Whilst fatty liver disease predominantly affects adults, infants can be born with genetic or metabolic conditions that cause abnormal fat accumulation in the liver. True non-alcoholic fatty liver disease (NAFLD) is exceptionally rare at birth. Instead, newborns may present with inherited disorders affecting how the liver processes fats, such as fatty acid oxidation defects or lysosomal storage diseases. These congenital conditions differ fundamentally from acquired fatty liver seen in older children and adults. Early recognition is crucial, as many require prompt specialist intervention to prevent serious complications including liver failure or metabolic crises.

Can You Be Born With Fatty Liver?

Whilst fatty liver disease is predominantly associated with adults, particularly those with obesity or metabolic syndrome, it is possible for infants and children to be born with or develop liver conditions that involve fat accumulation. However, true non-alcoholic fatty liver disease (NAFLD) as seen in adults is exceptionally rare at birth. Instead, newborns may present with congenital metabolic disorders or genetic conditions that affect how the liver processes and stores fats.

The liver plays a crucial role in metabolising nutrients, producing proteins, and detoxifying harmful substances. When genetic mutations or inherited metabolic errors are present from birth, the liver's normal function can be compromised, leading to abnormal fat deposition within liver cells (hepatocytes). These conditions differ fundamentally from the acquired fatty liver disease commonly seen in older children and adults, which typically develops due to dietary factors, obesity, or insulin resistance.

Neonatal liver disease encompasses a range of conditions, some of which may involve hepatic steatosis (fat accumulation in the liver). These can include inherited disorders of fatty acid oxidation, lysosomal storage diseases, and certain mitochondrial disorders. It is important to distinguish these from other serious neonatal liver conditions such as biliary atresia, which presents with cholestasis (reduced bile flow) rather than fatty liver but requires equally urgent assessment. Early identification is essential, as many of these conditions require prompt intervention to prevent serious complications such as liver failure, developmental delays, or metabolic crises.

Parents should be aware that whilst congenital liver conditions are relatively uncommon, newborn screening programmes in the UK help identify some metabolic disorders early. Urgent medical assessment is warranted if a baby shows concerning signs, including:

• Prolonged jaundice (persisting beyond 14 days in term infants or 21 days in premature babies)

• Pale or chalky-coloured stools

• Dark urine

• Poor feeding or failure to thrive

• An enlarged liver or abdomen

• Easy bruising or bleeding

Any jaundiced infant with pale stools or dark urine requires same-day assessment and measurement of conjugated (direct) bilirubin levels, as this may indicate cholestasis. Early diagnosis through specialist paediatric hepatology services can significantly improve outcomes and guide appropriate management strategies, particularly for conditions such as biliary atresia where early surgical intervention (Kasai portoenterostomy, ideally before 60 days of age) improves long-term outcomes.

Causes of Fatty Liver in Infants and Children

Fatty liver in the paediatric population arises from distinctly different causes compared to adults. In infants, the most common aetiologies are inherited metabolic disorders that disrupt normal fat metabolism. These include disorders of fatty acid oxidation, such as medium-chain acyl-CoA dehydrogenase deficiency (MCADD), which prevents the body from properly breaking down certain fats for energy. When fatty acids cannot be metabolised efficiently, they accumulate in the liver and other organs, potentially causing hepatic steatosis.

Glycogen storage diseases represent another important group of conditions that can cause liver enlargement and fat accumulation from birth or early infancy. In these disorders, genetic mutations affect enzymes responsible for glycogen metabolism, leading to abnormal storage of glycogen and sometimes fat within hepatocytes. Type I glycogen storage disease (von Gierke disease), for instance, commonly presents with hepatomegaly and can be associated with fatty infiltration of the liver.

Other critical metabolic causes that can present in early infancy include galactosaemia and tyrosinaemia type 1, both of which can cause acute liver dysfunction and require urgent dietary modification or specific treatment to prevent serious complications. These conditions may be identified through newborn screening or clinical presentation with jaundice, hypoglycaemia, or liver failure.

In older infants and children, acquired fatty liver disease may develop, though this typically occurs after infancy. Paediatric NAFLD has become increasingly recognised in recent years, paralleling rising childhood obesity rates. Risk factors include excessive caloric intake, sedentary lifestyle, insulin resistance, and genetic predisposition. Children with obesity, type 2 diabetes, or metabolic syndrome are at higher risk.

Intestinal failure-associated liver disease (IFALD), also known as total parenteral nutrition (TPN)-associated liver disease, can occur when infants cannot feed normally and require prolonged intravenous nutrition. This can cause liver complications including steatosis, particularly with extended use. Additionally, certain medications and rare conditions such as Reye's syndrome (now very uncommon and classically linked to aspirin use in children, which is generally avoided in those under 16 unless specifically prescribed) have been associated with hepatic fat accumulation. Vertical transmission of hepatitis C from mother to child is uncommon in current UK practice due to screening and treatment pathways; when it does occur, the risk of steatosis varies by viral genotype. Each cause requires specific diagnostic approaches and tailored management strategies to prevent progression to more serious liver disease.

Genetic Conditions That Affect the Liver From Birth

Several genetic conditions can affect liver function from birth, some of which involve abnormal fat metabolism or accumulation. Fatty acid oxidation disorders comprise a group of inherited conditions where the body cannot properly break down fatty acids to produce energy. MCADD is the most common of these disorders in the UK and is included in the newborn bloodspot screening programme. Affected infants may appear healthy initially but can develop serious complications during periods of fasting or illness when the body relies more heavily on fat metabolism.

Lysosomal storage diseases, such as Niemann-Pick disease and Gaucher disease, result from deficiencies in specific enzymes needed to break down lipids and other substances. These conditions lead to accumulation of fatty materials in the liver, spleen, and other organs. Niemann-Pick disease encompasses several subtypes: acid sphingomyelinase deficiency (ASMD, formerly Niemann-Pick types A and B) now has enzyme replacement therapy (olipudase alfa) available for non-central nervous system manifestations, whilst Niemann-Pick disease type C uses substrate reduction therapy (such as miglustat) rather than enzyme replacement. Gaucher disease can present with hepatosplenomegaly (enlarged liver and spleen) from infancy and has specific enzyme replacement therapies available.

Mitochondrial disorders affect the cellular powerhouses responsible for energy production and can manifest with liver involvement. These conditions may present with hepatic steatosis, liver failure, or elevated liver enzymes. Alpers-Huttenlocher syndrome, a severe mitochondrial disorder, typically presents in infancy or early childhood with liver disease and neurological deterioration.

Alpha-1 antitrypsin deficiency is an important genetic cause of paediatric liver disease, most commonly presenting with neonatal cholestasis and jaundice. Whilst it is primarily a disorder affecting protein folding and accumulation rather than fat metabolism, some affected infants develop liver inflammation, fibrosis, or cirrhosis, and steatosis may coexist. The condition can progress to chronic liver disease in a proportion of cases.

Wilson's disease, though usually presenting later in childhood or adolescence, is a genetic disorder affecting copper metabolism that can cause liver damage. Diagnosis relies on age-appropriate testing strategies, as ceruloplasmin and copper studies are more helpful in older children; genetic testing is undertaken under specialist guidance. Genetic testing and specialist paediatric hepatology assessment are essential for accurate diagnosis and appropriate management of these complex conditions.

Diagnosing Liver Problems in Newborns and Young Children

Diagnosing liver conditions in newborns and young children requires a systematic approach combining clinical assessment, laboratory investigations, and imaging studies. Initial evaluation typically begins when concerning signs are identified, such as prolonged neonatal jaundice (persisting beyond 14 days in term infants or 21 days in premature babies), pale or acholic (chalky-coloured) stools, dark urine, poor weight gain, or an enlarged liver detected on examination.

Laboratory investigations form the cornerstone of diagnosis. Blood tests assess liver function through measurement of bilirubin levels (both conjugated and unconjugated), liver enzymes (ALT, AST, GGT, alkaline phosphatase), albumin, and prothrombin time/international normalised ratio (PT/INR) to gauge synthetic function. Conjugated bilirubin greater than 25 micromol/L (or more than 20% of total bilirubin) indicates cholestasis and requires urgent specialist assessment. Elevated transaminases may indicate hepatocellular injury, whilst raised GGT and alkaline phosphatase suggest cholestatic disease.

Additional tests may include blood glucose monitoring, ammonia levels, lactate, alpha-1 antitrypsin level and phenotype, plasma acylcarnitine profile, and urine organic acids to screen for inherited metabolic disorders. In unwell neonates, testing for congenital infections such as herpes simplex virus (HSV) and cytomegalovirus (CMV) may be appropriate.

The newborn bloodspot screening programme in the UK tests for several conditions that can affect the liver, including MCADD and certain other metabolic disorders. When initial screening suggests a problem, confirmatory testing through specialised metabolic laboratories is arranged. Genetic testing has become increasingly important, with whole exome or genome sequencing sometimes employed to identify rare inherited conditions.

Imaging studies provide valuable structural information. Ultrasound scanning is the first-line imaging modality, being non-invasive and readily available. It can identify liver size, texture abnormalities, bile duct dilatation, and assess blood flow. More advanced imaging such as MRI may be used to characterise liver lesions or assess for fat content. Hepatobiliary scintigraphy (HIDA scan) may be used selectively under specialist guidance. In selected cases, liver biopsy remains the gold standard for definitive diagnosis, allowing histological examination and sometimes enzymatic or genetic analysis of liver tissue.

NICE guidance (NG98) emphasises the importance of urgent specialist referral for infants with suspected liver disease. Suspected biliary atresia warrants same-day discussion or referral to a paediatric hepatology or surgical centre, as earlier Kasai portoenterostomy (ideally before 60 days of age) significantly improves outcomes. Paediatric hepatology centres provide multidisciplinary assessment and can coordinate complex investigations. Early diagnosis is crucial, as some conditions require immediate dietary modifications or specific treatments to prevent irreversible liver damage or metabolic decompensation.

Treatment and Management Options for Paediatric Liver Conditions

Management of paediatric liver conditions varies considerably depending on the underlying diagnosis, but generally involves a multidisciplinary approach coordinated through specialist paediatric hepatology services. For inherited metabolic disorders, treatment often centres on dietary modification and metabolic management. Children with fatty acid oxidation disorders, for instance, require regular feeding schedules to avoid prolonged fasting, with some needing cornstarch supplements or special formulas to maintain blood glucose levels. During illness, emergency regimens involving glucose-containing fluids may be necessary to prevent metabolic crises.

For conditions such as galactosaemia, immediate exclusion of galactose (lactose) from the diet is essential and life-saving. Tyrosinaemia type 1 requires a low-tyrosine, low-phenylalanine diet alongside nitisinone therapy under specialist supervision.

Nutritional support is fundamental across many paediatric liver conditions. A specialist paediatric dietitian works closely with families to ensure adequate caloric intake whilst managing specific dietary restrictions. Fat-soluble vitamin supplementation (vitamins A, D, E, and K) is often required in cholestatic liver disease where bile flow is impaired. For infants on total parenteral nutrition, careful monitoring and adjustment of lipid content helps minimise intestinal failure-associated liver disease (IFALD).

For conditions like glycogen storage diseases, treatment involves maintaining stable blood glucose through frequent feeds, uncooked cornstarch, or continuous overnight gastric feeding. Strict dietary adherence prevents hypoglycaemia and reduces hepatic complications. Some lysosomal storage diseases now have specific enzyme replacement therapies available: for example, imiglucerase or velaglucerase alfa for Gaucher disease, and olipudase alfa for acid sphingomyelinase deficiency (ASMD). Niemann-Pick disease type C is managed with substrate reduction therapy such as miglustat. Effectiveness varies by condition and liver involvement may not always respond fully.

Pharmacological interventions may include ursodeoxycholic acid for selected cholestatic conditions to improve bile flow, though its use is often off-label in paediatrics and benefits vary by underlying aetiology; it should be prescribed under specialist advice. For Wilson's disease, treatment involves copper chelation with penicillamine or trientine under specialist supervision, alongside dietary copper restriction and monitoring. Regular monitoring through blood tests, growth assessment, and developmental surveillance is essential.

Liver transplantation represents a life-saving option for children with progressive liver failure or certain metabolic disorders where the liver is the primary site of the enzymatic defect. Paediatric transplant centres in the UK achieve excellent outcomes, with careful selection and lifelong immunosuppression required.

Parents should maintain close contact with their child's healthcare team and seek urgent medical attention if their child becomes unwell, refuses feeds, or shows signs of deterioration. Patient safety is paramount, and families receive individualised emergency management plans for conditions requiring specific interventions during illness. Support groups and charities such as the Children's Liver Disease Foundation provide valuable resources and peer support for families navigating these challenging conditions.

Frequently Asked Questions