Al-Lamki et al. (2003) conducted a nationwide study on all patients diagnosed with HLH in Oman during the 5-year period 1997-2001. In 5 patients and their families, mutational analysis was made. A novel, identical missense mutation, causing transition of proline to threonine at codon 89 (265C to A) in exon 2 of the perforin gene was detected in two of these families, causing a transition of proline to threonine at codon 89. Interestingly, these two families were not related, and were from different tribes and regions. This mutation could not be detected in the other three families, as well as in 100 normal control chromosomes. Al-Lamki et al. (2003) concluded that the presence of such mutation in Omani families only, implied a founder effect in this population.

Muralitharan et al. (2005) studied the molecular defect of perforin gene as well as perforin cellular expression (to demonstrate the association between its level of expression and its function) in a one and a half month old Omani baby who had severe symptoms of familial hemophagocytic lymphohistocytosis (FHL). The infant, who was healthy after at full term delivery, was 44 days old when he presented with three days history of high grade fever and seizure-like history. There was no family history of a similar condition. Clinically, he was sick, febrile, tachycardic, tachypneic, and had enlarged liver and spleen (both of five cm below the costal margin. His condition deteriorated rapidly and he was ventilated. Investigations revealed pancytopenia (Hb of 8.9g/dl, WBC of 2.3 X 10(power 9)/L, platelets of 37 X 10(power 9)/L), deranged coagulation profile (PT of 32 seconds, APTT of 250 seconds, and fibrinogen of 0.3 g/dl), elevated serum ferritin of more than 3000 ng/ml, and evidence of hemophagocytic lymphohistocytosis (HLH) in bone marrow aspiration. Lumbar puncture was traumatic but otherwise unremarkable. The patient responded well to HLH-94 protocol and was extubated as he was diagnosed with HLH and was on continuation therapy. Genomic DNA was collected from the 13 family members (the parents, eight siblings and the patient, the paternal grandfather, and the maternal grandmother) and from 100 healthy Omani blood donors. Sequence analysis of the perforin gene coding region revealed a homozygous 12-base pair deletion (codon 284-287) resulting in the deletion of four amino acids in the membrane attack complex domain of the protein. This deletion maintains the reading frame of the perforin mRNA. Both parents and two unaffected sisters were heterozygotes for this molecular defect. The rest of the family members had the normal allele, which was further confirmed by PCR-RFLP using DdeI. Analysis of the sequence data revealed that the deletion was in a region that contained AAG sequence repeats (reflecting the possibility of replication slippage mechanism in generating this mutation). This mutation (deletion at nucleotide position 850-862) maintained the reading frame and resulted in deletion of four amino acid residues (Lys, Lys, His, Lys) from codon 284 to codon 287. Flow cytometry revealed the presence of perforin in 1.7% and 4.3% of the patient's CD3+/CD8+ and CD3+/CD56+ cytotoxic T-cells, respectively, which were within normal range of age-matched controls, and in 48% of his NK cells (when compared to 80% of cells of age-matched controls). Other family members had normal values of perforin cellular expression. These findings pointed out that some patients with FHL type 2 might have significant perforin expression in cytotoxic T cells and NK cells, reflecting the occurrence of perforin gene mutation despite the presence of normal perforin cellular expression. One year later, Muralitharan et al. (2006) studied the perforin A91V substitution in a population of 52 Omani children with childhood acute lymphoblastic leukemia (ALL), and nine children with Non-Hodgkin's Lymphoma (NHL). A total of 100 normal individuals were also studied to understand the genotype frequencies in the population. All patients and control subjects belonged to an ethnic Omani community with links to sub-Saharan eastern African states like Zanzibar. PCR was used to amplify the exons 2 and 3 of the PRF1 gene, and the amplicons were sequenced. Muralitharan et al. (2006) were unable to find a single patient or control subject with A91V substitution, indicating that this population does not show the substitution. One year later, Muralitharan et al. (2007) reported a comprehensive molecular analysis of 16 unrelated cases of FHL in ethnic Omanis. Using direct DNA sequencing analysis in 11 families, seven different mutations were identified in the coding region of the perforin gene, of which five were novel. In on-third of the cases of FHL in ethnic Omanis mutations in the Perforin gene could not be detected.

Elyamany et al., (2016) conducted a study between January 2005 and December 2014 in Saudi Arabia to analyze the data of Familial Hemophagocytic Lymphohistiocytosis (FHL) patients.  Mutations in the PRF1 genes were identified in two out of 12 patients with FHL.

In a retrospective study, Awan et al. 2013 analysed case histories of ten patients with hemophagocytic lymphohistiocytosis (HLH) seen at Pediatric Hematology/Oncology in Tawam Hospital, UAE between 2006 and 2012. All patients had prolonged fever, splenomegaly, and cytopenia, and 50% of patients displayed central nervous system-related symptoms. A Saudi patient (male, 8 months) was identified with mutation in PRF1  gene, which is associated with hemophagocytic lymphohistiocytosis, familial, 2.