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Ragate DC, Memon SS, Karlekar M, Lila AR, Sarathi V, Jamale T, Thakare S, Patil VA, Shah NS, Bandgar TR. Inherited Fanconi renotubular syndromes: unveiling the intricacies of hypophosphatemic rickets/osteomalacia. J Bone Miner Metab 2024; 42:155-165. [PMID: 38310177 DOI: 10.1007/s00774-023-01490-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 11/16/2023] [Indexed: 02/05/2024]
Abstract
INTRODUCTION Fanconi renotubular syndromes (FRTS) are a rare group of inherited phosphaturic disorders with limited Indian as well as global data on this condition. Here, we describe the experience of a single Endocrinology center from Western India on FRTS. MATERIALS AND METHODS Comprehensive clinical, biochemical, radiological, management, and genetic details of FRTS patients managed between 2010 and 2023 were collected and analyzed. RESULTS FRTS probands had mutations (eight novel) in six genes [CLCN5 (n = 4), SLC2A2 (n = 2), GATM, EHHADH, HNF4A, and OCRL (1 each)]. Among 15 FRTS patients (11 families), rickets/osteomalacia was the most common (n = 14) presentation with wide inter- and intra-familial phenotypic variability. Delayed diagnosis (median: 8.8 years), initial misdiagnosis (8/11 probands), and syndrome-specific discriminatory features (8/11 probands) were commonly seen. Hypophosphatemia, elevated alkaline phosphatase, normal parathyroid hormone (median: 36 pg/ml), high-normal/elevated 1,25(OH)2D (median: 152 pg/ml), hypercalciuria (median spot urinary calcium to creatinine ratio: 0.32), and variable proximal tubular dysfunction(s) were observed. Elevated C-terminal fibroblast growth factor 23 in two probands was misleading, till the genetic diagnosis was reached. Novel observations in our FRTS cohort were preserved renal function (till sixth decade) and enthesopathy in FRTS1 and FRTS3 families, respectively. CONCLUSION Our findings underscore frequent under- and misdiagnosis of FRTS; hence, a high index of suspicion for FRTS in phosphopenic rickets/osteomalacia, with early consideration of genetic testing is essential to ensure timely diagnosis of FRTS. The novel variants and phenotypic manifestations described here expand the disease spectrum of FRTS.
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Affiliation(s)
- Divya C Ragate
- Department of Endocrinology OPD, Seth G.S. Medical College and KEM Hospital, Parel, Mumbai, Maharashtra, 4000012, India
| | - Saba Samad Memon
- Department of Endocrinology OPD, Seth G.S. Medical College and KEM Hospital, Parel, Mumbai, Maharashtra, 4000012, India.
| | - Manjiri Karlekar
- Department of Endocrinology OPD, Seth G.S. Medical College and KEM Hospital, Parel, Mumbai, Maharashtra, 4000012, India
| | - Anurag Ranjan Lila
- Department of Endocrinology OPD, Seth G.S. Medical College and KEM Hospital, Parel, Mumbai, Maharashtra, 4000012, India
| | - Vijaya Sarathi
- Department of Endocrinology, Vydehi Institute of Medical Sciences and Research Centre, Bangalore, Karnataka, India
| | - Tukaram Jamale
- Department of Nephrology, Seth G.S. Medical College and KEM Hospital, Mumbai, Maharashtra, India
| | - Sayali Thakare
- Department of Nephrology, Seth G.S. Medical College and KEM Hospital, Mumbai, Maharashtra, India
| | - Virendra A Patil
- Department of Endocrinology OPD, Seth G.S. Medical College and KEM Hospital, Parel, Mumbai, Maharashtra, 4000012, India
| | - Nalini S Shah
- Department of Endocrinology OPD, Seth G.S. Medical College and KEM Hospital, Parel, Mumbai, Maharashtra, 4000012, India
| | - Tushar R Bandgar
- Department of Endocrinology OPD, Seth G.S. Medical College and KEM Hospital, Parel, Mumbai, Maharashtra, 4000012, India
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Krishna Prasad H, Bajpai A. Pediatric Endocrinology in Office Practice - The Way Forward. Indian J Pediatr 2023; 90:572-573. [PMID: 37140837 DOI: 10.1007/s12098-023-04618-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 04/13/2023] [Indexed: 05/05/2023]
Affiliation(s)
- Hemchand Krishna Prasad
- Department of Pediatric Endocrinology, Mehta Multispeciality Hospitals India Pvt. Ltd, 2, Mc Nichol's Road, Chetpet, Chennai, Tamil Nadu, India.
| | - Anurag Bajpai
- Department of Pediatric Endocrinology, Regency Center for Diabetes, Endocrinology & Research, Kanpur, Uttar Pradesh, India
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