ICD10 code of Pseudohypoparathyroidism and ICD9 code

The ICD-10 code for Pseudohypoparathyroidism is E20.1, while the corresponding ICD-9 code is 252.1. These classification codes are essential for medical billing, insurance authorization, and clinical documentation for patients living with this complex endocrine condition.

What is the clinical nature of Pseudohypoparathyroidism?

Pseudohypoparathyroidism is a rare genetic disorder characterized by end-organ resistance to parathyroid hormone (PTH). Unlike hypoparathyroidism, where the body fails to produce enough hormone, in Pseudohypoparathyroidism, the body produces sufficient—or even elevated—levels of PTH, but the kidneys and bones fail to respond to the signal. This leads to the hallmark clinical findings of low serum calcium (hypocalcemia) and high serum phosphate (hyperphosphatemia). At DiseaseMaps.org, we have seen 42 people with Pseudohypoparathyroidism join our community, highlighting the importance of shared experiences in managing such a rare diagnosis.

How are the genetic causes and inheritance patterns classified?

The genetic basis of Pseudohypoparathyroidism is primarily linked to mutations in the GNAS gene, which encodes the alpha subunit of the stimulatory G-protein (Gsα). Because the inheritance is complex and often involves genomic imprinting, the clinical presentation varies significantly based on whether the mutation is inherited from the mother or the father. This genetic heterogeneity is why clinical geneticists classify Pseudohypoparathyroidism into several subtypes, including:

• Type 1a: Often presents with Albright Hereditary Osteodystrophy (AHO), characterized by short stature, round face, and shortened fourth/fifth metacarpals.


• Type 1b: Generally presents with PTH resistance without the physical features of AHO.


• Type 1c: Shares clinical features with 1a but with different biochemical G-protein activity levels.


• Type 2: A rarer form where PTH resistance exists without the typical physical stigmata.

How is the diagnosis confirmed in clinical practice?

Diagnosing Pseudohypoparathyroidism requires a careful evaluation of biochemical markers and, when possible, molecular genetic testing. Physicians typically look for the combination of hypocalcemia, hyperphosphatemia, and elevated serum PTH levels in the absence of vitamin D deficiency or renal failure. Because Pseudohypoparathyroidism can be confused with other metabolic bone diseases, clinical specialists often perform a urinary cAMP response test following an exogenous PTH injection to confirm the G-protein signaling defect.

Living with the condition: Psychological and social support

Receiving a diagnosis of Pseudohypoparathyroidism can be overwhelming for patients and caregivers alike. The chronic nature of the condition requires lifelong monitoring of calcium and vitamin D levels to prevent complications like seizures or basal ganglia calcification. Connecting with others who understand the burden of frequent blood draws and the nuances of hormone therapy is a vital part of the therapeutic journey. Our community platform serves as a space where members share how they navigate the daily realities of living with this rare endocrine disorder.

Next steps

• Consult an endocrinologist specializing in calcium and bone metabolism for long-term management.


• Schedule an appointment with a clinical geneticist to discuss inheritance patterns and family screening.


• Join the Pseudohypoparathyroidism community at DiseaseMaps.org to connect with other patients and caregivers.


• Keep a detailed log of your calcium, phosphorus, and PTH lab results to share with your multidisciplinary care team.

Medical disclaimer: This content is for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment; always seek the advice of your physician or qualified health provider with any questions regarding a medical condition.

References

• Orphanet: Pseudohypoparathyroidism (ORPHA:748)


• NIH Genetic and Rare Diseases Information Center (GARD): Pseudohypoparathyroidism


• OMIM (Online Mendelian Inheritance in Man): #103580 (PHP1A)


• The MAGIC Foundation: Resources for Endocrine Disorders