Types of Diabetes Mellitus – A to Z

Last updated: February 8, 2026Reviewed date: February 8, 2026Reading time: 5 min read
Patient Tools

Read, save, and share this guide

Use these quick tools to make this medical article easier to read, print, save, or share with a family member.

Patient Mode

Understand this article easily

Switch between simple English and easy Bangla patient notes. This is for education and does not replace a doctor consultation.

Types of Diabetes Mellitus /Diabetes Mellitus (DM) is a metabolic disease, involving inappropriately elevated blood glucose levels. DM has several categories, including type 1, type 2, maturity-onset diabetes of the young (MODY), gestational diabetes, neonatal diabetes, and secondary causes due to endocrinopathies, steroid use, etc....

For severe symptoms, danger signs, pregnancy, child illness, or sudden worsening, seek urgent medical care.

বাংলা রোগী নোট এখনো যোগ করা হয়নি। পোস্ট এডিটরে “RX Bangla Patient Mode” বক্স থেকে সহজ বাংলা সারাংশ যোগ করুন।

এই তথ্য শিক্ষা ও সচেতনতার জন্য। এটি ডাক্তারি পরীক্ষা, রোগ নির্ণয় বা প্রেসক্রিপশনের বিকল্প নয়।

Article Summary

Types of Diabetes Mellitus /Diabetes Mellitus (DM) is a metabolic disease, involving inappropriately elevated blood glucose levels. DM has several categories, including type 1, type 2, maturity-onset diabetes of the young (MODY), gestational diabetes, neonatal diabetes, and secondary causes due to endocrinopathies, steroid use, etc. The main subtypes of DM are Type 1 Diabetes Mellitus (T1DM) and Type 2 Diabetes Mellitus (T2DM), which classically result...

Key Takeaways

  • This article explains Types of Diabetes Mellitus in simple medical language.
Educational health guideWritten for patient understanding and clinical awareness.
Reviewed content workflowUse writer and reviewer profiles for stronger trust.
Emergency safety firstUrgent warning signs are highlighted below.

Seek urgent medical care if you notice

These warning signs are general safety guidance. Local emergency numbers and clinical judgment should always come first.

  • Severe symptoms, breathing difficulty, fainting, confusion, or rapidly worsening illness.
  • New weakness, severe pain, high fever, or symptoms after a serious injury.
  • Any symptom that feels urgent, unusual, or unsafe for the patient.
1

Emergency now

Use emergency care for severe, sudden, rapidly worsening, or life-threatening symptoms.

2

See a doctor

Book a professional medical evaluation if symptoms persist, worsen, recur often, affect daily activities, or occur in a high-risk patient.

3

Learn safely

Use this article to understand possible causes, tests, treatment options, prevention, and questions to ask your clinician.

Before reading

RX Patient Tools

Use these quick guides before reading the article, or return to them when you need help preparing questions for a doctor.

Start here Choose the right pathway for symptoms, reports, medicines, or urgent warning signs. Disease article roadmap Read this topic step by step: meaning, symptoms, warning signs, diagnosis, treatment, prevention, and follow-up. Treatment planner Prepare questions about treatment choices, benefits, risks, side effects, and follow-up. Family & caregiver guide Organize symptoms, reports, medicines, questions, and follow-up safely. Nutrition & diet guide Prepare food, hydration, supplement, and medicine-timing questions safely. Prevention guide Organize risk factors, protective habits, screening, and warning signs. Recovery guide Prepare a safe plan for activity, rehabilitation, warning signs, and follow-up.
Definition

Types of insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।" data-rx-term="diabetes" data-rx-definition="Diabetes is a condition where blood sugar stays too high because insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।">Diabetes Mellitus /insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।" data-rx-term="diabetes" data-rx-definition="Diabetes is a condition where blood sugar stays too high because insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।">Diabetes Mellitus (DM) is a metabolic disease, involving inappropriately elevated blood glucose levels. DM has several categories, including type 1, type 2, maturity-onset diabetes of the young (MODY), gestational diabetes, neonatal diabetes, and secondary causes due to endocrinopathies, steroid use, etc. The main subtypes of DM are Type 1 Diabetes Mellitus (T1DM) and Type 2 Diabetes Mellitus (T2DM), which classically result from defective insulin secretion (T1DM) and/or action (T2DM). T1DM presents in children or adolescents, while T2DM is thought to affect middle-aged and older adults who have prolonged hyperglycemia due to poor lifestyle and dietary choices. The pathogenesis for T1DM and T2DM is drastically different, and therefore each type has various etiologies, presentations, and treatments.

Types of insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।" data-rx-term="diabetes" data-rx-definition="Diabetes is a condition where blood sugar stays too high because insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।">Diabetes Mellitus

DM is broadly classified into three types by etiology and clinical presentation, type 1 insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।" data-rx-term="diabetes" data-rx-definition="Diabetes is a condition where blood sugar stays too high because insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।">diabetes, type 2 diabetes, and gestational diabetes (GDM). Some other less common types of diabetes include monogenic diabetes and secondary diabetes.

Type 1 insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।" data-rx-term="diabetes" data-rx-definition="Diabetes is a condition where blood sugar stays too high because insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।">Diabetes Mellitus (T1DM)

  • Type 1 insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।" data-rx-term="diabetes" data-rx-definition="Diabetes is a condition where blood sugar stays too high because insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।">diabetes mellitus (T1DM) accounts for 5% to 10% of DM and is characterized by autoimmune destruction of insulin-producing beta cells in the islets of the pancreas. As a result, there is an absolute deficiency of insulin. A combination of genetic susceptivity and environmental factors such as viral infection, toxins, or some dietary factors have been implicated as triggers for autoimmunity. T1DM is most commonly seen in children and adolescents though it can develop at any age.

Type 2 insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।" data-rx-term="diabetes" data-rx-definition="Diabetes is a condition where blood sugar stays too high because insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।">Diabetes Mellitus

  • Type 2 insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।" data-rx-term="diabetes" data-rx-definition="Diabetes is a condition where blood sugar stays too high because insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।">diabetes mellitus (T2DM) accounts for around 90% of all cases of diabetes. In T2DM, the response to insulin is diminished, and this is defined as insulin resistance. During this state, insulin is ineffective and is initially countered by an increase in insulin production to maintain glucose homeostasis, but over time, insulin production decreases, resulting in T2DM. T2DM is most commonly seen in persons older than 45 years. Still, it is increasingly seen in children, adolescents, and younger adults due to rising levels of obesity, physical inactivity, and energy-dense diets.

Gestational insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।" data-rx-term="diabetes" data-rx-definition="Diabetes is a condition where blood sugar stays too high because insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।">Diabetes Mellitus

  • Hyperglycaemia, which is first detected during pregnancy, is classified as gestational insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।" data-rx-term="diabetes" data-rx-definition="Diabetes is a condition where blood sugar stays too high because insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।">diabetes mellitus (GDM), also known as hyperglycemia in pregnancy. Although it can occur anytime during pregnancy, GDM generally affects pregnant women during the second and third trimesters. According to the American Diabetes Association (ADA), GDM complicates 7% of all pregnancies. Women with GDM and their offspring have an increased risk of developing type 2 diabetes mellitus in the future.

Monogenic insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।" data-rx-term="diabetes" data-rx-definition="Diabetes is a condition where blood sugar stays too high because insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।">Diabetes

  • A single genetic mutation in an autosomal dominant gene causes this type of insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।" data-rx-term="diabetes" data-rx-definition="Diabetes is a condition where blood sugar stays too high because insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।">diabetes. Examples of monogenic diabetes include conditions like neonatal diabetes mellitus and maturity-onset diabetes of the young (MODY). Around 1% to 5% of all diabetes cases are due to monogenic diabetes. MODY is a familial disorder and usually presents under the age of 25 years.

Secondary insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।" data-rx-term="diabetes" data-rx-definition="Diabetes is a condition where blood sugar stays too high because insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।">Diabetes

  • Secondary insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।" data-rx-term="diabetes" data-rx-definition="Diabetes is a condition where blood sugar stays too high because insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।">diabetes is caused due to the complication of other diseases affecting pancreas (for example, pancreatitis), hormone disturbances (for example, Cushing’s disease), or due to drugs (for example, corticosteroids).

Other specific types

Genetic defects of beta -cell function

  • Chromosome 20q, HNF-4 alpha (MODY1)
  • Chromosome 7p, glucokinase (MODY2)
  • Chromosome 12q, HNF-1 alpha (MODY3)
  • Chromosome 13q, insulin promoter factor-1 (MODY4)
  • Chromosome 17q, HNF-1 beta (MODY5)
  • Chromosome 2q, Neurogenic differentiation1 (MODY 6)
  • Chromosome 9, carboxyl ester lipase (MODY 7)
  • Transient Neonatal Diabetes (Chromosome 6p22 or 6p24, ZAC encoding zinc finger protein)
  • Permanent Neonatal Diabetes (Chromosome 11p15, usually KCNJ11 encoding for KIR6.2 subunit of the beta-cell KATP channel)
  • Mitochondrial DNA
  • Others

Genetic defects in insulin action

  • Type A insulin resistance
  • Leprechaunism
  • Rabson-Mendenhall syndrome
  • Lipoatrophic diabetes
  • Others

Diseases of the exocrine pancreas

  • Pancreatitis
  • Trauma/pancreatectomy
  • Neoplasia
  • Cystic fibrosis
  • Hemochromatosis
  • Fibrocalculous pancreatopathy
  • Others

Endocrinopathies

  • Acromegaly
  • Cushing’s syndrome
  • Glucagonoma
  • Pheochromocytoma
  • Hyperthyroidism
  • Somatostatinoma
  • Aldosterone
  • Others

Drug- or chemical-induced

  • Vacor
  • Pentamidine
  • Nicotinic acid
  • Glucocorticoids
  • Thyroid hormone
  • Diazoxide
  • beta-adrenergic agonists
  • Thiazides
  • Dilantin(phenytoin)
  • alpha-interferon

Infections

  • Congenital rubella
  • Cytomegalovirus
  • Others

Uncommon forms of immune-mediated diabetes

  • “Stiff-man” syndrome
  • Anti-insulin receptor antibodies
  • Others

Other genetic syndromes sometimes associated with diabetes

  • Down’s syndrome
  • Klinefelter’s syndrome
  • Turner’s syndrome
  • Wolfram’s syndrome
  • Friedreich’s ataxia
  • Huntington’s chorea
  • Laurence-Moon-Bieldel syndrome
  • Myotonic dystrophy
  • Porphyria
  • Prader-Willi syndrome
  • Post-transplant

Types of According to the Diagnosis of GDM 

“One- Step” Diagnosis- 75 gram glucose tolerance test (IADPSG Consensus)
TIME PLASMA GLUCOSE*
Fasting ≥92 mg/dl (5.1 mmol/L)
1-hour ≥180 mg/dl (10.0mmol/L)
2-hour ≥153 mg/dl (8.5 mmol/L)
“Two-Step” Diagnosis- (NIH Consensus)
Step 1: Perform 50 gram glucose load test (nonfasting)
TIME PLASMA GLUCOSE
1-hour ≥140 mg/dl (7.8 mmol/L)
IF POSITIVE, STEP 2: 100 gram glucose tolerance test
Carpenter/Coustan NDDG
TIME PLASMA GLUCOSE+ TIME PLASMA GLUCOSE+
Fasting ≥95 mg/dl (5.3 mmol/L) Fasting ≥105 mg/dl (5.8 mmol/L)
1-hour ≥180 mg/dl (10.0 mmol/L) 1-hour ≥190 mg/dl (10.6 mmol/L)
2-hour ≥155 mg/dl (8.6 mmol/L) 2-hour ≥165 mg/dl (9.2 mmol/L)
3-hour ≥140 mg/dl (7.8 mmol/L) 3-hour ≥145 mg/dl (8.0 mmol/L)
*One abnormal value is sufficient to make the diagnosis of GDM. The test should be done in the morning after at least 8 hour fast. +Two abnormal values establishes the diagnosis of GDM. NDDG=National Diabetes Data Group.

References

Doctor visit helper

Prepare before seeing a doctor

A simple rural-patient checklist to help you explain symptoms clearly, ask better questions, and avoid unsafe self-treatment.

Safety note: This is not a prescription or diagnosis. For severe symptoms, pregnancy danger signs, children with serious illness, chest pain, breathing difficulty, stroke-like weakness, or major injury, seek urgent care.

Which doctor may help?

Start with a registered doctor or the nearest qualified health center.

What to tell the doctor

  • Write when the problem started and how it changed.
  • Bring old prescriptions, investigation reports, and current medicines.
  • Write allergies, pregnancy status, diabetes, kidney/liver disease, and major past illnesses.
  • Bring one family member if the patient is weak, elderly, confused, or a child.

Questions to ask

  • What is the most likely cause of my symptoms?
  • Which danger signs mean I should go to hospital quickly?
  • Which tests are necessary now, and which can wait?
  • How should I take medicines safely and what side effects should I watch for?
  • When should I come for follow-up?

Tests to discuss

  • Vital signs: temperature, pulse, blood pressure, oxygen saturation
  • Basic physical examination by a clinician
  • CBC, urine test, blood sugar, or imaging only when clinically needed

Avoid these mistakes

  • Do not use antibiotics, steroid tablets/injections, or strong painkillers without proper medical advice.
  • Do not hide pregnancy, kidney disease, ulcer, allergy, or blood thinner use.
  • Do not delay emergency care when danger signs are present.

Medicine safety and first-aid guide

This section is for patient education only. It does not replace a doctor, pharmacist, or emergency care.

Safe first steps

  • Rest, drink safe water, and observe symptoms carefully.
  • Keep a written note of symptoms, duration, temperature, medicines already taken, and allergy history.
  • Seek medical care quickly if symptoms are severe, worsening, or unusual for the patient.

OTC medicine safety

  • For mild pain or fever, ask a registered pharmacist or doctor before using common over-the-counter pain/fever medicines.
  • Do not combine multiple pain medicines without advice, especially if you have kidney disease, liver disease, stomach ulcer, asthma, pregnancy, or take blood thinners.
  • Do not give adult medicines to children unless a qualified clinician advises it.

Avoid these mistakes

  • Do not start antibiotics without a proper medical decision.
  • Do not use steroid tablets or injections casually for quick relief.
  • Do not delay emergency care because of home remedies.

Get urgent help if

  • Severe symptoms, confusion, fainting, breathing difficulty, chest pain, severe dehydration, or sudden weakness need urgent medical care.
Medicine names, dose, and timing must be decided by a qualified clinician or pharmacist after checking age, pregnancy, allergy, other diseases, and current medicines.

For rural patients and family caregivers

Patient health record and symptom diary

Write your symptoms, medicines already taken, test results, and questions before visiting a doctor. This note stays on your device unless you print or copy it.

Doctor to discuss: Doctor / qualified healthcare provider
Tests to discuss with doctor
  • Basic vital signs: temperature, pulse, blood pressure, oxygen level if needed
  • Relevant blood, urine, imaging, or specialist tests only after clinical assessment
Questions to ask
  • What is the most likely cause of my symptoms?
  • Which warning signs mean I should go to emergency care?
  • Which tests are really needed now?
  • Which medicines are safe for my age, pregnancy status, allergy, kidney/liver/stomach condition, and current medicines?

Emergency warning signs such as chest pain, severe breathing difficulty, sudden weakness, confusion, severe dehydration, major injury, or loss of bladder/bowel control need urgent medical care. Do not wait for online information.

Safe pathway to proper treatment

Care roadmap for: Types of Diabetes Mellitus – A to Z

Use this simple roadmap to understand the next safe steps. It is educational and does not replace examination by a doctor.

Go to emergency care if you notice:
  • Severe or rapidly worsening symptoms
  • Breathing difficulty, chest pain, fainting, confusion, severe weakness, major injury, or severe dehydration
Doctor / service to discuss: Qualified healthcare provider; specialist depends on symptoms and examination.
  1. Step 1

    Check danger signs first

    If danger signs are present, seek emergency care and do not wait for online information.

  2. Step 2

    Record the symptom story

    Write when symptoms started, severity, medicines already taken, allergies, pregnancy status, and test results.

  3. Step 3

    Visit a qualified clinician

    A doctor, nurse, or qualified healthcare provider can examine you and decide which tests or treatment are needed.

  4. Step 4

    Do only useful tests

    Do tests after clinical assessment. Avoid unnecessary tests, random antibiotics, or repeated medicines without diagnosis.

  5. Step 5

    Follow up and return early if worse

    If symptoms worsen, new warning signs appear, or treatment is not helping, return for review quickly.

Rural patient practical tips
  • Take a written symptom diary and all previous prescriptions/test reports.
  • Do not hide medicines already taken, even herbal or over-the-counter medicines.
  • Ask which warning signs mean urgent referral to hospital.

This roadmap is for education. A real diagnosis and treatment plan requires history, examination, and clinical judgment.

RX Patient Help

Ask a health question safely

Write your symptom story. A health professional or site editor can review it before any answer is prepared. This box is not for emergency care.

Emergency first: Severe chest pain, breathing trouble, unconsciousness, stroke signs, severe injury, heavy bleeding, or rapidly worsening symptoms need urgent local medical care now.

Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

References

Add references, clinical guidelines, textbooks, journal articles, or trusted medical sources here. You can edit this area from the RX Article Professional Blocks panel.

More from this topic
  1. Isolated Congenital Elbow Dislocation

    DefinitionIsolated congenital? elbow dislocation is a very rare condition present from birth. In most medical papers, the more exact name is congenital? radial head dislocation, because...

    April 2, 2026 • Gastrointestinal, Pelvic & Liver Disease, (A - Z)
  2. Alacrimia-Choreoathetosis-Liver Dysfunction Syndrome

    DefinitionAlacrimia-choreoathetosis-liver dysfunction syndrome is a very rare inherited disease. It is now usually called NGLY1 deficiency or NGLY1-related congenital? disorder of deglycosylation. In this condition, the...

    April 1, 2026 • Gastrointestinal, Pelvic & Liver Disease, (A - Z)
  3. Congenital Diarrhea Caused by Mutation in DGAT1

    DefinitionCongenital? diarrhea? caused by mutation in DGAT1 is a very rare inherited disease. It usually starts in the newborn period or in early infancy. The baby...

    April 1, 2026 • Gastrointestinal, Pelvic & Liver Disease, (A - Z)
  4. Congenital Chronic Diarrhea with Protein-Losing Enteropathy

    DefinitionCongenital? chronic? diarrhea? with protein-losing enteropathy is not usually one single disease name. It is a clinical description for a baby or young child who has...

    April 1, 2026 • Gastrointestinal, Pelvic & Liver Disease, (A - Z)
  5. Congenital Chronic Diarrhea with Exudative Enteropathy

    DefinitionCongenital? chronic? diarrhea? with exudative enteropathy is a rare inherited early-life intestinal disease in which the gut does not handle nutrients, fluids, and proteins normally, so...

    April 1, 2026 • Gastrointestinal, Pelvic & Liver Disease, (A - Z)
  6. Congenital Diarrhea 7 with Exudative Enteropathy

    DefinitionCongenital? diarrhea? 7 with exudative enteropathy is a very rare inherited intestinal disease. It usually starts in the newborn period or early infancy. The baby has...

    March 31, 2026 • Gastrointestinal, Pelvic & Liver Disease, (A - Z)
  7. Chronic Infantile Diarrhea Due to Guanylate Cyclase 2C Overactivity

    DefinitionChronic? infantile diarrhea? due to guanylate cyclase 2C overactivity is a very rare inherited bowel disease. It usually starts very early in life, often in infancy,...

    March 31, 2026 • Gastrointestinal, Pelvic & Liver Disease, (A - Z)
  8. Tufting Enteropathy

    DefinitionTufting enteropathy is a very rare inherited bowel disease. It usually starts in the first days, weeks, or months of life. The baby has severe watery...

    March 31, 2026 • Gastrointestinal, Pelvic & Liver Disease, (A - Z)
  9. Secretory Diarrhea Caused by Mutation in EPCAM

    DefinitionSecretory diarrhea? caused by mutation in EPCAM is usually called congenital? tufting enteropathy or intestinal epithelial dysplasia. It is a very rare inherited disease that starts...

    March 31, 2026 • Gastrointestinal, Pelvic & Liver Disease, (A - Z)
  10. Intestinal Epithelial Dysplasia

    DefinitionIntestinal epithelial dysplasia, also called tufting enteropathy or congenital? tufting enteropathy, is a very rare inherited disease of the gut lining. In this condition, the cells...

    March 31, 2026 • Gastrointestinal, Pelvic & Liver Disease, (A - Z)