated nucleotidase 1 gene (CANT1) in DD type 1. Recently, CANT1 mutations have been reported in the Kim variant of DD, characterized by short metacarpals and elongated phalanges. DD has overlapping features with spondyloepiphyseal dysplasia with congenital joint dislocations (SDCD) due to Carbohydrate (chondroitin 6) Sulfotransferase 3 (CHST3) mutations. We screened CANT1 and CHST3 in 38 DD cases (6 type 1 patients, 1 Kim variant, and 31 type 2 patients) and found CANT1 mutations in all DD type 1 cases, the Kim variant and in one atypical DD type 2 expanding the clinical spectrum of hand anomalies observed with CANT1 mutations. We also identified in one DD type 2 case CHST3 mutation supporting the phenotype overlap with SDCD. To further define function of CANT1, we studied proteoglycan synthesis in CANT1 mutated patient fibroblasts, and found significant reduced GAG synthesis in presence of ß-D-xyloside, suggesting that CANT1 plays a role in proteoglycan metabolism.

Prenatal diagnosis of beta-thalassemia in the West Bank and Gaza.

OBJECTIVE: This study focuses on the genetic aspect of beta-thalassemia among 88 at risk couples from the West Bank and Gaza, and the attitude of these couples toward prenatal diagnosis and its outcome as a preventive method. METHODS: We tested 130 prenatal samples for beta-thalassemia during the period from January 1999 to July 2005. We performed prenatal diagnosis in these cases using the amplification refractory mutation system, as well as beta-globin gene sequencing as a conformational method. We drew a chorionic villus sample (CVS) for 1st trimester pregnant women and amniotic fluid (AF) for those in the 2nd trimester depending on the stage the pregnant woman contacted our lab. RESULTS: The DNA analysis of 130 prenatal samples revealed 25 (19.2%) cases of beta-thalassemia major and 67 (51.5%) cases of beta-thalassemia carriers, while the remaining 38 (29.2%) were normal. The 25 affected fetuses were aborted according to the wishes of the parents. In the tested 88 couples, 14 mutations of beta-thalassemia were identified. These mutations and their frequencies were: IVSI-110 (22.2%), IVSI-6 (13.6%), Cd37 (12%), IVSI-I (9.7%), IVSII-1 (6.2%), Cd39 (9%), Cd6 (sickle cell mutation) (8.5%), Cd5 (8%), Cd8/9 (2.8%), Cd106/107 (2.8%), -30 promoter (1.1%), -88 promoter (1.1%), IVSI (-1) (2.3%) and IVSI-5 (0.6%). We found that in 77.3% of the couples, both the mother and the father carry the same type of mutation while 22.7% of them carry different mutations. We found 77.9% consanguinity among the couples CONCLUSION: We found very good acceptability for prenatal diagnosis in beta-thalassemia afflicted families. All couples with affected fetuses opted for abortion. The spectrum of mutations in the tested couples revealed several similarities to neighboring countries with -88 promoter mutation reported for the first time in our region.

Genetic screening of familial Mediterranean fever mutations in the Palestinian population.

OBJECTIVE: To investigate the spectrum of mutations and genotypes in the pyrin gene in familial Mediterranean fever (FMF) patients. METHODS: Blood samples of 511 suspected FMF patients, received from the Molecular Genetics Laboratory, Makassed Islamic Charitable Hospital, Mount Olives, Jerusalem during the period from June 1999 to August 2004, were investigated by genotyping 24 different MEFV mutations. RESULTS: Our work revealed the presence of 14 different mutations from the identified 24 mutations in the gene which are assembled in 6 homozygous, 9 heterozygous and 16 compound heterozygous genotypes. The homozygous genotypes represent the predominant format among our patients representing approximately 38% of the revealed genotypes. Interestingly, in 94 (31.4%) of the tested subjects, only one mutation in the pyrin gene could be identified while the other mutant allele remains unidentified. Moreover, the genotype of 3 (1%) patients revealed the presence of triplet mutations in the pyrin gene. CONCLUSION: The results of our study clearly suggest that the origin of FMF among the Palestinian population is mostly homozygous. The identification of a significant number of patients with one known mutation indicates potentially the presence of new mutations in the gene which will be investigated in the future.

A novel mutation in TTC19 associated with isolated complex III deficiency, cerebellar hypoplasia, and bilateral basal ganglia lesions.

Isolated complex III (cIII) deficiency is a rare biochemical finding in mitochondrial disorders, mainly associated with mutations in mitochondrial DNA MTCYB gene, encoding cytochrome b, or in assembly factor genes (BCS1L, TTC19, UQCC2, and LYRM7), whereas mutations in nuclear genes encoding cIII structural subunits are extremely infrequent. We report here a patient, a 9 year old female born from first cousin related parents, with normal development till 18 months when she showed unsteady gait with frequent falling down, cognitive, and speech worsening. Her course deteriorated progressively. Brain MRI showed cerebellar vermis hypoplasia and bilateral lentiform nucleus high signal lesions. Now she is bed ridden with tetraparesis and severely impaired cognitive and language functions. Biochemical analysis revealed isolated cIII deficiency in muscle, and impaired respiration in fibroblasts. We identified a novel homozygous rearrangement in TTC19 (c.213_229dup), resulting in frameshift with creation of a premature termination codon (p.Gln77Argfs*30). Western blot analysis demonstrated the absence of TTC19 protein in patient's fibroblasts, while Blue-Native Gel Electrophoresis analysis revealed the presence of cIII-specific assembly intermediates. Mutations in TTC19 have been rarely associated with mitochondrial disease to date, being described in about ten patients with heterogeneous clinical presentations, ranging from early onset encephalomyopathy to adult forms with cerebellar ataxia. Contrariwise, the biochemical defect was a common hallmark in TTC19 mutant patients, confirming the importance of TTC19 in cIII assembly/stability. Therefore, we suggest extending the TTC19 mutational screening to all patients with cIII deficiency, independently from their phenotypes.

Propionic acidemia mimicking diabetic ketoacidosis.

Propionic acidemia manifesting with hyperglycemia is rare. Few cases have been reported mainly of the neonatal-onset form associated with high mortality. We report a 9-month-old Palestinian boy who manifested with coma, severe hyperglycemia and ketoacidosis mimicking diabetic ketoacidosis. Family history of unexplained infant deaths was helpful in reaching the correct diagnosis. In response to therapy, the patient regained consciousness without neurologic deficits and had normal examination. This is, to our knowledge, the first case report of late-onset propionic acidemia that had this presentation and survived.