Summary: The aim of this study was to determine the prevalence and trends of various types of consanguineous marriage among the Arab community in Israel over a long time period (1948–2007) by religion and educational level. Data were collected by face-to-face interview of 3173 Arab couples living in Israel in 2007 and 2008. The trend in consanguineous marriages was found to decrease significantly over successive time periods, from 42.5% to 30.9% (p=0.001), and the prevalence of first-cousin and closer marriages decreased, from 23% to 12.7%. Consanguinity was found to be significantly related to religion (p=0.001) and wife’s level of education (p=0.028).

PTRH2 is an evolutionarily highly conserved mitochondrial protein that belongs to a family of peptidyl-tRNA hydrolases. Recently, patients from two consanguineous families with mutations in the PTRH2 gene were reported. Global developmental delay associated with microcephaly, growth retardation, progressive ataxia, distal muscle weakness with ankle contractures, demyelinating sensorimotor neuropathy, and sensorineural hearing loss were present in all patients, while facial dysmorphism with widely spaced eyes, exotropia, thin upper lip, proximally placed thumbs, and deformities of the fingers and toes were present in some individuals. Here, we report a new family with three siblings affected by sensorineural hearing loss and peripheral neuropathy. Autozygosity mapping followed by exome sequencing identified a previously reported homozygous missense mutation in PTRH2 (c.254A>C; p.(Gln85Pro)). Sanger sequencing confirmed that the variant segregated with the phenotype. In contrast to the previously reported patient, the affected siblings had normal intelligence, milder microcephaly, delayed puberty, myopia, and moderate insensitivity to pain. Our findings expand the clinical phenotype and further demonstrate the clinical heterogeneity related to PTRH2 variants.

Despite the increased global prevalence and recognition of autistic spectrum disorder (ASD), it is still scarcely reported in the Arab world. Though Israel has a higher prevalence of ASD, a previous national survey of patients diagnosed between 1972 and 2004, demonstrated that 98% of them were of Jewish ancestry. The disproportional low number of Arab children with ASD in Israel is unclear but may reflect lower awareness and cultural bias. In the present study we collected clinical and demographic characteristics of 200 children with ASD from Arab and Jewish sectors in Israel that were evaluated in two child development centers. We compared the incidence and the medical comorbidity of autism between these two ethnics groups. The medical and psychiatric comorbidity profile in these children was similar to the worldwide published studies. In the present study the prevalence of autism in the Arab sector in Israel was similar to that of the Jewish sector. The Arab patients presented with more severe autistic manifestations and higher incidence of mental retardation, familial members with autism, and consanguinity (P<0.05), while in the Jewish sector milder forms (such as Asperger syndrome and PDD-NOS) were more frequent. This discrepancy might be explained by both genetic and cultural factors.