Primary hyperoxaluria in populations of Pakistan origin: results from a literature review and two major registries

Jamsheer Talati, Aga Khan University
Sally-Anne Hulton, Birmingham Children’s Hospital, UK
Sander F. Garrelfs, Emma Children’s Hospital, Netherlands
Wajahat Aziz, Aga Khan University
Shoaib Rao, Aga Khan University
Amanullah Memon, Aga Khan University
Zafar Nazir, Aga Khan University
Syed Raziuddin Biyabani, Aga Khan University
Saqib Hamid Qazi, Aga Khan University
Iqbal Azam Syed, Aga Khan University
Aysha Habib, Aga Khan University
Jamil Ahmed, Aga Khan University
Lena Jafri, Aga Khan University
Mohammad Zeeshan, Aga Khan University

Abstract

Primary hyperoxalurias (PH) are devastating, autosomal recessive diseases causing renal stones. Undifferentiated hyperoxaluria is seen in up to 43% of Pakistani paediatric stone patients. High rates of consanguinity in Pakistan suggest significant local prevalence. There is no detailed information regarding number of cases, clinical features, and genetics in Pakistan-origin (P-o) patients. We reviewed available information on P-o PH patients recorded in the literature as well as from two major PH registries (the Rare Kidney Stone Consortium PH Registry (RKSCPHR) and the OxalEurope PH Registry (OxER); and the Aga Khan University Hospital in Pakistan. After excluding overlaps, we noted 217 P-o PH subjects (42 in OxER and 4 in RKSCPHR). Presentations were protean. Details of mutations were available for 94 patients of 201 who had genetic analyses. Unique mutations were noted. Mutation [c.508G>A (p. Gly170Arg)] (present in up to 25% in the West) was reported in only one case. In one series, only 30% had mutations on exons 1,4,7 of AGXT. Of 42 P-o patients in OxER, 52.4% were PH1, 45.2% PH2, and 2.4% PH3. Of concern is that diagnosis was made after renal transplant rejection (four cases) and on bone-marrow aspiration (in five). Lack of consideration of PH as a diagnosis, late diagnosis, and loss of transplanted kidneys mandates that PH be searched for diligently. Mutation analysis will need to extend to all exons and include PH 1,2,3. There is a need to spread awareness and identify patients through a scoring or screening system that alerts physicians to consider a diagnosis of PH.