False regarding Primary hyperparathyroidism is

PHPT results from the enlargement of a single gland or parathyroid adenoma in approximately 80% of cases, multiple adenomas or hyperplasia in 15% to 20% of patients, and parathyroid carcinoma in 1% of patients. Most cases of PHPT are sporadic. It also occurs within the spectrum of a number of inherited disorders such as MEN1, MEN2A, isolated familial HPT, and familial HPT with jaw-tumour syndrome. All of these syndromes are inherited in an autosomal dominant fashion. PHPT is the earliest and most common manifestation of MEN1 and develops in 80% to 100% of patients by age 40 years old.