Classical genetics: carriers
Diseases that depend on a single gene, with classical inheritance. The math here is exact —as in Predispositions, and unlike the polygenic scores, which estimate—. ACMG recommends offering this screening to every person who is trying to conceive or is already pregnant.
All 18 conditions, by what they mean for your children
Being a carrier does not mean having the disease
You are not a carrier.
Health: no change.
You are a healthy carrier. This is the case for you in the genes flagged below.
Health: no change for autosomal recessive conditions. For X-linked ones a single copy can have consequences, and that row says so.
The disease is present.
This is the only situation in which the disease appears.
So what good is knowing it?
For one thing only: reproductive decisions. In an autosomal recessive condition, being a carrier changes nothing about your health. It matters only if your partner turns out to be a carrier of the same gene: only then does each pregnancy have a 25% probability that the baby receives both affected copies. X-linked conditions are the exception, they are flagged as such, and there a consultation is warranted.
That is why this result, on its own, is incomplete: the test that changes clinical management is your partner's. Roughly 1 in 4 people is a carrier of something — that is normal, not a rare finding and not bad news.
Cystic fibrosis
You are a healthy carrier: you have one copy with the variant and one normal copy, and that does not affect your health. It only matters if your partner is also a carrier of the same gene — in that case, each pregnancy would have a 25% probability of cystic fibrosis. The appropriate step is to test your partner. You will also see CFTR in Pharmacogenomics: there the question is a different one (whether CFTR modulators apply to you) and the answer is no, precisely because you are a carrier and not a patient.
See the 13 conditions analyzed with no findings
These are the conditions in which the test measured at least one variant and none appeared. How much of the known total it measures in each is in its own column: the lower it is, the less a negative reassures.
| Condition | Gene | Inheritance | Variants | Chip coverage | Result |
|---|---|---|---|---|---|
Nonsyndromic hearing loss You do not carry the most common variant of hereditary congenital hearing loss. | GJB2 (conexina 26) 35delG | Autosomal recessive | 1 in 33 | The chip covers this disease well | Not a carrier |
Gaucher disease Without the evaluated variant. | GBA N370S | Autosomal recessive | 1 in 100 (higher in the Ashkenazi population) | Partial coverage: only the most frequent variants | Not a carrier |
Phenylketonuria No common variants detected. It is the disease that mandatory newborn screening looks for. | PAH Panel of common variants | Autosomal recessive | 1 in 50 | Partial coverage: only the most frequent variants | Not a carrier |
Beta-thalassemia Relevant because of Italian and Spanish ancestry, very common in Argentina. No variants were detected. | HBB Mediterranean panel | Autosomal recessive | 1 in 30 in the Mediterranean population | Partial coverage: only the most frequent variants | Not a carrier |
Alpha-1 antitrypsin deficiency Without the risk alleles for emphysema and liver disease due to alpha-1 deficiency. | SERPINA1 PI*Z / PI*S | Autosomal recessive | 1 in 25 for PI*Z | The chip covers this disease well | Not a carrier |
Congenital adrenal hyperplasia No common variants. The gene has a neighboring pseudogene that complicates reading it on an array: a negative result here does not completely rule it out. | CYP21A2 Variantes frecuentes | Autosomal recessive | 1 in 60 | Partial coverage: only the most frequent variants | Not a carrier |
G6PD deficiency Important because it affects which drugs can be prescribed (some antimalarials, nitrofurantoin, high doses of vitamin C). No variants detected. | G6PD Mediterránea / A− | X-linked | Variable depending on origin | Partial coverage: only the most frequent variants | Not a carrier |
Sickle cell anemia The entire disease is due to ONE single variant, so the chip sees it perfectly and the negative result is conclusive. Relevant because of the African component of the Argentine population. | HBB HbS (rs334) | Autosomal recessive | 1 in 12 among people of African descent | The chip covers this disease well | Not a carrier |
MCAD deficiency A single change explains the majority of cases in the European population. It is a disorder of fat metabolism that can be severe and that newborn screening looks for. | ACADM K304E | Autosomal recessive | 1 in 65 in the European population | The chip covers this disease well | Not a carrier |
Tay-Sachs disease The chip carries the Ashkenazi founder variants and some common ones. Outside those populations the disease may be due to rare variants that the array does not see. | HEXA Variantes fundadoras | Autosomal recessive | 1 in 27 in the Ashkenazi population | Partial coverage: only the most frequent variants | Not a carrier |
Classic galactosemia Two variants explain a good portion of the cases in the European population, and the chip covers them. It is also included in newborn screening. | GALT Q188R, K285N | Autosomal recessive | 1 in 70 | Partial coverage: only the most frequent variants | Not a carrier |
Wilson disease Copper accumulation, treatable if detected in time. More than 800 variants have been described: the chip sees only the common ones, so a negative does not rule it out. | ATP7B H1069Q + | Autosomal recessive | 1 in 90 | Partial coverage: only the most frequent variants | Not a carrier |
Mucopolysaccharidosis type I (Hurler) The chip carries the two most common variants in the European population, which explain about half of the cases. The other half is due to rare or private variants that an array CANNOT see: if there is clinical suspicion or a history, it is appropriate to sequence the gene and measure the enzyme. | IDUA W402X, Q70X | Autosomal recessive | 1 in 100 approx. | Partial coverage: only the most frequent variants | Not a carrier |
This screening covers the most common founder variants of each gene, which is what an array can read. It does NOT replace a carrier panel by sequencing: a negative result greatly reduces the probability of being a carrier, but does not bring it to zero. If you are trying to conceive or already pregnant, discuss it with the team — and what changes management most is testing the partner, not one person alone.